This document specifies a method for the determination of alkylmercury compounds in filtered water 
samples by gas chromatography-mass spectrometry after phenylation and solvent extraction.
This method is applicable to determination of individual methylmercury (MeHg) and 
ethylmercury (EtHg) compounds in surface water and waste water.
The method can be applied to samples containing 0,2 μg/l to 10 μg/l of each compound as mercury 
mass. Depending on the matrix, the method may also be applicable to higher concentrations after 
suitable dilution of the sample or reduction in sample size.st edition 2020-11 Water quality — Determination of alkylmercury compounds in water — Method using gas chromatography- mass spectrometry (GC-MS) after phenylation and solvent extraction Qualité de l'eau — Détermination des composés alkyl mercure dans l'eau — Méthode par chromatographie gazeuse et spectrométrie de masse (CG-SM) après phénylation et extraction par solvant Reference number ISO 21863:2020(E) ？ ISO 2020 ISO 21