Electrochemistry & pH measurement
The Electrochemistry & pH Measurement range brings together electrodes and accessories for precise pH, redox and conductivity measurements. LT Laborhandel stocks WTW pH electrodes with glass or plastic shafts, redox and Ag electrodes, as well as DIN/NIST buffer solutions for calibration. You can find suitable measuring instruments in the Scales & Measurement category. Our service team will be happy to advise you on the right electrode.
WTW SenTix 41 analogue pH electrode, integrated temperature sensor, 103635
The WTW SenTix 41 analogue pH electrode is a tried-and-tested electrochemical system solution for reliable, low-maintenance pH measurement in routine laboratory applications, educational institutions and field measurements. Designed for use with classic analogue pH meters from the WTW inoLab and Profiline series, this high-quality electrode offers precise signal transmission and extremely simple handling. For daily monitoring measurements in aqueous media, wastewater samples or environmental investigations, the focus is on straightforward, rapid deployment – which this robust combination probe guarantees whilst being gentle on materials and ensuring process reliability. Traditional analogue technology and integrated temperature compensation The mechatronic system architecture of the SenTix 41 is based on reliable, analogue signal transmission. The measured potential is transmitted via a shielded fixed cable directly to the analogue input stage of the pH meter. A key functional feature is the NTC 30 kOhm temperature sensor integrated into the sensor head. This sensor measures the sample temperature simultaneously with the pH value, enabling the connected meter to perform automatic temperature compensation in real time. This reliably eliminates thermodynamically induced measurement errors caused by fluctuating ambient temperatures, without the need to immerse a separate temperature sensor in the sample. Low-maintenance gel electrolyte and mechanical breakage protection The material design is consistently optimised for durability and minimal maintenance in everyday laboratory use. The electrode is fitted with a chemically resistant and extremely break-resistant POM plastic shaft. This shaft encloses the sensitive glass membrane like a mechanical protective cage and prevents damage in the event of falls or contact with vessel walls. A maintenance-free gel electrolyte, combined with a tried-and-tested fibre diaphragm, serves as the reference system. This sealed system permanently eliminates the need for the tedious refilling of liquid KCl solution and significantly reduces the risk of diaphragm blockages in multi-user operations. Universal connectivity and ergonomic laboratory use To ensure seamless integration into equipment, the SenTix 41 features a permanently attached 1-metre cable terminated in tried-and-tested standard connectors. The pH channel is connected via a standard DIN plug, whilst the integrated temperature sensor is connected via a 4 mm banana plug. This standardised plug combination guarantees universal compatibility with a wide range of analogue measuring stations on the market. The flexible cable ensures optimal ergonomic movement and allows fatigue-free working when carrying out sequential measurements on larger sample series directly at the workstation. Technical details Measurement & Sensor Technology Sensor type: Analogue pH combination electrode Model: SenTix 41 pH measurement range: 0 to 14 pH Temperature element: Integrated NTC 30 kOhm temperature sensor Operating temperature range: 0 to 80 °C Design & dimensions Shaft material: Highly robust plastic shaft (POM) with integrated protective cage Electrolyte: Low-maintenance gel electrolyte (non-refillable) Diaphragm: Reliable fibre diaphragm Shaft length: 120 mm Shaft diameter: 12 mm Connection type: Fixed cable, length 1.0 m Connector type: DIN plug (for pH) and 4 mm banana plug (for temperature) Operating conditions Maintenance: Low maintenance (no refilling of liquids required) Main applications: Routine laboratory measurements, schools and training, field measurements, general aqueous media Contents 1 x WTW SenTix 41 analogue pH electrode with 1 m fixed cable (MPN: 103635) 1 x storage cap with original storage solution 1 x Quick start guide / Quality certificate Important note: pH buffer solutions for regular calibration and the analogue pH meter itself are not included as standard and must be ordered separately. Individual requirements & accessories To ensure consistently high measurement accuracy of the WTW SenTix 41, regular recalibration of the measuring station is essential. For this purpose, our range includes certified WTW technical buffer solutions in practical dosing bottles (pH 4.01, pH 7.00 and pH 10.01). For the proper care and storage of the pH-sensitive glass membrane during measurement breaks, we strongly recommend the use of the original 3 mol/l KCl storage solution. Should the electrode ever become contaminated with stubborn sample residues during the rigours of everyday laboratory work, we offer special cleaning concentrates for gentle regeneration. Please make use of our procurement service when putting together your laboratory equipment.
WTW SenTix 81 analogue precision pH electrode, glass shaft, 103642
The WTW SenTix 81 analogue precision pH electrode represents a premium-class metrological system solution for high-precision and reliable pH measurement in demanding laboratory applications. Designed for use with classic analogue pH meters from the WTW inoLab and Profiline series, this high-quality glass electrode offers excellent signal transmission and the highest measurement accuracy. For complex tasks in chemical research, pharmaceutical quality control or university-level analysis, rapid and stable potential stabilisation is the primary criterion for ensuring reproducible measurement results in a process-reliable manner that minimises damage to the sample. Traditional analogue technology and integrated temperature compensation The mechatronic system architecture of the SenTix 81 is based on reliable, analogue signal transmission. The measured potential is transmitted via a high-quality, shielded fixed cable directly to the analogue input stage of the pH meter. A key functional feature is the 30 kOhm NTC temperature sensor integrated into the sensor head. This sensor measures the sample temperature simultaneously with the pH value, enabling the connected meter to perform automatic temperature compensation in real time. This reliably eliminates thermodynamically induced measurement errors caused by fluctuating ambient temperatures, without the need to immerse a separate temperature sensor in the sample. High-quality platinum diaphragm and refillable reference system The materials-science-based design is uncompromisingly optimised for maximum precision and fast response times. The electrode features a chemically highly resistant glass shaft and a cylindrical glass diaphragm. A tried-and-tested liquid electrolyte (3 mol/l KCl) serves as the reference system; this can be easily topped up or completely replaced via a sealable opening at the top of the glass shaft. A standout technological feature is the integrated platinum diaphragm. This specialised diaphragm ensures a continuous and uniform flow of electrolyte without the risk of blockages, even with challenging sample media such as emulsions, suspensions or slightly viscous solutions. Universal connectivity and ergonomic laboratory use To ensure seamless integration into laboratory set-ups, the SenTix 81 features a permanently attached, 1-metre-long cable terminated in tried-and-tested standard connectors. The pH channel is connected via a standard DIN plug, whilst the integrated temperature sensor is connected via a 4 mm banana plug. This standardised plug combination guarantees universal compatibility with a wide range of analogue measuring stations on the market. The flexible cable ensures optimal ergonomic movement and allows fatigue-free working when sequentially measuring larger sample series directly at the workstation. Technical Details Measurement & Sensor Technology Sensor type: Analogue pH combination electrode Model: SenTix 81 pH measurement range: 0 to 14 pH Temperature element: Integrated NTC 30 kOhm temperature sensor Operating temperature range: 0 to 100 °C Construction & dimensions Shaft material: Highly chemically resistant glass shaft Electrolyte: Liquid electrolyte (3 mol/l KCl, refillable) Diaphragm: High-quality platinum diaphragm Shaft length: 120 mm Shaft diameter: 12 mm Connection type: Fixed cable, length 1.0 m Connector combination: Waterproof DIN plug (for pH) and 4 mm banana plug (for temperature) Operating conditions Maintenance: Refillable (KCl solution replaceable) Main applications: Demanding laboratory measurements, chemical analysis, challenging sample media, general aqueous media Contents 1 x WTW SenTix 81 analogue pH glass electrode with 1 m fixed cable (MPN: 103642) 1 x storage cap with original storage solution 1 x pipette bottle with refill electrolyte (3 mol/l KCl) 1 x Quick start guide / Quality certificate Important note: pH buffer solutions for regular calibration and the analogue pH meter itself are not included as standard and must be ordered separately. Individual requirements & accessories To ensure consistently high measurement accuracy of the WTW SenTix 81, regular recalibration of the measuring station is essential. For this purpose, our range includes certified WTW technical buffer solutions in practical dosing bottles (pH 4.01, pH 7.00 and pH 10.01). For the proper care and storage of the pH-sensitive glass membrane during measurement breaks, we strongly recommend the use of the original 3 mol/l KCl storage solution. Should the electrode ever become contaminated with stubborn sample residues during the rigours of everyday laboratory work, we offer special cleaning concentrates for gentle regeneration. Please make use of our technical procurement service when putting together your laboratory equipment.
WTW SenTix 61 glass pH electrode, refillable, DIN connector, 103640
Precision thanks to liquid electrolyte The WTW SenTix ® 61 is a high-quality standard pH electrode with a glass shaft, designed for demanding measurement tasks in the laboratory. Unlike gel-filled electrodes, this model utilises a liquid reference electrolyte (3 mol/l KCl, free from silver ions). This ensures a faster electrolyte flow and more stable potential formation, particularly with difficult samples. As the electrolyte is refillable, the user benefits from a significantly longer service life for the electrode compared with maintenance-free models. High-quality platinum diaphragm The built-in platinum wire diaphragm ensures a reliable connection between the sample and the reference system. It is characterised by a constant flow rate and is less prone to blockages than conventional ceramic diaphragms. The robust glass shaft is highly chemically resistant, easy to clean and ideally suited for use across a wide temperature range from 0 to 100 °C. Compatibility and connection The SenTix ® 61 (variant 103640) is fitted with a permanently attached 1-metre cable and a waterproof DIN plug. This connection standard ensures reliable signal transmission and is perfectly compatible with numerous WTW pH metres (e.g. the inoLab ® series) as well as other measuring instruments with a DIN socket. Please note that this model does not have an integrated temperature sensor; temperature measurement must be carried out separately if required. Technical details pH measurement range: 0 – 14 Temperature range: 0 – 100 °C Reference electrolyte: KCl 3 mol/l (liquid, refillable) Diaphragm: platinum Shaft material: Glass Shaft length / diameter: 120 mm / 12 mm Temperature sensor: No (NTC not integrated) Connection: DIN plug (waterproof) Cable length: 1 m (fixed) Diaphragm shape: Cylinder Diaphragm resistance (at 25°C): < 600 MOhm Contents of delivery WTW SenTix ® 61 pH electrode Fixed cable (1 m) with DIN plug Operating instructions Note: An initial supply of electrolyte is included; refill bottles must be ordered separately. Customised requirements & procurement service Do you need the correct electrolyte solution (KCl 3 mol/l), storage solution or a model with an integrated temperature sensor (e.g. SenTix 81)? We can advise you on optimal electrode maintenance. Please contact our procurement service for accessories and spare parts.
