Abstract
A procedure for determining both tetraalkyllead (TAL) and ionic alkyllead (IAL) compounds in soft mussel tissues is described, including a critical evaluation of the effects of digestion, extraction and derivatization procedures on the recovery of particular alkyllead compounds. The optimized procedure which was developed included digestion of mussel tissue with tetramethylammonium hydroxide at room temperature. For TAL determination the digest was extracted with hexane. For IAL extraction, sodium diethyldithiocarbamate (0.25 M) and sodium chloride (5g) were added to the aqueous phase left after TAL extraction followed by a double extraction with separate hexane aliquots. IAL compounds were determined following propylation using an appropriate Grignard reagent followed by gas chromatography-atomic absorption spectrometric (GC-AAS) detection. If TAL and IAL compounds were determined together, the same extraction as for IAL compounds was performed without a prior TAL hexane extraction. For differential pulse anodic stripping voltammetric (DPSAV) detection of IAL compounds the separated hexane layer was re-extracted twice with acidic solution in which IAL was measured. The GC-AAS and DPSAV determinations of IAL in mussel tissue and various natural water samples, were compared. The comparison showed a good agreement for trialkylleads but some divergence for dialkylleads.