An ion meter is an analytical and electrochemical instrument used to measure the concentration of ions in a solution, using ion electrodes (ISE).
A selective ion electrode is a kind of sensor that allows to test ions in various types of samples, whether environmental, pharmaceutical, biotechnological, food, agricultural, industrial, drinking water, wastewater among others. The most commonly tested ions include ammonia, nitrate, chloride, fluoride, calcium, sodium, potassium, silver, iodide, sulfide, lead, bromine, cadmium, copper and others.
An ion is an atom or group of electrically charged atoms. This molecule may have a positive or negative charge. A cation is an ion with a positive charge and an anion is one with a negative charge (atom or molecule). Ions are formed when a neutral (electrically neutral) atom loses or gains electrons. Anions have more electrons than protons and cations have a higher proton number.