WTW SenTix 940 digital IDS pH electrode, plastic shaft, 1.5 m fixed cable, 103740
The WTW SenTix 940 digital IDS pH electrode represents a highly advanced, electrochemical system solution for precise and low-maintenance pH measurement in both laboratory and field applications. Designed for use with WTW IDS multi-parameter analysers, this digital electrode enables error-free signal transmission and comprehensive documentation. When carrying out demanding measurement series in aqueous samples, environmental analyses or industrial quality control, the elimination of signal interference caused by long cable runs is the primary criterion for guaranteeing highly precise measurements whilst minimising damage to the sample. Intelligent IDS sensor technology and digital signal processing The mechatronic system architecture of the SenTix 940 is based on innovative IDS (Intelligent Digital Sensors) technology. Unlike conventional analogue probes, the sensitive analogue voltage signal is digitised and calibrated directly within the internal sensor assembly. This transient signal processing completely eliminates electromagnetic interference. An integrated data memory permanently stores the sensor’s specific serial number as well as a calibration history for up to 10 calibrations. Thanks to the intelligent QSC (Quality Sensor Control) function, the sensor continuously assesses its current status and displays this directly on the measuring instrument, guaranteeing maximum process reliability with every measurement. Low-maintenance gel electrolyte and robust materials engineering The material design is consistently optimised for mechanical resilience and minimal maintenance intervals. The electrode features a shatterproof plastic shaft made of POM, which provides optimum protection for the sensitive glass diaphragm against mechanical impact during field measurements. A tried-and-tested gel electrolyte, combined with a fibre diaphragm, serves as the reference system. This low-maintenance system eliminates the need to top up liquid KCl electrolyte and drastically reduces the risk of diaphragm blockages, which significantly extends the sensor’s service life in multi-user operation. Integrated temperature compensation and process-reliable fixed cable To ensure precise measurement results, the SenTix 940 features a built-in 30 kOhm NTC temperature sensor, which provides automatic, real-time temperature compensation of the pH value. The connection to the IDS meter is via a permanently fitted, 1.5-metre-long cable with a waterproof, digital IDS connector. This fixed cable connection offers optimum mechanical protection against the ingress of splash water and moisture and guarantees uninterrupted signal transmission as well as convenient handling at the laboratory workstation or directly in mobile field applications. Technical details Measurement & Sensor Technology Sensor type: Digital IDS pH electrode Model: SenTix 940 pH measurement range: 0 to 14 pH Temperature element: Integrated NTC 30 kOhm temperature sensor Operating temperature range: 0 to 80 °C Calibration memory: Integrated memory for up to 10 calibrations Sensor evaluation: QSC-compatible (Quality Sensor Control) Design & dimensions Shaft material: Robust plastic shaft (POM) Electrolyte: Low-maintenance gel electrolyte Diaphragm: Fibre diaphragm Shaft length: 120 mm Shaft diameter: 12 mm Connection type: Fixed cable, length 1.5 m with digital IDS plug Serial number: Stored electronically within the sensor Operating conditions Maintenance: Low maintenance (no need to top up liquid electrolyte) Application: General-purpose aqueous media, laboratory and field measurements, quality control Contents 1 x WTW SenTix 940 digital IDS pH electrode with 1.5 m fixed cable (MPN: 103740) 1 x Watering cap with storage solution 1 x Quality certificate / Quick start guide Important note: pH buffer solutions, cleaning concentrates and the IDS meter itself are not included in the standard scope of delivery and must be ordered separately. Individual requirements & accessories To realise the full potential of the WTW SenTix 940, we recommend using it with a compatible WTW MultiLine or inoLab IDS meter. For regular recalibration and to ensure the integrity of the metrological chain, we offer certified WTW technical buffer solutions (pH 4.01, pH 7.00, pH 10.01) in our range. For the proper storage and care of the sensitive glass membrane, we recommend the original KCl storage solution. Please use our technical procurement service to put together your digital measuring station.
WTW SenTix 21 PH Electrode, Plastic Shaft, Gel Electrolyte, BNC Connector, 103631
Anyone who measures pH levels on a daily basis in waste water, aquarium water or at a training centre needs an electrode that combines ease of use with robust technology. The SenTix 21 pH electrode from WTW is designed precisely for this purpose: a plastic shaft, a maintenance-free gel electrolyte and a BNC connector that can also be used with measuring instruments from other manufacturers.Plastic shaft with maintenance-free gel electrolyteThe shaft is made of plastic (PPE/PS) and is therefore more resistant to impact than a glass electrode. The gel electrolyte is filled at the factory and does not need to be refilled; the fibre diaphragm establishes the electrical contact with the sample solution. The membrane resistance is less than 1 GOhm; the measuring range covers the entire pH scale from 0 to 14 at temperatures between 0 and 80 °C.BNC connector for flexible useThe SenTix 21 does not have an integrated temperature sensor and is connected via a 1 m long fixed cable with a BNC connector (coaxial connector to DIN 19262). Without the additional banana plug for a temperature signal, it can also be used with simpler measuring instruments and devices from other manufacturers featuring a suitable coaxial input, provided that the temperature is entered manually or recorded separately. Its robust, straightforward design also makes the electrode particularly suitable for training and teaching environments, where electrodes often have to withstand frequent changes of hands and less careful handling.Typical applicationsAccording to WTW, the SenTix 21 pH electrode is suitable for, amongst other things:Electroplating effluent and industrial wastewaterAquarium and swimming pool waterGroundwater, lake water, surface water and seawaterHousehold cleaning products and general wastewater samplesStorage and shelf lifeBetween two measurements, the measuring chain should ideally remain immersed in reference electrolyte (3 mol/l KCl, Ag⁺-free). Overnight or during longer breaks, the clean electrode should be placed in the wetting cap filled with reference electrolyte; storing it in a dry place or in deionised water will cause permanent damage to the membrane. Once the irrigation cap has dried out, the measuring chain requires at least 24 hours of conditioning in fresh reference electrolyte before it can measure reliably again. WTW classifies pH measuring chains as consumables: strong acids and alkalis, hydrofluoric acid, organic solvents, oils, fats and high temperatures further reduce their service life.Distinctions within the SenTix familyWithin the WTW electrode range, the SenTix 21 differs from the SenTix 41 (item no. 103635), which uses the same plastic shaft and the same gel electrolyte but also features an NTC temperature sensor and a DIN connector with banana plugs. Those wishing to use automatic temperature compensation on the measuring instrument are better served by the SenTix 41. For more demanding requirements regarding media and measurement range, for example, in pharmaceutical analysis or for samples up to 100 °C, the SenTix 81 glass electrode (item no. 103642) is the more suitable choice.Design and response behaviourThe fibre diaphragm forms the interface between the reference electrolyte and the sample solution. It is less susceptible to blockages than a ceramic diaphragm and is therefore also suitable for samples containing suspended solids or organic residues, such as those found in waste water or aquarium water. WTW does not specify a precise numerical response time for the SenTix 21, either on the product page or in the user manual; in practice, however, it remains sufficiently short for routine measurements of this type.A common example is checking a swimming pool or aquarium: the electrode is briefly immersed, provides the measurement value on the spot, and can then be reinserted into the protective cap without any further preparation for the next use.Technical detailsTypePlastic-shaft electrode (epoxy/PPE-PS), gel electrolyte, low-maintenanceDiaphragmFibreShaft materialPlastic (PPE/PS), cylindrical diaphragm shapeElectrolyteGel, non-refillablepH measurement range0…14 pHTemperature range0…80 °CTemperature sensorNoneDiaphragm resistance< 1 GOhmConnection1 m fixed cable with BNC connector (coaxial connector to DIN 19262)Shaft length / shaft diameter120 mm / 12 mmStandardsCE (Declaration of Conformity for SenTix/TA-Sensolyt analogue pH electrodes), DIN 19262 (coaxial connector)Scope of delivery1 WTW SenTix 21 pH electrode with hydration cap fittedOperating instructions available for downloadIndividual requirements and procurement serviceFor calibration, the WTW technical buffer solutions pH 4.01 (item no. 108706) and pH 7.00 (item no. 108708) from the same manufacturer are suitable. If you require further accessories, replacement electrodes or have any questions regarding the appropriate SenTix model, the LT Laborhandel procurement service is available at lt-laborhandel.com/service.
