Potentiometry involves measuring an electrical potential that is related to a component in which someone is interested. For example, many communities fluoridate water supplies to enhance the durability of tooth enamel. One convenient way to measure fluoride concentration is to use an electrode where the potential depends upon the concentration of fluoride. Potentiometric electrodes are usually fast, portable, and do not require extensive training to operate.
The AR 20 meter is a research-grade pH meter capable of a variety of functions including automatic temperature compensation, conductivity, and can accept a newer type of electrode called the ion selective field effect transistor (ISFET).
The touchscreen panel provides access to all operating functions, as well as help screens to assist in operation.
The AB15 Plus is a recent addition to our labs. The AB15 plus has a variety of input and output connections, ISFET capabilities, and automated temperature compensation
We have 2 Corning Model 250 IonAnalyzers. These standard digital pH meters have all of the necessary features to use all of the ion-selective electrodes we have. They are not real fancy, but they are solid workhorses.
In an upper level chemistry lab, students have the capability of constructing their own pH meter and interfacing it to a computer. This homemade meter is based on a high impedance operational amplifier wired as a non-inverting amplifier.
We currently have electrodes
for the following ions:
Students may also construct there own liquid membrane electrode in an upper level chemistry course.
Monitoring: CN, F, S, Cl, NO3 etc., in effluents, and natural waters.
Agriculture: NO3, Cl, NH4, K, Ca, I, CN in soils, plant material, fertilizers and feedstuffs.
Food Processing: NO3, NO2 in meat preservatives.
Salt content of meat, fish, dairy products, fruit juices, brewing solutions.
F in drinking water and other drinks.
Ca in dairy products and beer.
K in fruit juices and wine making.
Corrosive effect of NO3 in canned foods.
Detergent Manufacture: Ca, Ba, F for studying effects on water quality.
Paper Manufacture: S and Cl in pulping and recovery-cycle liquors.
Explosives: F, Cl, NO3 in explosive materials and combustion products.
Electroplating: F and Cl in etching baths; S in anodising baths.
Biomedical Laboratories: Ca, K, Cl in body fluids (blood, plasma, serum, sweat).
F in skeletal and dental studies.
Several Vendors of pH meters and Ion Selective Electrodes