What is the principle of ISE?
Principle of ion-selective electrode (I.S.E.) An ideal I.S.E. consists of a thin membrane across which only the intended ion can be transported. The transport of ions from a high conc. to a low one through a selective binding with some sites within the membrane creates a potential difference.
What is ion-selective membrane?
An ion-selective electrode (ISE), also known as a specific ion electrode (SIE), is a transducer (or sensor) that converts the activity of a specific ion dissolved in a solution into an electrical potential. The voltage is theoretically dependent on the logarithm of the ionic activity, according to the Nernst equation.
What is ion-selective electrode used for?
Ion-selective electrodes (ISEs) are very similar in use to pH electrodes. They are used for chloride, potassium, calcium, carbon dioxide/carbonate, oxygen, and a variety of other ions. These methods are particularly suited for field analysis and online measurements.
What are ion-selective electrodes types?
The most common glass membrane ion selective electrode is the pH electrode. Another common one is the sodium selective electrode. Crystalline or solid state membrane electrodes are made from relatively insoluble ionically conducting inorganic salts. These are available in homogeneous and heterogeneous forms.
What is the pH electrode?
pH electrodes are analytical sensors for measuring potential of hydrogen (pH), the negative logarithm of the hydrogen ion activity in solution. The pH value of a substance is directly related to the ratio of the hydrogen ion [H+] and the hydroxyl ion [OH-] concentrations.
What is the meaning of the pH in pH meter?
hydrogen ion activity in
A pH meter is an instrument used to measure hydrogen ion activity in solutions – in other words, this instrument measures acidity/alkalinity of a solution. The degree of hydrogen ion activity is ultimately expressed as pH level, which generally ranges from 1 to 14.
What is liquid based ion-selective electrode?
In chemical analysis: Ion-selective electrodes. Liquid-ion-exchanger electrodes utilize a liquid ion exchanger that is held in place in an inert, porous hydrophobic membrane. The electrodes are selective because the ion exchangers selectively exchange a single analyte ion.
What is solid state membrane?
Solid-state ion-selective electrodes use a solid sparingly soluble, ionically conducting substance, either alone or suspended in an organic polymeric material, as the membrane. One of the ions in the solid generally is identical to the analyte ion; e.g., membranes that are composed of silver sulfide…
Which electrode is used in biosensor?
Clark oxygen electrodes perhaps represent the basis for the simplest forms of amperometric biosensors, where a current is produced in proportion to the oxygen concentration.
Can ion-selective electrodes be used for pH measurements explain?
Ion-selective electrodes (ISEs) are potentiometric sensors that include a selective membrane to minimize matrix interferences. The most common ISE is the pH electrode, which contains a thin glass membrane that responds to the H+ concentration in a solution.
What is pH full form?
The letters pH stand for potential of hydrogen, since pH is effectively a measure of the concentration of hydrogen ions (that is, protons) in a substance. The pH scale was devised in 1923 by Danish biochemist Søren Peter Lauritz Sørensen (1868-1969).
Why KCl is used in pH electrode?
Potassium chloride (KCl) acts as a source of chloride ions for the electrode. The advantage of using KCl for this purpose is that it is pH-neutral. Typically, KCl solutions of concentrations ranging from 3 molar to saturated are used in pH meters.
What is the selectivity of a nitrate electrode?
Nitrate with Chloride The selectivity coefficient of the nitrate electrode for chloride is about 0.0056. in concentrations up to 10 times the nitrate before producing a significant error. Nevertheless, Chloride is a common component in many natural waters and
What are the regulations for nitrates in drinking water?
REGULATIONS In the United States the EPA, under the authority of the Safe Drinking Water Act (SDWA), has set the Maximum Contaminant Level Goal (MCLG) for total nitrate/nitrite at 10.0 mg/L and for nitrite at 1.0 mg/L (measured as nitrogen, N).
What is the MCL for nitrite and nitrogen?
The Agency has also established an MCLG and an MCL of 1 mg/L for nitrite (measured as nitrogen) as well as the 10 mg/L MCL for total nitrate plus nitrite (measured as nitrogen).
What are the sources of nitrates?
Most nitrogenous materials in natural waters tend to be converted to nitrate, so all sources of combined nitrogen, particularly organic nitrogen and ammonia, should be considered as potential nitrate sources. Primary sources of organic nitrates include human sewage and livestock manure, especially from feedlots.