WTW Standard (DIN/NIST) Buffer Solution PL 7, pH 6.865/6.87, PTB/NIST-traceable Calibration Solution in Accordance with DIN 19266-01:2000, ± 0.02 pH, 250 ml, 109120
An electrode that is incorrectly calibrated in the neutral range will introduce a bias into every subsequent measurement, particularly where pH 7, as the zero point of the scale, plays a key role. The WTW Standard (DIN/NIST) buffer solution PL 7 provides a traceable reference for this purpose: a working reference buffer solution in accordance with DIN 19266-01:2000, certified as traceable to PTB/NIST, with an accuracy of ± 0.02 pH at 25 °C. Together with PL 4 and PL 9, it forms the midpoint of a complete, documentable three-point calibration. Standard (DIN/NIST) buffer solution PL 7: higher accuracy class than the technical range The key difference from the ‘technical’ WTW buffer solution range lies in the accuracy class and traceability. The WTW Technical Buffer Solution pH 7 is designed for daily routine calibration and reliably covers everyday laboratory work. The Standard (DIN/NIST) Buffer Solution PL 7 goes one step further: As a working reference buffer solution in accordance with DIN 19266-01:2000, it is certified as PTB/NIST-traceable and specified to ± 0.02 pH at 25 °C. This makes it the ideal choice wherever the calibration itself must be documented and traceable, such as in ISO/IEC 17025-accredited testing laboratories, in pharmaceutical analysis or in metrologically demanding research. Buffer system comprising two phosphate salts PL 7 is based on a mixture of disodium hydrogen phosphate and potassium dihydrogen phosphate as a buffer system and achieves a pH value of 6.87 at 20 °C, stated on the label as pH 6.865 according to DIN or pH 6.87 according to NIST. The density is 1.01 g/cm³, the melting point is -0.3 °C and the boiling point is 100 °C. Under the CLP Regulation, the solution is not classified as a hazardous substance and is not a dangerous good, which simplifies storage, transport and handling in day-to-day laboratory work. Each bottle bears its own batch code with an expiry date, ensuring that the batch used can always be linked to the corresponding test certificate and remains clearly traceable within the documentation of a quality management system. Traceability as part of quality assurance Traceability means that the printed pH value can be traced back through an unbroken chain of reference measurements to the national metrology institutes PTB and NIST. For a testing laboratory accredited to ISO/IEC 17025, this is precisely the difference between a plausible and a robust measurement: not only the electrode itself, but also the reference used to calibrate it, must be documented and traceable. The zero point at pH 7, in particular, affects the entire calibration curve, which is why a traceable, certified buffer is especially important at this point. With PL 7, this requirement can be met directly via the batch identification and the associated test certificate, without the need for additional in-house verifications in the laboratory. Storage and handling Storage in the tightly sealed original container at 15 to 25 °C is recommended. According to TRGS 510, the solution is classified in storage class LGK 12 (non-flammable liquids) and is not considered to pose a risk to water. As PL 7 is neither classified as a hazardous substance nor declared as dangerous goods, no special protective measures are required when opening or dispensing it. Nevertheless, safety goggles with side protection are recommended for the safe handling of the reference solution, and the container should be resealed promptly after use to prevent the reference value from shifting due to evaporation or the absorption of CO2 from the air. Typical applications PL 7 is used wherever the calibration of a pH electrode must not only be ‘adequate’ but also verifiable through documentation: Two- or three-point calibration of pH electrodes in the neutral measuring range, in conjunction with the WTW buffer solutions PL 4 and PL 9 Zero-point adjustment of the pH scale as the central reference point for every calibration routine Traceable calibration in accredited testing laboratories in accordance with ISO/IEC 17025 Quality control in pharmaceutical and active ingredient analysis Calibration prior to the analysis of approximately neutral samples, such as drinking water or cell culture media Research institutions with stringent requirements regarding measurement uncertainty Buffer solutions in accordance with DIN 19266-01:2000 are among the most widely used working reference buffer solutions, as their composition is specified directly in the standard. When PL 7 is used in conjunction with PL 4 and PL 9 for a three-point calibration, this trio covers the entire pH range relevant to practical applications, from acidic through neutral to alkaline, with the same accuracy class and the same traceability to PTB/NIST. This simplifies documentation, as all three calibration points can be included in the same test certificate format. Technical details Trade namePL 7 Buffer systemDisodium hydrogen phosphate, potassium dihydrogen phosphate pH value at 20 °C6.87 (labelling: pH 6.865 according to DIN / pH 6.87 according to NIST) Accuracy± 0.02 pH at 25 °C TraceabilityPTB/NIST StandardDIN 19266-01:2000 Density at 20 °C1.01 g/cm³ Melting point/freezing point-0.3 °C Boiling point100 °C Physical state / Colour / OdourLiquid, colourless, odourless Hazard classification (CLP)Not classified Dangerous goodsNo Storage class (TRGS 510)Class 12 (non-flammable liquids) Recommended storage temperature15-25 °C Container size250 ml Scope of delivery 1 bottle of WTW Standard (DIN/NIST) buffer solution PL 7, 250 ml, with batch number and expiry date Individual requirements and procurement service For a complete three-point calibration, we also stock the WTW Standard (DIN/NIST) buffer solutions PL 4 (pH 4.006/4.01) and PL 9 (pH 9.180/9.18). If you carry out daily routine calibration using the technical accuracy class, you will find the WTW Technical Buffer Solution pH 7 with the same pH value in our range. You can find suitable pH electrodes for calibration in our range of electrodes. Our procurement service is on hand to assist you with additional accessories for your pH measurement technology or with individual procurement enquiries.
Content: 250 ml (€11.60 / 100 ml)
WTW Technical Buffer Solution pH 7, Calibration Standard Series, (50 ml – 1000 ml)
WTW Technical Buffer Solution pH 7 (108802, 108702, 108708), defined as a high-precision electrochemical calibration standard, provides the metrological foundation for the validation of pH measurement chains in pharmaceutical analysis, biotechnology research and industrial quality assurance. In chemical metrology, a pH value of 7.00 represents the electrical zero point (isopotential point) of most commercially available pH electrodes. From a physico-chemical perspective, the effectiveness of this buffer solution is based on a precisely balanced phosphate buffer system consisting of dihydrogen phosphate (H₂PO₄⁻) and hydrogen phosphate (HPO₄²⁻). This system utilises chemical equilibrium to neutralise external acidic or basic influences, thereby maintaining the hydrogen ion activity at a constant level over a wide range. For procurement professionals in the pharmaceutical industry and research, the reliability of this zero point is an essential prerequisite for investment security, as it forms the basis for the linear calculation of the slope across the entire measurement range. Thermodynamics of ion activity and temperature coefficients The thermodynamics of the WTW Technical Buffer Solution pH 7 are characterised by a strictly defined temperature dependence of the dissociation constant. As the pH value is physically defined as the negative decimal logarithm of the H+ activity, changes in temperature affect the chemical equilibrium via the kinetic energy of the system. The TEP 7, TPL 7 and STP 7 variants feature a detailed temperature table, printed on the label, covering the range from 0 °C to 95 °C. This metrological precision is of fundamental importance for modern pH metres with automatic temperature compensation (ATC) in order to calculate the Nernst factor physically correctly and minimise measurement uncertainty. In industrial process analysis, where measurements are often taken far from the standard temperature of 25 °C, this documented temperature coefficient guarantees the full traceability of results to national primary standards. Variant-specific kinetics and application profiles (STP, TPL, TEP) The range of container sizes – 50 ml (STP 7), 250 ml (TPL 7) and 1000 ml (TEP 7) – allows for specific adaptation to the respective laboratory kinetics and sample throughput. The STP 7 variant (108708), supplied in a 50 ml bottle, is ideally designed for mobile field use or for laboratories with low throughput, in order to minimise the time the opened container is left open and thus the risk of carbonation due to atmospheric CO₂. The standard 250-ml TPL 7 (108802) is the universal workhorse for daily routine calibration in university education and research. For high-throughput environments in pharmaceutical production, the 1-litre variant TEP 7 (108702) offers a highly efficient solution for supplying automated calibration stations. Each variant is subject to the same stringent electrochemical specifications, enabling easy scaling of laboratory processes without compromising analytical integrity. Material science of the barrier layer and storage stability A critical quality attribute of the WTW Technical Buffer Solution pH 7 is the chemical composition of the storage containers. The bottles are made of high-density polyethylene (HDPE), which provides an excellent diffusion barrier against atmospheric gases. The ingress of carbon dioxide would physically shift the pH value into the acidic range via the formation of carbonic acid (H₂CO₃), which would lead to significant calibration errors, particularly in the neutral pH range. The stabilised matrix of the WTW buffer solutions also prevents microbiological growth without altering the surface tension of the electrode’s glass membrane. For pharmaceutical buyers, this long-term stability is a key factor in reducing TCO (Total Cost of Ownership), as the solutions exhibit a metrological drift of less than 0.01 pH units over their entire service life, provided that the handling instructions are followed. Electrochemical metrology and compliance in quality assurance Finally, the use of the WTW Technical Buffer Solution pH 7 ensures compliance with the highest regulatory standards, such as GMP, GLP and ISO 17025. When calibrating a measuring chain, the buffer solution is used to determine the asymmetry voltage. The use of technical buffers in accordance with DIN 19267 ensures a high degree of comparability of measured values between different laboratory sites. The solution’s optimised ionic strength reduces the electrode’s response time, which enhances efficiency, particularly in diagnostics and time-critical process controls. By choosing the WTW buffer series, laboratories are investing in a tried-and-tested system solution that harmonises physical excellence with the practical requirements of modern quality management. Technical Details Thermodynamics & Chemical Specifications Nominal pH value (at 25 °C): 7.00 Measurement uncertainty: ± 0.03 pH Buffer system: Phosphate buffer (based on KH₂PO₄ / Na₂HPO₄) Temperature range: 0 °C to 95 °C (with documented table of values) Kinetics: Rapid potential stabilisation through optimised ionic conductivity Metrology & Control Engineering Conformity: Complies with the requirements for technical buffers in accordance with DIN 19267 Traceability: Directly traceable to NIST / PTB primary standards Calibration function: Determination of zero point and asymmetry voltage Stability: Microbiologically stabilised, CO₂-inhibited Materials Science & Variants – Dimensions Container material: High-density polyethylene (HDPE) with barrier properties Variant STP 7 (108708): 50 ml bottle (ideal for field use) Variant TPL 7 (108802): 250 ml bottle (standard size for routine use) Variant TEP 7 (108702): 1000 ml bottle (for high-volume use/automation) Environmental conditions & storage Storage temperature: 15 °C to 25 °C (recommended) Shelf life: Typically 24 months from date of manufacture (depending on batch) Physical state: Liquid, odourless, pH-neutral Contents 1 x WTW Technical Buffer Solution pH 7 (in the selected variant: 50 ml, 250 ml or 1000 ml) 1 x temperature correction table (printed on the label) Important note: Buffer solutions are consumables. To ensure metrological integrity, solution that has been removed must never be returned to the original container. The use of a separate beaker for calibration is physically essential. Individual requirements & accessories For a complete two-point calibration, in addition to the WTW Technical Buffer Solution pH 7, a second standard (e.g. pH 4.01 TPL 4 or pH 10.01 TPL 10) is required to determine the slope of the electrode. For the maintenance of your pH sensors, we also recommend WTW cleaning solutions (e.g. RL 1 for protein removal) and a 3-molar KCl solution for the proper storage of the reference systems. All supplementary standards and maintenance kits are available via our procurement service.
