![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
R9 Laboratory SOP 415
Preparation of Water Samples for Mercury Analysis
Summary
This SOP describes the sample and standard preparation steps for mercury analysis. The analytical procedures for mercury are contained in Region 9 Laboratory SOP 515. The samples can be analyzed using the CETAC M6000A Automated Mercury Analyzer (for drinking and lowlevel waters) and the Leeman PS200 Automated Mercury Analyzer (for all other sample matrices). This method is applicable for the preparation of drinking, ground, surface, sea and brackish water, domestic and industrial wastes for total mercury (organic + inorganic) by EPA Method 245.1.
An aliquot of a water sample is transferred to a BOD bottle or equivalent closed-system container. The sample is digested with nitric acid, sulfuric acid, and a dilute potassium permanganate-potassium persulfate solution for two hours at 95°C. The digestion oxidizes all forms of mercury to Hg(II). The Hg(II) in the digested water sample is reduced with stannous chloride to elemental mercury which is sparged from the sample and detected by atomic absorption. The measurement step is performed using an automated mercury analyzer and is detailed in Region 9 Laboratory SOP 515.