WTW SenTix Micro 900 digital IDS pH microelectrode, Ø 5 mm, 1.5 m fixed cable, 103751

The WTW SenTix Micro 900 digital IDS pH microelectrode is a specialised, electrochemical system solution for high-precision pH measurement in minimal sample volumes and confined vessel geometries. Designed for demanding applications in biomedical, pharmaceutical and chemical research laboratories, this digital probe enables reliable, process-safe operation directly in NMR tubes, Eppendorf cups or delicate culture vessels. When analysing valuable or rare sample media, reducing the minimum required volume whilst simultaneously eliminating signal interference is the primary criterion for ensuring reproducible measurement results whilst minimising damage to the sample material. The system is fully validated for WTW IDS multi-parameter analysers and supports modern GLP and GMP documentation processes.

Intelligent IDS sensor technology and digital measurement stability

The mechatronic system architecture of the SenTix Micro 900 is based on innovative IDS (Intelligent Digital Sensors) technology. The highly sensitive analogue voltage signal from the measuring chain is digitised and calibrated directly within the internal sensor assembly. This transient signal processing completely eliminates sources of electromagnetic interference, such as those that may be induced by surrounding laboratory equipment or stirrer drives. An internal data memory permanently stores the electrode’s specific serial number as well as a complete history of the last 10 calibrations. Via the integrated QSC function (Quality Sensor Control), the sensor continuously assesses its current condition and displays this directly on the screen of the connected measuring instrument, which significantly enhances the validity of each individual test step.

Delicate glass shaft and refillable liquid delivery system

The materials-science-based design is consistently optimised for requirements in the microlitre range. With an extremely slender shaft diameter of just 5 mm, the electrode allows deep, non-contact immersion into the narrowest of sample vessels. 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. In combination with a precise platinum wire diaphragm, a defined, constant electrolyte flow is achieved. This guarantees a rapid response from the pH-sensitive glass membrane and prevents diffusion potentials and measurement drifts, even in media with low ion content or those that are slightly viscous.

Integrated temperature sensor and process-reliable fixed cable connection

To ensure thermodynamically correct analyses, the SenTix Micro 900 features a built-in 30 kOhm NTC temperature sensor, which is integrated directly into the sensor tip and performs 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 or moisture in confined laboratory workstations, prevents accidental cable disconnections during the measurement series and ensures uninterrupted signal transmission.

Technical details

Measurement & Sensor Technology

• Sensor type: Digital IDS pH microelectrode
• Model: SenTix Micro 900
• pH measurement range: 0 to 14 pH
• Temperature element: Integrated NTC 30 kOhm temperature sensor
• Operating temperature range: 0 to 100 °C
• Calibration memory: Integrated memory for up to 10 calibrations
• Sensor evaluation: QSC-compatible (Quality Sensor Control)

Design & dimensions

• Shaft material: Highly chemically resistant glass shaft
• Shaft diameter: 5 mm (optimised for very small volumes)
• Shaft length: 120 mm
• Electrolyte: Liquid electrolyte (3 mol/l KCl, refillable)
• Diaphragm: Platinum wire diaphragm
• Connection type: Fixed cable, length 1.5 m with digital IDS plug
• Serial number: Stored electronically within the sensor

Operating conditions

• Minimum immersion depth: Low (suitable for use in the microlitre and millilitre range)
• Application: NMR tubes, Eppendorf cups, small sample vessels, biotechnology, microanalysis

Contents

• 1 x WTW SenTix Micro 900 digital IDS pH microelectrode with 1.5 m fixed cable (MPN: 103751)
• 1 x rinsing cap with KCl storage solution
• 1 x vial of refill electrolyte (3 mol/l KCl)
• 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 make full use of the WTW SenTix Micro 900’s full range of functions, 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 stock certified WTW technical buffer solutions (pH 4.01, pH 7.00 and pH 10.01). For regular refilling and the proper storage of the sensitive glass diaphragm, we recommend the original 3 mol/l KCl solution. As protein and sample residues can build up on the platinum diaphragm over time, we also stock special cleaning solutions to restore the sensor’s performance. Please use our technical procurement service to put together your digital micro-measurement station.