Content: 250 ml (€6.84 / 100 ml)
WTW Technical Buffer Solution TPL 4, 1 bottle of 250 ml: pH 4.01, #108800
WTW Technical Buffer Solution TPL 4, 1 bottle of 250 ml: pH 4.01, #108800
Content: 250 ml (€6.80 / 100 ml)
WTW TFK 150 Temperature Probe for Automatic Temperature Compensation, 1 m Cable, 102274
The WTW TFK 150 is a temperature sensor for pH or redox electrodes that do not have their own sensor. It supplies the measuring instrument with the sample temperature for automatic temperature compensation.Temperature during calibration and measurementFor redox and ISE measurements, the probe is also used for compensation. Like the electrode, it is immersed in the sample and should be rinsed along with the sample before each new measurement.Cable and connectorThe sensor is fitted with a 1 m long fixed cable with a waterproof connector. We would be happy to check whether the temperature input on your measuring instrument is compatible with the TFK 150 before you place your order.Where the TFK 150 is usedThe probe is designed for automatic temperature compensation during pH, redox and ISE measurements. It also serves as an external probe for conductivity cells and the D 300/pH flow cell. The SenTix 60 pH electrode does not have its own temperature sensor, nor does the SenTix 22. The SenTix 42, for example, features a probe integrated directly into the shaft.Typical applicationsAutomatic temperature compensation for pH, redox and ISE measurementsExternal temperature probe for conductivity cells and the D 300/pH flow-through cellTechnical detailsTypeTemperature sensor (NTC) for automatic temperature compensationCable1 m fixed cable with waterproof connectorScope of delivery1 WTW TFK 150 temperature probe with 1 m cableIndividual requirements and procurement serviceA probe usually requires a suitable electrode, and the correct combination depends on the measuring instrument. The procurement service at lt-laborhandel.com/service can help with selection and ordering.
WTW Technical Buffer Solution TEP 10 Trace, 1 bottle containing 1 L: pH 10.01, #108703
WTW Technical Buffer Solution TEP 10 Trace, 1 bottle containing 1 L: pH 10.01, #108703
Content: 1000 ml (€4.60 / 100 ml)
WTW Standard (DIN/NIST) Buffer Solution PL 4, pH 4.006/4.01, PTB/NIST-traceable Calibration Solution in Accordance with DIN 19266-01:2000, ± 0.02 pH, 250 ml, 109110
Anyone calibrating a pH electrode in an accredited testing laboratory, in pharmaceutical quality control or in research cannot do without a fully traceable reference. The WTW Standard (DIN/NIST) buffer solution PL 4 delivers exactly that: a working reference buffer solution in accordance with DIN 19266-01:2000, which is certified as traceable to both the PTB and NIST and achieves an accuracy of ± 0.02 pH at 25 °C. It thus covers the acidic range of the pH scale and, together with the WTW buffer solutions PL 7 and PL 9, forms the basis for a complete, documentable three-point calibration. Standard (DIN/NIST) buffer solution PL 4: higher accuracy class than the technical range The key difference from the ‘technical’ WTW buffer solution range lies in the accuracy class and traceability. Technical buffer solutions are designed for the daily routine calibration of pH electrodes and reliably cover everyday laboratory work. The Standard (DIN/NIST) buffer solution PL 4 goes one step further: As a working reference buffer solution in accordance with DIN 19266-01:2000, it is certified as PTB/NIST-traceable and specified to ± 0.02 pH at 25 °C. This makes it the ideal choice wherever the calibration itself must be documented and traceable, for example in ISO/IEC 17025-accredited testing laboratories, in pharmaceutical analysis or in metrologically demanding research. Buffer system: potassium hydrogen phthalate PL 4 is based on potassium hydrogen phthalate as the buffer system and achieves a pH value of 4 at 20 °C, stated on the label as pH 4.006 according to DIN or pH 4.01 according to NIST. Its density is 1.01 g/cm³, its melting point is -1.6 °C and its boiling point is 100 °C. Under the CLP Regulation, the solution is not classified as a hazardous substance and is not a dangerous good, which simplifies storage, transport and handling in day-to-day laboratory work. Each bottle bears its own batch code with an expiry date, so that the batch used can be linked to the corresponding test certificate at any time and remains clearly traceable within the documentation of a quality management system. Traceability as part of quality assurance Traceability means that the printed pH value can be traced back through an unbroken chain of reference measurements to the national metrology institutes PTB and NIST. For a testing laboratory accredited to ISO/IEC 17025, this is precisely the difference between a plausible and a robust measurement: not only the electrode itself, but also the reference against which it was calibrated, must be documented and traceable. With PL 4, this requirement can be met directly via the batch identification and the associated test certificate, without the need for additional in-house verifications in the laboratory. Storage and handling Storage in the tightly sealed original container at 15 to 25 °C is recommended. According to TRGS 510, the solution is classified in storage class LGK 12 (non-flammable liquids), is not classified as hazardous to water and, according to the safety data sheet, is considered readily biodegradable. As PL 4 is neither classified as a hazardous substance nor declared as dangerous goods, no special protective measures are required when opening or dispensing it. Nevertheless, for safe handling of the reference solution, safety goggles with side protection are recommended, and the container should be resealed promptly after use to prevent the reference value from shifting due to evaporation or the absorption of CO2 from the air. Typical applications PL 4 is used wherever the calibration of a pH electrode must not only be ‘adequate’ but also verifiable through documentation: Two- or three-point calibration of pH electrodes in the acidic measurement range, in conjunction with the WTW buffer solutions PL 7 and PL 9 Traceable calibration in accredited testing laboratories in accordance with ISO/IEC 17025 Quality control in pharmaceutical and active ingredient analysis Calibration prior to the analysis of acidic samples, such as fruit juices, wine or soil extracts Research institutions with stringent requirements regarding measurement uncertainty Buffer solutions in accordance with DIN 19266-01:2000 are among the most widely used working reference buffer solutions, as their composition is specified directly in the standard. When PL 4 is used in conjunction with PL 7 and PL 9 for a three-point calibration, this trio covers the entire pH range relevant to practical applications, from acidic through neutral to alkaline, with the same accuracy class and the same traceability to PTB/NIST. This simplifies documentation, as all three calibration points can be included in the same test certificate format. Technical details Trade namePL 4 Buffer systemPotassium hydrogen phthalate pH value at 20 °C4 (labelled: pH 4.006 according to DIN / pH 4.01 according to NIST) Accuracy± 0.02 pH at 25 °C TraceabilityPTB/NIST StandardDIN 19266-01:2000 Density at 20 °C1.01 g/cm³ Melting point/freezing point-1.6 °C Boiling point100 °C Physical state / Colour / OdourLiquid, colourless, odourless Hazard labelling (CLP)Not classified Dangerous goodsNo Storage class (TRGS 510)Class 12 (non-flammable liquids) Recommended storage temperature15-25 °C Container size250 ml Scope of delivery 1 bottle of WTW Standard (DIN/NIST) buffer solution PL 4, 250 ml, with batch number and expiry date Individual requirements and procurement service For a complete three-point calibration, we also stock the WTW Standard (DIN/NIST) buffer solutions PL 7 (pH 6.865/6.87) and PL 9 (pH 9.180/9.18). If you carry out daily routine calibration using the technical accuracy class, you will find the WTW Technical Buffer Solution TPL 4 with the same pH value in our range. You can find suitable pH electrodes for calibration in our range of electrodes. Our procurement service is on hand to assist you with additional accessories for your pH measurement technology or with individual procurement enquiries.
Content: 250 ml (€11.60 / 100 ml)
WTW SenTix ORP Redox Electrode with Platinum Sensing Element, Liquid Electrolyte, S7 Connector, 103648
The SenTix ORP from WTW is a redox electrode with a platinum measuring element for laboratory use. The measuring element is a platinum disc with a diameter of 4 mm; the shaft is made of glass. The reference system is Ag/AgCl in 3 mol/l KCl (Ag⁺-free), which can be refilled. The electrode does not have a temperature sensor and is supplied without a connection cable.Configuration of the redox measurement chainThe potential between the platinum disc and the Ag/AgCl reference system is measured. A ceramic diaphragm is situated between the reference electrolyte and the sample. The electrode is 120 mm long with a shaft diameter of 12 mm and is approved for use between 0 and 100 °C. It is supplied with a water-sealing cap fitted, which is also used for storage.S7 plug head and connection cableThe connector is an S7 plug; the cable is supplied separately. The input on the measuring instrument determines which cable is suitable: S7/DIN 1 m (item no. 108110), S7/DIN 3 m (item no. 108112) or S7/BNC 1 m (item no. 108114). These same cables are also used with pH electrodes featuring an S7 connector, such as the SenTix 60.Converting measured values to the standard hydrogen electrodeThe meter displays the voltage relative to the Ag/AgCl system. To reference the standard hydrogen electrode, UH = UMeas + URef. URef depends on the temperature and, for the SenTix ORP, is, for example, +224 mV at 0 °C, +207 mV at 25 °C and +180 mV at 60 °C. The full table can be found in the operating instructions; see also DIN 38404-6. As the electrode does not have its own temperature sensor, the sample temperature must be known separately.Refilling, Storage, CleaningDuring measurement, the refill opening must be open, and the electrolyte level should be at least 2 cm above the level of the sample. If the level drops, top up with KCl-250 (item no. 109705), for example using a dropper bottle. During short breaks in measurement, the measuring chain should be left standing in the reference electrolyte; overnight, it should be placed in the filled wetting cap with the refill opening closed. Grease and oil can be removed with water containing washing-up liquid; limescale and hydroxide deposits with 10 per cent citric acid; and proteins with the pepsin cleaning solution PEP/pH (item no. 109648) for about an hour. Redox measuring chains are consumables. Strong acids and alkalis, hydrofluoric acid, organic solvents, oils, fats, bromides, sulphides, iodides, proteins, high temperatures and sharp changes in temperature or pH shorten their service life.Typical applicationsRedox measurement in the laboratory (ORP measurement) in aqueous samples up to 100 °CChecking the measuring chain with redox buffer solution RH 28 (UH = 427 mV, 250 ml, item no. 109740)For argentometry, the same series includes the SenTix Ag with a silver measuring element and a different electrolyte (KNO3 with a small amount of KCl). Those measuring redox potentials use the ORP with platinum. For argentometry, the Ag is used.Technical detailsTypeRedox electrode with liquid electrolyteSensing elementPlatinum, 4 mm discShaft materialGlassDiaphragmCeramicReference system / electrolyteAg/AgCl, KCl 3 mol/l, Ag⁺-free, refillableTemperature sensorNoneTemperature range0…100 °CShaft length / shaft diameter120 mm / 12 mmConnectionS7 plug-in connector, without connection cableScope of delivery1 WTW SenTix ORP redox electrode with irrigation capThe scope of delivery does not include connection cables, which must be ordered separately.Individual requirements and procurement serviceConnection cables in the required length, reference electrolyte, redox buffer solution, cleaning solution or the STH 650 bench stand (item no. 109809): You can enquire about these items together with the electrode via lt-laborhandel.com/service. The procurement service will also clarify whether ORP or Ag is suitable for the measurement task.
