costs from $250
products
pH meters
pH Meters
pH measuring instruments are used mainly in the chemical, pharmaceutical, environmental and food industries. We offer a large selection of different measuring instruments for the determination of pH values in the Analytics shop such as pH meters from Mettler Toledo and high-quality solutions for pH measurement from WTW. The inoLab laboratory devices with IDS pH sensors provide the highest data quality and process signals directly in the sensor.
Measuring instruments with the corresponding cables, electrodes, accessories and adaptors are available, e.g. products from the manufacturer WTW use only DIN plugs and Mettler Toledo BNC plugs which are available in our shop.
Please feel free to contact us if you have any questions.
Quality pH-meters by Mettler-Toledo are available in the Analytics-Shop.
These are used in many different areas. For instance, in industries which require very precise measurement results to maintain hygiene standards, like in the food and beverage industry and fulfilling requirements in wastewater treatments and water purification methods.
pH measurement with glass electrodes
pH meters with glass electrodes are the most commonly used measuring devices. Hence, this electrode is generally known as the "pH-electrode". In this method, the electric potential of the glass electrode is measured which is directly dependent on the H+ ion concentration. The potential difference to the reference electrode resulting from the voltage difference converts into the pH reading. The reference electrode is normally a silver-silver chloride half cell which is joined together with the pH electrode to form a combination electrode
Advantages:
- most common method of pH measurement
Disadvantages:
- only slightly more resilient electric current can be generated, i.d. interference of the measurement by the flow potential is easily possible
- both the zero indicator and the increase must be adjusted before calibration
- the diaphragm may be contaminated or worn out
pH measurement with field effect transistors
This involves using pH meters with ion-sensitive field effect transistors (ISFET).
Advantages:
- pH values are more stable
- add on electronics unit show more consistent results
Disadvantages:
- less number of possible measurement processes (= lifetime)
- relatively unpopular type of pH measurement
pH measurement with hydrogen electrodes
Traditional method of pH measurement with the use of hydrogen electrodes. This technique is based on the pH dependence of the hydrogen potential.
Advantages:
- high mechanical stability
- input resistance (impedance) is very low
- no alkali error
- no acid error
Disadvantages:
- exhibit sensitivity to heavy metal salts (copper, silver, mercury)