WTW digital IDS pH electrode SenTix 945, glass shaft, 1.5 m fixed cable, 103743

Drinking water, beer, fruit juice and wine are on the media list that WTW names for the SenTix 945. The electrode has a glass shaft and a gel electrolyte that is not refilled. As an IDS sensor, it stores the sensor type, serial number and calibration data itself, and the measuring instrument retrieves them on connection. It measures from 0 to 14 pH at sample temperatures of 0 to 80 °C.

What WTW names the SenTix 945 for

According to WTW, the electrode is suitable for these media, among others:

• Drinking water, mineral water, lake water, surface water and seawater
• Beer, lemonade, fruit juice, vegetable juice, wine, coffee extract and vinegar
• Dilute acids, salt solutions, bleach solution, emulsions and suspensions
• Soil extract, hair dye and household cleaners
• Enzyme solutions, gastric juice, infusion solutions, protein-containing liquids, serum, Tris buffer solutions and urine

WTW lists the last group under pharma, biology and medicine. This is an application category and not a statement on suitability for medical devices.

Spherical membrane and three ceramic junctions

The membrane is spherical. For this, WTW cites a constant measuring quality and, thanks to the large surface, a low resistance, below 600 MΩ according to the product page. Three ceramic junctions provide the electrolyte contact. The glass shaft is 120 mm long and has a diameter of 12 mm. An NTC temperature sensor (30 kΩ) is built in, and the electrode is low-maintenance. According to WTW, the IDS electronics work with an accuracy of pH ±0.004, ±0.2 mV, ±0.1 °C (±1 digit in each case).

Connection

The SenTix 945 has a permanently attached cable of 1.5 m with a waterproof IDS plug (4-pin, lockable). The versions 945 and 945-P have the same electrode; the difference lies solely in the connection.

Cap, storage and cleaning

The wetting cap stays on until the measurement; afterwards, gas bubbles behind the membrane are shaken out. The electrode is stored in the cap with reference electrolyte (KCl 3 mol/l, Ag+-free), never dry and never in deionised water. If the cap has run empty, the electrode is conditioned in reference electrolyte for at least 24 hours. According to WTW, salt deposits on the cap do not affect the measuring properties and can be removed with deionised water. Hydrofluoric acid, hot phosphoric acid and strongly alkaline solutions destroy the glass membrane.

Technical details

Scope of delivery

• 1 WTW SenTix 945 pH electrode with wetting cap
• Operating instructions
• Fixed cable 1.5 m with IDS plug, permanently attached to the electrode

Regulatory information

As an electrical device, the digital IDS electrode falls under the ElektroG. The manufacturer Xylem Analytics Germany GmbH (WTW brand) is registered under the WEEE registration number DE 29884659. How to return old appliances is described on the page Environment and disposal.

Accessories and procurement service

Also available are reference electrolyte KCl 3 mol/l for the wetting cap and buffer solutions for calibration. If you need a different version, please enquire via the procurement service.