WTW SenTix H analogue special-purpose pH electrode, ground-glass diaphragm, S7 connector, 103644
The WTW SenTix H analogue special-purpose pH electrode is a sophisticated, premium-class electrochemical system solution designed specifically for high-precision measurements in the extremely high-alkalinity range and in sample media with very high salt concentrations. In traditional applications within the chemical industry, electroplating or the monitoring of industrial effluents, conventional standard electrodes often suffer from the so-called alkalinity error (sodium error) or blockages of the diaphragm. The SenTix H eliminates these sources of process error whilst minimising damage to the material, thanks to a highly specialised membrane glass formulation and mechanically optimised reference system kinetics. The system deliberately omits an integrated temperature sensor to ensure maximum robustness and thermal service life in demanding electrochemical applications. Specialised glass to counteract the alkali error and for high salt concentrations The material architecture of the sensor is uncompromisingly designed for extreme pH ranges. The sensitive membrane glass is characterised by excellent selectivity, which reliably minimises measurement errors caused by high concentrations of sodium ions in strongly alkaline environments. A tried-and-tested liquid electrolyte (3 mol/l KCl) serves as the reference system; this can be easily topped up or completely replaced via a sealable opening at the top of the glass shaft. This guarantees consistently high ionic activity and excellent reproducibility of measurement results, even during continuous use in aggressive chemical media. Controlled electrolyte outflow via an adjustable ground diaphragm An outstanding design feature of the SenTix H is the integrated ground diaphragm. Compared with conventional ceramic or fibre diaphragms, the precisely ground glass core enables a comparatively high, continuous and precisely defined electrolyte flow. These flow dynamics prevent sample components from entering the reference system and, without damaging the material, rule out blockages caused by crystallisation or salt precipitation. The ground diaphragm can be easily cleaned and reactivated as required, which drastically extends the sensor’s service life in multi-user operation and guarantees a fast, stable response. Extended geometry and flexible S7 plug-in head The physical boundary of the system is defined by a robust glass shaft, which, with a special length of 165 mm, allows deep immersion into necked flasks, reactors, deep sample vessels or laboratory apparatus. The mechanical and electrical connection to the pH meter is made via the standardised S7 connector. As no fixed cable is fitted, the electrode can be operated with a high degree of flexibility using various cable types (e.g. S7 to DIN or S7 to BNC). This protects the delicate glass probe from mechanical stress caused by cable tension and enables the sensor to be replaced easily within the existing measurement setup without the need to re-route the entire cable infrastructure. Technical details Measurement & Sensor Technology Sensor type: Special analogue pH electrode Model: SenTix H pH measurement range: 0 to 14 pH (optimised for the high-alkali range) Temperature element: Without integrated temperature sensor Operating temperature range: 0 to 100 degrees Celsius Construction & dimensions Shaft material: Highly chemically resistant glass shaft Shaft length: 165 mm (extended version) Shaft diameter: 12 mm Electrolyte: Liquid electrolyte (3 mol/l KCl, refillable) Diaphragm: Adjustable ground diaphragm Connection head: S7 plug-in head (without fixed connection cable) Geometry: Cylindrical glass membrane Operating conditions Maintenance: Refillable (KCl liquid replaceable) Main applications: Strongly alkaline media, high salt concentrations, electroplating, process monitoring, deep laboratory vessels Scope of delivery 1 x WTW SenTix H analogue special-purpose pH electrode (MPN: 103644) 1 x humidification cap with KCl storage solution 1 x pipette vial with refill electrolyte (3 mol/l KCl) 1 x Quality certificate / Quick start guide Important note: A suitable S7 connection cable (e.g. AS/DIN or AS/BNC), calibration buffers and the pH meter itself are not included in the standard scope of delivery and must be ordered separately. Customised requirements & accessories To ensure the full performance capabilities of the WTW SenTix H in highly alkaline matrices, we stock a comprehensive range of connection components and consumables. For connection to the meter, we offer genuine WTW laboratory cables with an S7 connector head fitted to a DIN or BNC plug. For regular recalibration in the critical alkaline range, we recommend certified WTW technical buffer solutions (in particular pH 9.18 and pH 10.01) in handy dosing bottles. The use of genuine 3 mol/l KCl solution is essential for the regular refilling of the reference system and for the material-friendly storage of the ground diaphragm during measurement breaks. Please make use of our technical procurement service to tailor your industrial test setup to your specific requirements.
WTW SenTix 20 Plastic PH Electrode with Gel Electrolyte, S7 Connector, 103630
The WTW SenTix 20 is a plastic pH electrode with a gel electrolyte and an S7 connector. It is supplied without a cable. The length and plug of the connection cable can therefore be adapted to the existing measuring instrument.Shaft, membrane and gelThe shaft is made of PPE/PS, is 120 mm long and has a diameter of 12 mm. The membrane is cylindrical; the diaphragm is made of fibre, and a gel serves as the reference system. The membrane resistance is less than 1 GΩ, the pH measurement range extends from 0 to 14 pH and the permissible temperature range is from 0 to 80 °C. The manufacturer specifies this range for outdoor use.Select the cable as requiredDepending on the measuring instrument, the S7 connector head accommodates one of three WTW connection cables: AS/DIN, 1 m (order no. 108110), AS/DIN-3, 3 m (108112) or AS/BNC, 1 m (108114). The electrode does not have its own temperature sensor.Commissioning and storageBefore taking the first measurement, remove the wetting cap; shake the device to remove any air bubbles behind the membrane. During short measurement breaks, the measuring chain should be kept in reference electrolyte (3 mol/l KCl, Ag⁺-free); overnight, it should be stored in the wetting cap filled with this solution. Storing the electrode in a dry state or in deionised water can cause permanent damage; if the cap dries out, the manufacturer recommends at least 24 hours of conditioning. Strong acids and alkalis, hydrofluoric acid, organic solvents, oils, fats and proteins shorten the service life, as is the case with any pH measuring chain.When another SenTix model is a better fitFor those wishing to measure temperature and pH with a single measuring chain, the SenTix 41-3 features an integrated NTC sensor on a 3 m fixed cable. For measurements up to 100 °C in a glass shaft, the SenTix 81 is the alternative. The SenTix 20 is suitable where gel, plastic and a freely selectable cable are sufficient.Typical applicationsElectroplating effluent, industrial effluent and effluent in generalAquarium water and swimming pool waterGroundwater, lake water, surface water and seawaterHousehold cleaning productsTechnical detailsTypePlastic pH electrode with gel electrolyteSensor shapeCylinderShaft materialPlastic (PPE/PS)Shaft length / Shaft diameter120 mm / 12 mmDiaphragmFibreReference systemGelpH measurement range0 to 14 pHTemperature range0 to 80 °CMembrane resistance< 1 GΩTemperature sensorNoneConnectionS7 plug-in connector, without connection cableStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix 20 pH measuring chain with rinsing capConnection cable not included, available separatelyIndividual requirements and procurement serviceOur procurement service is available to assist with the correct S7 connection cable, KCl-250 reference electrolyte (order no. 109705) for the rinsing cap, buffer solutions for calibration or any other SenTix model. The operating instructions for the measuring chain describe calibration and maintenance in detail. We would be happy to advise you in advance on which cable is suitable for your measuring instrument.
WTW SenTix 51 PH Electrode with Liquid Electrolyte and Temperature Sensor, Plastic Shaft, 1 m Cable, 103651
The WTW SenTix 51 has a plastic shaft and a reference electrolyte that can be topped up via a refill port. A ceramic diaphragm is used. It also features an NTC sensor in the shaft and a 1 m long fixed cable.Refillable system with ceramic diaphragmThe reference system consists of reference electrolyte (3 mol/l KCl, Ag⁺-free). Due to the way it works, a small amount flows from the reference system through the diaphragm into the sample during operation; if the level drops too low, it can be topped up via the refill port. The supplied dropper bottle is intended for this purpose. During calibration and measurement, the refill port remains open, and the electrolyte level should be at least 2 cm above the sample level.Shaft and connectorThe shaft is made of polyamide and measures 120 x 12 mm. The 1 m long fixed cable has a waterproof DIN plug and a 4 mm banana plug. The manufacturer classifies the SenTix 51 to 57 series as suitable for field use. The SenTix 81 is suitable for measurements up to 100 °C in a glass shaft.pH and temperature in a single measuring chainThe integrated NTC 30 kOhm sensor supplies the measuring instrument with the sample temperature for automatic compensation. The pH measurement range is from 0 to 14; the permissible temperature range is 0 to 80 °C, and the membrane resistance is less than 1 GΩ. If your instrument has a BNC connector instead of a DIN connector, you will find the same model as the SenTix 52.Preparation, storage and cleaningBefore the first measurement, open the filling port, remove the rinsing cap and shake the measuring chain to dispel any air bubbles behind the membrane. For overnight storage, place the electrode in the wetting cap filled with reference electrolyte and close the refill opening. A pepsin cleaning solution removes protein-containing deposits, whilst water containing washing-up liquid removes grease and oil. After each cleaning, the electrode must be conditioned for at least one hour and recalibrated.Typical applicationsDrinking water, mineral water and aquarium waterSwimming pool waterLake water, surface water and seawaterFruit juice, vegetable juice and wineTechnical detailsTypepH electrode with liquid electrolyte and temperature sensorSensor designCylinderShaft materialPlastic (polyamide)Shaft length / Shaft diameter120 mm / 12 mmDiaphragmCeramicReference systemKCl 3 mol/l, Ag⁺-free, refillablepH measuring range0 to 14 pHTemperature range0 to 80 °CMembrane resistance< 1 GΩTemperature sensorNTC 30 kOhm, integratedConnection1 m fixed cable with waterproof DIN plug and 4 mm banana plugStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix 51 pH measuring chain with rinsing cap1 dropper bottle with reference electrolyte for refillingIndividual requirements and procurement serviceReplenishment of KCl-250 reference electrolyte (order no. 109705), PEP/pH pepsin cleaning solution (109648), buffer solutions and the plastic reinforcement A pHLab/K are available on request. Our procurement service is available to assist with further SenTix models and selection based on the measuring instrument.
