Determination of the total mercury in a filtrate of wash-off samples from contaminated surfaces
Quantitative determination of the total mercury content in filtrates of wash-off samples from the surfaces of walls, floors, equipment, and other facilities of m anufacturing areas is an effective method for the occupational safety monitoring.
An important application of the analysis results is the evaluation of the demercurization efficiency at factories that use mercury or mercury compounds. According to the regulations, a routine demercurization should be carried out regularly during the period of mercury use.
Laboratory survey of the demercurization efficiency is carried out by a comparative analysis of the mercury content in the air and rinse samples from contaminated surfaces before and after demercurization.
Method of determination of the total mercury concentration in filtrates of wash-off samples is based on the reduction of mercury cations to the atomic state using a stannous chloride reducing solution in the reaction vessel of an RP-91 attachment (the "cold vapor" technique) and then measuring the mercury atomic concentration in the analytical cell of a mercury analyzer RA-915M/RA-915+ with the Zeeman background correction.
The mercury content in a sample is determined by the value of the integrated analytical signal using a preset calibration.
The total time needed for determination of mercury is not longer than 2 minutes.
RA-915+/915M is compliant with US EPA 1631, EN M83 methods.
The measurement range of the mercury concentration in rinse samples is 0.2–10,000 μ g/l (for a sample volume of 5 ml).