VOLTAMMETRIC METHOD OF SILVER DETECTION IN AQUEOUS MEDIA Russian patent published in 2008 - IPC G01N27/48 

FIELD: measuring instruments.

SUBSTANCE: silver detection method consists in electrochemical depositing of reduction products of silver onto a preliminary prepared solid working electrode of an inert material (e.g., carbon-glass-ceramics) from a solution, which contains an analyzed substance being dissolved in a base electrolyte, followed by electrochemical dissolving of previously deposited reduction products of silver and recording a voltammetric curve. The silver content is determined by an anode peak value of the electrochemical dissolving of the reduction products of silver. Sulphuric acid is used as the base electrolyte, wherein the analysed substance is preliminary dissolved, and has a concentration is not less than 0.01 mol/dm³. Copper ions are added thereto so as to obtain a total concentration of the cooper ions in the analysed solution not less than 3·10^-6 mol/dm³. The electrochemical depositing of the reduction products of silver is carried out at a negative potential of the solid working electrode set to a range from - 250 mV to -300 mV (with respect to a silver chloride reference electrode). The deposited reduction products of silver are electrochemically dissolved at a rate of change in potential on the working electrode not exceeding 500 mV/sec and a voltammetric curve is recoreded. The analytical signal of finding silver is an anode peak height of the electrochemical dissolving of silver on the voltammetric curve in the region of potentials from +300 mV to +500 mV. The microconcentration of silver is measured thereupon.

EFFECT: invention allows to measure microconcentrations of silver different objets to a high precision, and the ions of other elements, being present in the analysed solution, do not hinder the determination of microconcentrations of silver ions, thus allowing to raise the silver detection limit.