WTW SenTix Sur PH Surface Electrode with Flat Membrane, Glass Shaft, S7 Connector, 103646
The WTW SenTix Sur features a flat membrane for surface measurements, for example on gel, bacterial cultures or leather. It is placed on the moist sample and measures the pH value there, without the need to transfer the sample into a container.Flat membrane and annular gap diaphragmThe sensor is flat in shape; the shaft is made of glass, is 120 mm long and has a diameter of 12 mm. An open annular gap serves as the diaphragm, whilst the reference system (Referid) consists of a polymer filling with a lifetime of service. The electrolyte therefore does not need to be topped up. The membrane resistance is less than 1 GΩ.Keeping an eye on the measuring rangeAt 2 to 13 pH, the measuring range is narrower than that of many other SenTix models; the permissible temperature range is 0 to 50 °C. For strongly acidic or strongly alkaline solutions in the vessel, an electrode with a measuring range of 0 to 14 pH, such as the SenTix 20, is the better choice.Cable and temperatureThe S7 connector head is supplied without a connection cable. You can choose between AS/DIN versions with 1 m (order no. 108110) and 3 m (108112), as well as AS/BNC versions with 1 m (108114). A temperature sensor is not fitted. For penetration measurements in semi-solid samples, WTW offers its own model, the SenTix Sp.Storage and careThe irrigation cap is used for storage. During measurement breaks, the electrode is immersed in reference electrolyte (3 mol/l KCl, Ag⁺-free); overnight, it is placed in the cap filled with this solution. Storing the electrode in a dry place or using deionised water can cause permanent damage to the membrane. The membrane should not rub against the bottom of the container, otherwise it will become scratched. Water containing washing-up liquid dissolves grease and oil; limescale deposits can be removed with citric acid.Typical applicationsHair gel, make-up, lotions and creamsAgar-agar gel and bacterial culturesLeather, paper and skinSurface measurement on damp samplesTechnical detailsTypepH surface electrodeSensor shapeFlatShaft materialGlassShaft length / Shaft diameter120 mm / 12 mmDiaphragmRing gap (open diaphragm)Reference systemReferid (lifetime polymer filling)pH measurement range2 to 13 pHTemperature range0 to 50 °CMembrane resistance< 1 GΩTemperature sensorNoneConnectionS7 plug-in connector, without connection cableStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix Sur pH measuring chain with irrigation capConnection cable not included, available separatelyIndividual requirements and procurement serviceConnection cables for the S7 plug-in head, KCl-250 reference electrolyte (order no. 109705) for the rinsing cap and buffer solutions for calibration are available on request via LT Laborhandel. Our procurement service can answer any questions regarding the sample and the appropriate electrode type.
WTW TFK 325 Temperature Probe for Aqueous Solutions, 1 m Cable, 102280
The pH value of a sample depends on its temperature, and electrodes without their own sensor do not indicate this temperature. This is what the WTW TFK 325 is designed for. It measures the temperature in aqueous solutions and transmits it to the measuring instrument, which then automatically compensates for it.Why the probe is necessaryThe slope of a pH measuring chain changes with temperature. A measuring instrument can only compensate for this effect if it knows the sample temperature. The temperature of the sample should therefore be measured at the point where the electrode is located, and the sensor must be immersed in the sample.Design and connectionThe sensor has a 1 m long fixed cable with a waterproof connector, so there is no need to purchase a separate cable. You should check before ordering whether the temperature input on your meter is compatible with the TFK 325.For electrodes without their own temperature sensorAutomatic temperature compensation is used for pH, redox and ISE measurements. An example: The SenTix 62, for instance, is a glass electrode without a temperature sensor. The SenTix ORP redox electrode also does not have a sensor. The TFK 150 is also available from the same sensor range.Typical applicationsAutomatic temperature compensation for pH, ORP and ISE measurements in aqueous solutionsExternal temperature probe on conductivity cells and on the D 300/pH flow-through cellTechnical detailsTypeTemperature sensor (NTC) for automatic temperature compensationTest mediumaqueous solutionsCable1 m fixed cable with waterproof plugScope of delivery1 WTW TFK 325 temperature probe with 1 m cableIndividual requirements and procurement serviceYou can check whether the temperature input on your measuring instrument is compatible with the TFK 325 before placing your order. Please direct any enquiries regarding this or suitable pH electrodes to the procurement service at lt-laborhandel.com/service.
WTW SenTix 52 PH Electrode with Liquid Electrolyte and Temperature Sensor, Plastic Shaft, BNC Connector, 1 m Cable, 103652
The WTW SenTix 52 has a 1 m fixed cable with a BNC plug and a 4 mm banana plug, as well as a built-in NTC sensor. The shaft is made of plastic, and the electrolyte system is refillable.Electrolyte and diaphragmThe SenTix 52 is supplied ex-works with a reference electrolyte consisting of 3 mol/l KCl, Ag⁺-free. It flows slowly into the sample via a ceramic diaphragm and can be topped up via the refill port. The dropper bottle for this purpose is supplied with the electrode. This measuring chain does not feature a gel system as found on the SenTix 42. Consequently, the refill port is a maintenance point that must remain open during calibration and measurement.Shaft, probe and measuring rangeThe 120 mm long shaft, with a diameter of 12 mm, is made of polyamide. The 30 kOhm NTC sensor is housed within the shaft and enables automatic temperature compensation. Measurements are taken from 0 to 14 pH between 0 and 80 °C with a membrane resistance of less than 1 GΩ. For samples up to 100 °C, the SenTix 82 glass electrode is available, also featuring an NTC sensor, BNC and banana plugs.The DIN variant in comparisonWith all other measurement data being the same, the plastic electrode with a DIN connector is available as the SenTix 51. Which of the two is suitable depends solely on the input on the measuring instrument.Operation and storageThe wetting cap is removed before measurement and kept for storage. Gas bubbles behind the membrane are removed by shaking. Overnight or for longer periods, the measuring chain is placed in the cap filled with reference electrolyte, and the refill opening is sealed. Storage in a dry environment or in deionised water will cause permanent damage to the electrode. If the cap has dried out, the measuring chain must be left in the reference electrolyte for at least 24 hours.Typical applicationsDrinking water and mineral waterAquarium water and swimming pool waterLake water, surface water and seawaterFruit juice, vegetable juice and wineTechnical detailsTypepH electrode with liquid electrolyte and temperature sensorSensor designCylinderShaft materialPlastic (polyamide)Shaft length / shaft diameter120 mm / 12 mmDiaphragmCeramicReference systemKCl 3 mol/l, Ag⁺-free, refillablepH measurement range0 to 14 pHTemperature range0 to 80 °CMembrane resistance< 1 GΩTemperature sensorNTC 30 kOhm, integratedConnection1 m fixed cable with BNC plug and 4 mm banana plugStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix 52 pH measuring chain with rinsing cap1 dropper bottle with reference electrolyte for refillingIndividual requirements and procurement serviceReference electrolyte KCl-250 (order no. 109705), pepsin cleaning solution PEP/pH (109648), buffer solutions for calibration and the A pHLab/K plastic reinforcement are available on request. Our procurement service can assist you in choosing between BNC, DIN and other connector types.
WTW SenTix 62 Glass PH Electrode with Liquid Electrolyte, Refillable, BNC, 1 m Cable, 103641
The WTW SenTix 62 is a glass electrode with a conical membrane, a platinum wire diaphragm and a refillable liquid electrolyte (KCl 3 mol/l, Ag+-free). It measures pH from 0 to 14 at temperatures ranging from 0 to 100 °C. It does not have a temperature sensor.Glass shaft, conical membrane, platinum wire diaphragmThe glass shaft is 120 mm long with a diameter of 12 mm; the membrane resistance is less than 600 MΩ. The 1 m long fixed cable is fitted with a BNC connector. The electrode is designed for laboratory use. Between measurements, it should be rinsed with the next solution or with deionised water and carefully dabbed dry to ensure no solution is carried over. The frequency of recalibration depends on the application.With or without a temperature sensorIf you wish to measure temperature automatically, choose the SenTix 82. It has the same design but features an NTC sensor. The SenTix 60 is available with an S7 connector head instead of a fixed cable, in which case the cable must be selected separately. If you are working without a sensor, for the 62 you will need either the temperature from a second measurement or a separate temperature sensor.Topping up the electrolyteThe measuring cell is filled at the factory. Before use, the refill port is opened and remains open during calibration and measurement. The electrolyte level should be at least 2 cm above the level of the sample. If it drops, top up with reference electrolyte; the easiest way is to use the dropper bottle supplied: cut the tip straight across, press it into the refill port and pump the electrolyte into the shaft.Storage and cleaningDuring short breaks, the electrode should be left standing in the reference electrolyte with the refill opening open. Overnight, it should be placed in the filled rinsing cap, with the refill opening closed. If stored dry or in deionised water, it will suffer permanent damage. For protein contamination, soak in Pepsin cleaning solution PEP/pH (item no. 109648) for about an hour; for grease and oil, use water containing washing-up liquid; for limescale, use a 10 per cent citric acid solution. Afterwards, condition the electrode in reference electrolyte for at least one hour and recalibrate it.Typical applicationsDrinking water, mineral water, groundwater, lake water, surface water and seawater, swimming pool waterBeer, lemonade, fruit juice, vegetable juice, wine, milk, coffee extract and vinegarSoil extracts, paper extracts and salt solutionsDiluted acids, emulsions, suspensions, cooling water, dye solutions and electroplating bathsHair dye, mouthwash and household cleanersEnzyme solutions, gastric juice, infusion solutions, serum, Tris buffer solutions, urine and other protein-containing liquidsAccessories: Reference electrolyte KCl-250 (item no. 109705), WTW buffer solutions, plastic arm A pHLab/K (item no. 903841) and STH 650 bench stand (item no. 109809).Technical detailsTypeGlass pH electrode with liquid electrolyteSensor shapeConeShaft materialGlassDiaphragmPlatinum wireElectrolyteKCl 3 mol/l, Ag⁺-free, refillablepH measurement range0…14 pHTemperature range0…100 °CTemperature sensorNoneDiaphragm resistance< 600 MΩShaft length / shaft diameter120 mm / 12 mmConnection1 m fixed cable with BNC connectorComplianceEU Declaration of Conformity EU139 (RoHS Directive 2011/65/EU, EN IEC 63000:2018)Scope of delivery1 WTW SenTix 62 pH electrode with rinsing capDropper bottle with reference electrolyte for refillingIndividual requirements and procurement serviceElectrolyte, buffer solutions, cleaning solution or an electrode with a different connection: contact lt-laborhandel.com/service to enquire about the right product, even if you do not yet know which SenTix model is compatible with your measuring instrument.
