Determination of Methylmercury in Selected Marine Organisms by Gas Chromatography

This reference method describes a gas chromatographic procedure for determining methylmercury in selected marine biological organisms. It covers the analytical process from sampling and sample preparation through dry-weight determination, extraction, clean-up, gas chromatographic analysis, calculation of results, precision and accuracy assessment, quality control, and reporting. The method uses acid liberation of methylmercury from homogenised biological material, extraction into benzene, separation from interfering substances using cysteine, and subsequent gas chromatographic measurement. It specifies required reagents, apparatus, preparation of standards, operating conditions, calibration procedures, quality control checks, and reporting requirements. The document also provides a test-report form for recording analytical conditions, results, precision, accuracy, and other relevant information.