WTW analogue precision pH electrode SenTix 91, glass shaft, 170 mm, 103695
€459.00
% Manufacturer's RRP: €509.00 9% below manufacturer's RRP
- Glass shaft 170 mm long, 12 mm in diameter
- Spherical membrane, membrane resistance below 600 MΩ
- Liquid electrolyte KCl 3 mol/l, Ag+-free, refillable
- Platinum wire junction
- Built-in NTC temperature sensor 30 kΩ
- Measuring range 0 to 14 pH, 0 to 100 °C
- 1 m fixed cable with DIN and banana plugs
Product information "WTW analogue precision pH electrode SenTix 91, glass shaft, 170 mm, 103695"
With tall sample vessels, a 120 mm long shaft quickly reaches its limit. The WTW SenTix 91 is an analogue pH electrode with a 170 mm long glass shaft, making it 50 mm longer than the SenTix 81. It features a refillable liquid electrolyte, a platinum wire junction and a built-in NTC temperature sensor. The measuring range extends from 0 to 14 pH at sample temperatures of 0 to 100 °C.
Spherical membrane and platinum wire junction
The membrane of the SenTix 91 is spherical. According to WTW, the large surface area ensures low resistance and consistent measurement quality. The membrane resistance is less than 600 MΩ. The reference electrolyte is 3 mol/l KCl, Ag+-free. The refill opening remains open during calibration and measurement. A dropper bottle is included according to the WTW instructions.
Sensor, cable and plug
The NTC sensor (30 kΩ) measures the sample temperature for temperature compensation. The permanently attached cable is 1 m long. It terminates in a waterproof DIN plug (DIN 19262) for the electrode and a 4 mm banana plug for the sensor. The measuring instrument therefore requires a DIN input and a socket for the sensor.
Typical applications according to WTW
- Food and drink: beer, lemonade, fruit juice, vegetable juice, wine, mineral water, milk, vinegar
- Water: drinking water, groundwater, swimming pool water, lake water, surface water, seawater
- Industry: cooling water, dye solutions, electroplating baths, salt solutions, emulsions, suspensions, diluted acids
- Extracts: soil, paper and coffee extracts
- Cosmetics and household: hair dye, mouthwash, household cleaners
- Pharmaceuticals, biology, medicine: enzyme solutions, gastric juice, infusion solutions, protein-containing liquids, serum, Tris buffer solutions, urine
Storage and care
During short measurement breaks, the electrode should be placed in reference electrolyte (KCl 3 mol/l, Ag+-free) with the refill opening left open. Overnight and for longer periods, it should be placed in the wetting cap containing reference electrolyte, with the refill opening closed. It should not be stored dry or in deionised water, as this can cause permanent damage according to WTW. A dried-out cap requires at least 24 hours of conditioning in reference electrolyte. As with any pH electrode, strong acids and alkalis, hydrofluoric acid, organic solvents, oils, fats and proteins shorten its service life.
Technical details
| Type | pH electrode, analogue, liquid electrolyte |
| Shaft material | Glass |
| Shaft length / Shaft diameter | 170 mm / 12 mm |
| Electrolyte | KCl 3 mol/l, Ag+-free, refillable |
| Junction | Platinum wire |
| Membrane shape | Spherical |
| pH measuring range | 0 to 14 |
| Temperature range | 0 to 100 °C |
| Membrane resistance | < 600 MΩ |
| Temperature sensor | NTC 30 kΩ, built-in |
| Connection | DIN plug (DIN 19262), waterproof, and 4 mm banana plug |
| Cable | 1 m fixed cable |
Scope of delivery
- 1 WTW SenTix 91 pH electrode with wetting cap
- Dropper bottle for refilling (included according to the WTW instructions)
- 1 m fixed cable with DIN and banana plugs, permanently attached to the electrode
Accessories and procurement service
KCl 3 mol/l reference electrolyte and buffer solutions for calibration are also available. If you want to clarify the suitable shaft length for a specific vessel, contact the procurement service.