WTW SenTix 60 Glass PH Electrode with Liquid Electrolyte, S7 Connector, 120 mm, 103639
The WTW SenTix 60 is the laboratory electrode from the SenTix 60 to 62 series, in the version with an S7 plug-in head. It features a glass shaft with a conical membrane, a platinum wire diaphragm and a refillable reference electrolyte. The temperature range extends up to 100 °C; a connection cable is not included in the scope of delivery.Glass, conical diaphragm, platinum wireThe shaft and diaphragm are made of glass; the shaft is 120 mm long and has a diameter of 12 mm. The platinum wire diaphragm is situated at the lower end of the shaft. The diaphragm resistance is less than 600 MΩ. It is intended for laboratory use. Gas bubbles behind the diaphragm are not a problem with this type; shaking before measurement is not necessary.Refilling and measurementThe measuring chain is filled with reference electrolyte (3 mol/l KCl, Ag⁺-free) at the factory. The refill port remains open during calibration and measurement. The dropper bottle included in the scope of delivery is used for topping up when the level in the shaft drops. The electrolyte level should be at least 2 cm above the sample level; the diaphragm must be completely submerged.Cables and temperature sensorsThe S7 connector head allows you to select the connection cable to suit the instrument: AS/DIN with 1 m (order no. 108110) or 3 m (108112) and AS/BNC with 1 m (108114). The SenTix 60 does not have a built-in temperature sensor. If you require one in the shaft, choose the SenTix 81 with an integrated NTC sensor. The SenTix 62 is a measuring chain with a fixed cable and BNC connector, without a sensor.Media and LimitationsTypical media range from diluted acids through emulsions and suspensions to food samples and protein-containing liquids. Proteins can be removed after measurement using a pepsin cleaning solution. Hydrofluoric acid, hot phosphoric acid and strong alkaline solutions will destroy the glass membrane. The measuring chain must not be stored dry or in deionised water.Typical applicationsDiluted acids, emulsions and suspensionsCooling water, dye solutions, electroplating baths, paper extract and salt solutionsDrinking water, groundwater, swimming pool water, lake water, surface water and seawater, soil extractBeer, lemonade, fruit juice, vegetable juice, wine, mineral water, milk, coffee extract and vinegarHair dye, mouthwash and household cleanersEnzyme solutions, gastric juice, infusion solutions, serum, Tris buffer solutions and urineTechnical detailsTypeGlass pH electrode with liquid electrolyteSensor shapeConeShaft materialGlassShaft length / Shaft diameter120 mm / 12 mmDiaphragmPlatinum wireReference systemKCl 3 mol/l, Ag⁺-free, refillablepH measurement range0 to 14 pHTemperature range0 to 100 °CMembrane resistance< 600 MΩTemperature sensorNoneConnectionS7 plug-in head, without connection cableStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix 60 pH measuring chain with rinsing cap1 dropper bottle with reference electrolyte for topping upConnection cable not included; available separatelyIndividual requirements and procurement serviceThe AS/DIN, AS/DIN-3 and AS/BNC, KCl-250 reference electrolyte (order no. 109705), PEP/pH pepsin cleaning solution (109648) and buffer solutions are supplied by LT Laborhandel on request. Our procurement service will advise you on which cable is suitable for your measuring instrument.
WTW Standard (DIN/NIST) Buffer Solution PL 9, pH 9.180/9.18, PTB/NIST-traceable Calibration Solution in Accordance with DIN 19266-01:2000, ± 0.02 pH, 250 ml, 109130
In the alkaline measuring range, a pH electrode requires the same traceable calibration point as in the acidic and neutral ranges. The WTW Standard (DIN/NIST) buffer solution PL 9 provides a working reference buffer solution in accordance with DIN 19266-01:2000, certified as traceable to PTB/NIST, with an accuracy of ± 0.02 pH at 25 °C. It thus complements PL 4 and PL 7 as the third point in the three-point calibration. Unlike the other two stages in the range, PL 9 also requires hazardous substance labelling; please refer to the separate section below. Standard (DIN/NIST) buffer solution PL 9: higher accuracy class than the technical range The key difference from the ‘technical’ WTW buffer solution range lies in the accuracy class and traceability. Technical buffer solutions are designed for daily routine calibration and reliably cover everyday laboratory work. The Standard (DIN/NIST) buffer solution PL 9 goes one step further: As a working reference buffer solution in accordance with DIN 19266-01:2000, it is certified as PTB/NIST-traceable and specified to ± 0.02 pH at 25 °C. This makes it the ideal choice wherever the calibration itself must be documented and traceable, such as in ISO/IEC 17025-accredited testing laboratories, in pharmaceutical analysis or in metrologically demanding research. Traceability as part of quality assurance Traceability means that the printed pH value can be traced back through an unbroken chain of reference measurements to the national metrology institutes PTB and NIST. For a testing laboratory accredited to ISO/IEC 17025, this is precisely the difference between a plausible and a robust measurement: not only the electrode itself, but also the reference against which it was calibrated, must be documented and traceable. With PL 9, this requirement can be met directly via the batch identification and the associated test certificate, without the need for additional in-house verifications in the laboratory. Buffer system: disodium tetraborate decahydrate (borax) PL 9 is based on disodium tetraborate decahydrate (borax, CAS 1303-96-4, concentration 0.3-<1 % in the mixture) as a buffer system and achieves a pH value of 9.18 at 20 °C, stated on the label as pH 9.180 according to DIN or pH 9.18 according to NIST. The density is 1 g/cm³, the melting point is 0 °C, the boiling point is 100 °C, and the dynamic viscosity at 20 °C is 0.952 mPas. Each bottle bears its own batch code with an expiry date, ensuring that the batch used can be linked to the corresponding test certificate at any time and remains clearly traceable within the documentation of a quality management system. Hazard labelling in accordance with GHS/CLP Unlike PL 4 and PL 7, PL 9 is classified as Repr. 1B under Regulation (EC) No 1272/2008 due to its content of disodium tetraborate decahydrate. The labelling comprises the hazard pictogram GHS08, the signal word ‘Danger’ and the hazard statement H360FD: ‘May impair fertility. May cause harm to the unborn child.’ Precautionary statements: P280 (Wear protective gloves/protective clothing/eye protection/face protection), P308+P313 (If exposed or affected: seek medical advice/attention) and P405 (keep locked up). The hazard-determining ingredient, disodium tetraborate decahydrate (CAS 1303-96-4), is also listed as a substance of very high concern (SVHC) in accordance with Article 57 of REACH, although it is present in the mixture only in a concentration of 0.3 to less than 1 per cent. The product is intended exclusively for professional users. Before use, refer to the safety data sheet, in particular the information on protective equipment and first-aid measures. Storage and handling It is recommended to store the product in the original, tightly sealed container at 15 to 25 °C, kept under lock and key in accordance with P405. According to TRGS 510, the solution is assigned to storage class LGK 6.1D, in contrast to storage class LGK 12 for the unclassified PL 4 and PL 7. For handling, the safety data sheet recommends protective gloves made of nitrile rubber with a material thickness of at least 0.11 mm and a breakthrough time of 480 minutes, as well as safety goggles with side protection. Respiratory protection is only required if aerosols or mists form. The product is non-flammable and is not classified as a dangerous good under the relevant transport regulations (ADR/RID/ADN/IMDG/IATA). Typical applications PL 9 is used wherever the calibration of a pH electrode in the alkaline range must not only be ‘adequate’ but also verifiable through documented evidence: Two- or three-point calibration of pH electrodes in the alkaline measuring range, in conjunction with the WTW buffer solutions PL 4 and PL 7 Traceable calibration in accredited testing laboratories in accordance with ISO/IEC 17025 Quality control in pharmaceutical and active ingredient analysis Calibration prior to the analysis of alkaline samples, such as cleaning solutions or certain process waters Research institutions with stringent requirements regarding measurement uncertainty Buffer solutions in accordance with DIN 19266-01:2000 are among the most widely used working reference buffer solutions, as their composition is specified directly in the standard. When PL 9 is used in conjunction with PL 4 and PL 7 for a three-point calibration, the trio covers the entire pH range relevant to practical applications, from acidic through neutral to alkaline, with the same accuracy class and the same traceability to PTB/NIST. As PL 9 is the only one of the three grades to be classified as a hazardous substance, care should be taken to note the different storage class, LGK 6.1D, when ordering and storing the calibration set together. Technical details Trade namePL 9 Buffer systemDisodium tetraborate decahydrate (borax), CAS 1303-96-4, concentration 0.3-<1 % pH value at 20 °C9.18 (labelled: pH 9.180 according to DIN / pH 9.18 according to NIST) Accuracy± 0.02 pH at 25 °C TraceabilityPTB/NIST StandardDIN 19266-01:2000 Density at 20 °C1 g/cm³ Melting point/freezing point0 °C Boiling point100 °C Dynamic viscosity at 20 °C0.952 mPas Physical state / Colour / OdourLiquid, colourless, odourless Classification (CLP)Repr. 1B Hazard pictogramGHS08 Hazard statementDanger Hazard statement (H-phrase)H360FD: May impair fertility. May harm the unborn child. Precautionary statements (P-phrases)P280, P308+P313, P405 SVHC listing (REACH Art. 57)Yes, disodium tetraborate decahydrate, CAS 1303-96-4 Dangerous goodsNo Storage class (TRGS 510)LGK 6.1D Recommended storage temperature15-25 °C Container size250 ml Scope of delivery 1 bottle of WTW Standard (DIN/NIST) buffer solution PL 9, 250 ml, with batch number and expiry date Individual requirements and procurement service For complete three-point calibration, we also stock the WTW Standard (DIN/NIST) buffer solutions PL 4 (pH 4.006/4.01) and PL 7 (pH 6.865/6.87). For the alkaline range of the technical accuracy class, we also stock the WTW Technical Buffer Solution TPL 10 Trace (pH 10.01). You will find suitable pH electrodes for calibration in our range of electrodes. Our procurement service is on hand to assist you with additional accessories for your pH measurement technology or with individual procurement enquiries.
