ELECTROCHEMICAL MODE OF DETERMINATION OF SELENIUM AND ARSENIC IN NATURAL OBJECTS Russian patent published in 2007 - IPC G01N27/48 

FIELD: the invention refers to analytical chemistry.

SUBSTANCE: for conducting impressive background monitoring of water ecosystems, identification of natural and antropogenic sources of ingressing in them of arsenic it is necessary to determinate small concentrations in an interval from 0,1 to 3 maximum permissible concentration. The invention proposes an electrochemical mode of determination of selenium and arsenic in natural objects in which for recovery of all forms of elements including hybrids it is necessary to use a solution consisting out of water, 1% of sodium hydroxide and 3% of sodium borohydride. For extraction of selenium and of arsenic microadditions of gold comparable on content with selenium and arsenic are added into the solution. The analyst is accumulated on the surface of the graphite electrode at constant potential 0,0 V during 90 seconds using gold as a collector of hydrogen solenide and arsine.

EFFECT: after the stage of accumulation an analytical signal in the shape of a pick of the cathode current is registered at potential from -0,5 to -0,6 V of selenium and from -0,8 to 0,9 V of arsenic in the mode of differential-impulse current-voltage, linear dependent from the concentration of selenium and arsenic in the volume of the analytical probe.

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