EXPERIENCES WITH THE ANALYTICAL PROCEDURES FOR THE DETERMINATION OF METHYLMERCURY IN ENVIRONMENTAL-SAMPLES

The analytical method using ethylation, gas chromatography-cold vapor atomic fluorescence spectroscopy (GC-CV AFS), combined with different pretreatment procedures, has been used for the determination of methyl mercury (MeHg) in various aqueous and solid environmental samples. Dif ferent types of samples with varying matrices and MeHg concentration l evels require different pretreatment procedures in order to isolate/se parate MeHg from the sample matrix, and to overcome interferences in t he ethylation reaction process. Limitations of different pretreatment procedures (solvent extraction into methylene chloride, distillation u nder nitrogen dow and alkaline digestion) are discussed and recommenda tions are given. The influence of the quality of the ethylating reagen t on the analytical results is also examined.