METHOD OF DETERMINATION OF FLUORIDE ION CONCENTRATION IN WATER (VERSION) Russian patent published in 2008 - IPC G01N27/42 

FIELD: physics.

SUBSTANCE: invention concerns potentiometric methods of determining fluoride ion concentration in water medium. Fluoride ion-selective electrode with solid lanthanum trifluoride membrane is used for measurements. Measurement is performed in solutions with added base electrolyte, which is either 0.01 N solution of pure nitric acid with pH of the measured water medium maintained within 2.0±0.1 units, or 0.01 N solution of pure acetic acid with added complexing agent, that is 0.01 N solution of disodium ethylendiamine tetraacetic acid salt (Trilon B), and pH of the measured water medium maintained within 3.4±0.1 units. Both solutions of base electrolyte allow obtaining high metrological characteristics of fluoride selective electrode for low fluoride ion concentration, thus enabling measurement of low fluoride ion concentration. Due to the last factor the method can be applied in control over highly deionised water with low fluoride ion content at nuclear and thermoelectric power stations and electronic facility plants.

EFFECT: improved control precision.

6 cl, 3 ex, 3 tbl, 5 dwg