Content: 250 ml (€11.60 / 100 ml)
WTW SenTix 41-3 Plastic PH Electrode with Gel Electrolyte and Temperature Sensor, 3 m Cable, 103636
The WTW SenTix 41-3 measures pH and temperature using a single measuring chain. An NTC sensor with a resistance of 30 kOhm is housed in the shaft; the signal is transmitted together with the pH signal via a 3 m long fixed cable to the measuring instrument. The connector consists of a waterproof DIN plug and a 4 mm banana plug.Why the integrated sensor mattersThe pH value of a solution depends on its temperature, and the slope of the electrode changes accordingly. Instruments with automatic temperature compensation read the temperature directly from the shaft, without the need to suspend a second probe in the vessel. The version without a sensor, but with the same shaft and gel system, is the SenTix 21-3.Shaft, gel and diaphragmThe plastic shaft, made of PPE/PS, is 120 mm long and 12 mm in diameter. The diaphragm is made of fibre, with a gel serving as the reference system. The pH measurement range is from 0 to 14, the temperature range from 0 to 80 °C, and the membrane resistance is less than 1 GΩ.Cable and connectorA three-metre fixed cable is sufficient for measuring stations where there is some distance between the sample and the instrument. If a one-metre cable is sufficient and you require BNC connectors, consider the SenTix 42. On the SenTix 41-3, the cable terminates in a DIN plug in accordance with DIN 19262 and a 4 mm banana plug.MaintenanceBefore use, remove the rinsing cap; gas bubbles behind the membrane are removed by shaking. During short measurement breaks, the electrode should be stored in reference electrolyte (3 mol/l KCl, Ag⁺-free); overnight, it should be stored in the filled rinsing cap. Once the cap has dried out, the measuring chain must be conditioned in the reference electrolyte for at least 24 hours. Following cleaning, the electrode must be conditioned for at least one hour and recalibrated. A shorter service life is to be expected when used in fats, oils, protein solutions or strong acids and alkalis.Typical applicationsElectroplating effluent, industrial effluent and effluent in generalAquarium water and swimming pool waterGroundwater, lake water, surface water and seawaterHousehold cleaning productsTechnical detailsTypePlastic pH electrode with gel electrolyte and temperature sensorSensor shapeCylinderShaft materialPlastic (PPE/PS)Shaft length / Shaft diameter120 mm / 12 mmDiaphragmFibreReference systemGelpH measurement range0 to 14 pHTemperature range0 to 80 °CMembrane resistance< 1 GΩTemperature sensorNTC 30 kOhm, integratedConnection3 m fixed cable with waterproof DIN plug and 4 mm banana plugStandardsEU Declaration of Conformity (RoHS Directive 2011/65/EU), WEEE markingScope of delivery1 WTW SenTix 41-3 pH measuring chain with irrigation cap and fixed 3 m cableIndividual requirements and procurement serviceReference electrolyte KCl-250 (order no. 109705), buffer solutions for calibration and the A pHLab/K plastic armour are among the WTW accessories supplied by LT Laborhandel on request. Our procurement service is available to assist with other cable lengths, connector combinations or any queries regarding the pin configuration on the measuring instrument.
WTW SenTix Top 41 PEEK PH Electrode with Temperature Sensor, Low-maintenance, 1 m Cable, 103816
The WTW SenTix Top 41 has a PEEK shaft, a polymer electrolyte and a perforated diaphragm. The temperature range is from -5 to 100 °C; an NTC sensor with a resistance of 30 kOhm is housed within the shaft.PEEK shaft and polymer electrolyteThe shaft is 120 mm long and has a diameter of 12 mm; the measurement range is from 0 to 14 pH. The diaphragm is perforated, the electrolyte is a polymer, and the electrode is considered low-maintenance. It is designed for outdoor and process measurements.Cable with waterproof DIN connectorThe Top 41 has a 1 m fixed cable with a waterproof DIN plug (coaxial plug to DIN 19262) and a 4 mm banana plug. A separate S7 cable is not required. If your measuring instrument has a BNC input, the SenTix 42 with BNC and banana plugs is a more suitable option, although it uses a gel electrolyte and is only suitable up to 80 °C. If you are looking for a glass-sheathed probe with a polymer electrolyte and a temperature sensor, the SenTix RJD is the right choice.Typical applicationsDiluted acids and alkalis, emulsions and suspensionsSulphide-containing liquids, cooling water, dyeing solutions and electroplating bathsCutting oil emulsions, electroplating effluent and industrial wastewaterSwimming pool water, waste water, groundwater, lake water, surface water and seawaterHair dye, lotions and creams, mouthwash and toothpasteHoney, jam, mayonnaise and vinegarEmulsion paints, as well as water-soluble paints and varnishesCommissioning, storage and cleaningBefore the first measurement, remove the wicking cap. Keep it, as it is needed for storage. Gas bubbles behind the diaphragm can be removed by shaking. The diaphragm at the lower end of the shaft must be fully immersed in the sample; only the shaft is immersed. During measurement breaks, the electrode should be kept in reference electrolyte (3 mol/l KCl, Ag⁺-free); overnight, it should be stored in the cap filled with this solution. Grease and oil can be removed with water containing washing-up liquid, whilst limescale and hydroxide deposits can be removed with 10 per cent citric acid; in both cases, contact time should be kept as short as possible. Hydrofluoric acid, hot phosphoric acid and strong alkalis destroy the glass membrane. Like any pH measuring chain, the Top 41 is a consumable item, and high temperatures or sharp fluctuations in temperature and pH shorten its service life.Calibration and accessoriesCalibration is carried out in accordance with the meter’s instructions, under stirring conditions similar to those used during measurement. The probe should be immersed vertically or at a slight angle. WTW buffer solutions (DIN/NIST and technical) are suitable for calibration. These are complemented by the A pHLab/K plastic armature (item no. 903841), the STH 650 bench stand (item no. 109809) and the KCl-250 reference electrolyte (item no. 109705) for storage.Technical detailsTypepH electrode with temperature sensor, low-maintenanceSensor shapeCylinderShaft materialPEEKDiaphragmHoleElectrolytePolymerpH measurement range0…14 pHTemperature range-5…100 °CTemperature sensorNTC 30 kOhm, integratedShaft length / shaft diameter120 mm / 12 mmConnection1 m fixed cable with waterproof DIN plug (coaxial plug to DIN 19262) and 4 mm banana plugsConformityEU Declaration of Conformity EU139 (RoHS Directive 2011/65/EU, EN IEC 63000:2018)Scope of delivery1 WTW SenTix Top 41 pH electrode with irrigation capIndividual requirements and procurement serviceBuffer solutions, a stand and mounting bracket are supplied with the electrode. The procurement service will be happy to clarify in advance whether the Top 41 is suitable for a specific sample at lt-laborhandel.com/service.
WTW SenTix ORP-T 900 digital IDS redox electrode, glass shaft, 1.5 m fixed cable, 103791
The WTW SenTix ORP-T 900 digital IDS redox electrode is a highly advanced electrochemical system solution for the precise determination of the oxidation-reduction potential (ORP) and temperature in laboratories, research institutes and industrial process control. Designed for use with modern WTW IDS multi-parameter analysers, this digital platinum electrode enables error-free signal transmission and comprehensive documentation in accordance with strict quality standards. In demanding electrochemical analyses, corrosion studies or the monitoring of detoxification and neutralisation processes, the elimination of signal interference caused by long cable runs is the primary criterion for guaranteeing high-precision measurements whilst minimising damage to the material. Intelligent IDS sensor technology and digital signal processing The mechatronic system architecture of the SenTix ORP-T 900 is based on innovative IDS (Intelligent Digital Sensors) technology. Unlike conventional analogue redox probes, the sensitive analogue voltage signal is digitised and calibrated directly within the internal sensor assembly. This transient signal processing completely eliminates electromagnetic interference, such as that which may be induced by surrounding laboratory equipment, motors or stirring drives. An integrated data memory permanently stores the sensor’s specific serial number and calibration history. This guarantees maximum process reliability and seamless GLP compliance for every measurement. High-purity platinum sensor technology and refillable reference system The material design is consistently optimised for maximum precision and chemical resilience. The electrode features a chemically highly resistant glass shaft that remains stable even in aggressive media. The actual sensor element consists of a high-purity platinum tip, which ensures excellent electron transfer and fast response times. A tried-and-tested liquid electrolyte containing 3 mol/l KCl serves as the reference system; this can be easily topped up or completely replaced via a sealable opening at the top of the glass shaft. In combination with the precise ceramic diaphragm, a constant electrolyte flow is ensured, which drastically reduces the risk of diaphragm blockages and significantly extends the sensor’s service life in multi-user operation. Integrated temperature compensation and process-reliable fixed cable connection To ensure thermodynamically correct measurement results, the SenTix ORP-T 900 features a built-in 30 kOhm NTC temperature sensor, which is integrated directly into the electrode tip and enables precise real-time correlation of the measured redox potential with the sample temperature. The connection to the IDS measuring instrument is via a permanently fitted, 1.5-metre-long cable with a waterproof, digital IDS connector. This fixed cable connection offers optimum mechanical protection against the ingress of splash water and moisture and guarantees uninterrupted signal transmission as well as convenient handling at the laboratory workstation or directly at the plant. Technical details Measurement & Sensor Technology Sensor type: Digital IDS redox electrode (ORP) Model: SenTix ORP-T 900 Redox measurement range: -1250 to +1250 mV Sensor element: High-purity platinum (platinum cup) Temperature element: Integrated 30 kOhm NTC temperature sensor Operating temperature range: 0 to 100 °C Construction & dimensions Shaft material: Chemically highly resistant glass shaft Electrolyte: Liquid electrolyte (3 mol/l KCl, refillable) Diaphragm: Ceramic diaphragm Shaft length: 120 mm Shaft diameter: 12 mm Connection type: Fixed cable, length 1.5 m with digital IDS plug Serial number: Stored electronically within the sensor Operating conditions Maintenance: Refillable (KCl liquid replaceable) Main applications: Chemical analysis, electroplating baths, environmental measurement technology, wastewater monitoring, research Contents 1 x WTW SenTix ORP-T 900 digital IDS redox electrode with 1.5 m fixed cable (MPN: 103791) 1 x storage cap with KCl storage solution 1 x pipette vial with refill electrolyte (3 mol/l KCl) 1 x Quality certificate / Quick start guide Important note: Redox test solutions, cleaning concentrates and the IDS measuring instrument itself are not included in the standard scope of delivery and must be ordered separately. Individual requirements & accessories To realise the full potential of the WTW SenTix ORP-T 900, we recommend using it with a compatible WTW MultiLine or inoLab IDS meter. To enable regular checking and verification of the metrological chain, we stock certified WTW redox test solutions (e.g. 180 mV, 430 mV or 475 mV). For regular refilling and the proper storage of the platinum tip, we recommend original 3 mol/l KCl solution. Please make use of our technical procurement service to put together your digital measuring station.