ELECTROCHEMICAL METHOD FOR DETERMINING ARSENIC IN NATURAL OBJECTS Russian patent published in 2006 - IPC G01N27/48 

FIELD: analytical methods.

SUBSTANCE: invention relates to analytical chemistry focused on environmental objects, such as natural waters, suspended materials of rivers and lacks, soil, bottom sediments, and other solid objects, to measure, in particular, levels of arsenic using voltammeric technique. The latter consists in reduction of all forms of arsenic to arsenic hydride using solution composed of water, 3% sodium hydroxide, and 1.5% sodium borohydride, which solution is added in amount 0.2 ml to 10 ml of liquid analytical sample preliminarily acidified with hydrochloric acid to pH below 2, whereupon, in order to extract arsenic, minor amounts of gold quantitatively comparable with arsenic are added to solution and resulting anolyte is accumulated on the surface of graphite electrode at constant cathode potential -0.4 V for 30 sec using gold as arsine collector. Finally, analytical signal in the form of cathode peak is registered at potential -0.41 V under square-wave voltammetry conditions, which signal is linearly dependent on arsenic concentration in the sample.

EFFECT: enabled monitoring of arsenic concentrations within specified limits and simplified analytical procedure.

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