Speciation of cationic arsenic species in seafood by coupling liquid chromatography with hydride generation atomic fluorescence detection

Abstract

A method was developed for determining arsenobetaine (AB), arsenocholine (AC), trimethylarsine oxide (TMAO) and tetramethylarsonium ion (TMA⁺) in seafood products. The arsenic species were extracted from the matrix by methanol–water and the extracts were quantified by high-performance liquid chromatography coupled with thermo-oxidation hydride generation atomic fluorescence spectrometry (HPLC–thermo-oxidation–HG-AFS). The variables affecting each stage of the methodology were optimized. The analytical features of the method (recovery, precision, limit of detection and linearity range) were calculated for each arsenical species. The lowest limit of detection was obtained for TMAO (0.0009 µg g⁻¹, dry mass), whereas AC was the arsenic species with the highest LOD (0.0063 µg g⁻¹, dry mass). The precision of the method varied between 0.7% for AB and 8.4% for TMA⁺. The recovery percentage was greater than 97% for all species. The proposed procedure was applied to reference materials: DORM-2 (Dogfish muscle, National Research Council of Canada), NFA-Shrimp and NFA-Plaice (National Food Agency of Denmark). The results were compared with the values obtained by other authors.