pH Meters

pH meters are scientific instruments which measure hydrogen-ion concentrations in a solution and indicate acidity and alkalinity. They measure the difference in electrical potential between a pH electrode and a reference electrode. In appearance, they can be a rod-like glass with a bulb containing the sensor at the bottom which is dipped into the solution. Alternatively, they can be a complex laboratory instrument with computer interfaces and several inputs to adjust for variations in pH levels caused by the ambient temperature. There are various types of pH testers. Pocket-sized and handheld portable meters are suitable for field work and the factory floor. Bench top models are the most accurate while in-line pH transmitters are suitable for process control and harsh environments. Potentiometric pH meters measure the voltage between two electrode and display the result converted into a pH value. The highly specialised holographic pH sensors measure colorimetrically. It is very important to calibrate these meters so they should be dipped into buffers or into a test solution of known pH value. pH meters have applications for both the laboratory and field work. They are used in agriculture, brewing and for checking water quality. In healthcare they ensure solutions are safe when applied to patients or lethal as disinfectants.