Inter-laboratory validation of EPA method 3200 for mercury speciation analysis using prepared soil reference materials

Determinations of the concentration of individual mercury species from environmental samples have increased significantly over the past decade. The techniques used for the determination of mercury species in soils or sediments generally involve a series of analytical steps (extraction, separation, detection) that may all be prone to systematic errors. An inter-laboratory validation study of the EPA draft method 3200 was conducted under the auspices of the United States Environmental Protection Agency on two specifically prepared soil matrices. The study was performed successfully by a limited number of participating laboratories. Evaluation of the data demonstrates that the method is more highly efficient for extracting the highly toxic methylmercury than inorganic mercury. The proposed method does not induce transformation of methylmercury to inorganic mercury. Copyright (c) 2005 John Wiley & Sons, Ltd.