WTW SenTix Micro 900-P digital IDS pH microelectrode, Ø 5 mm, 103765

The WTW SenTix Micro 900-P 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 use 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-P 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 sensor’s universal connector head. 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 (Quality Sensor Control) function, the sensor continuously assesses its current status 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 slim 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 refilled or 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 low viscosity.

Integrated temperature sensor and universal plug-in connectivity

To ensure thermodynamically correct analyses, the SenTix Micro 900-P 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. An outstanding ergonomic feature of this variant is the universal IDS plug-in connector. The sensor does not have a permanently attached cable; instead, it can be connected to the measuring station with great flexibility, either via an AS IDS connection cable or completely wirelessly via a WTW radio module. This protects the delicate glass system from mechanical stress caused by cable tension and improves the user’s freedom of movement in confined laboratory workstations.

Technical details

Measurement & Sensor Technology

• Sensor type: Digital IDS pH microelectrode
• Model: SenTix Micro 900-P
• 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 head: Universal IDS plug-in head (for AS IDS cable or wireless module)
• Serial number: Stored electronically within the sensor

Operating conditions

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

Contents

• 1 x WTW digital IDS pH microelectrode SenTix Micro 900-P (MPN: 103765)
• 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: The required IDS connection cable (e.g. AS IDS-1.5), wireless modules, pH buffer solutions 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-P’s full range of functions, we recommend operating it with a compatible WTW MultiLine or inoLab IDS measuring instrument. For the mechanical connection, we stock the suitable AS IDS-1.5 cable as well as innovative IDS wireless module systems for cable-free operation. 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 and pH 10.01). For regular refilling and the proper storage of the sensitive glass membrane, we recommend the original 3 mol/l KCl solution. Please use our procurement service to put together your digital micro-measurement station.