ABSTRACT
Organomercury compounds belong to the most dangerous compounds in the environment. They are highly toxic and are often found concentrated at the end of the food web. A lot of attention has been paid to the development of reliable, precise and sensitive methods for the determination of methylmercury, the predominant and most dangerous organomercury compound, in biological samples. The most widely used analysis techniques are gaschromatography with electron capture detection (GC-ECD) or microwaveinduced plasma detection (GC-MIP). However, prior to injection of the sample to the GC-column, elaborate and time consuming extractions had to be done. The use of headspace sampling (1) strongly simplified the analyses procedure, since all reaction steps are taking place in the HS-vial. Moreover, column performance degradation, observed with direct injection, no longer occured since only volatile compounds are injected on the column. Recently, the HS-extraction method was improved (2). Liberation of the methylmercury from biological tissue was accomplished by the use of sulfuric acid in the presence of iodoacetic acid, to convert all released methylmercury to the more volatile iodide salt. Indeed, for aqueous solutions, the sensitivity obtained with methylmercury iodide is much better than with the chloride form. The liberated methylmercury was then determined, as before, by gas chromatography and microwave-induced plasma detection (HS-GC-MIP).
