Arsenic speciation in seafood by LC-ICP-MS/MS: method development and influence of culinary treatment

Abstract

Arsenic speciation in seafood after several culinary treatments was performed and AsB, As(III), DMA, MMA and As(V) species were determined by liquid chromatography hyphenated to triple-quadrupole inductively coupled plasma mass spectrometry (LC-ICP-MS/MS) using O₂ as the reaction gas for the conversion of ⁷⁵As to ⁷⁵As¹⁶O. The influence of culinary treatments (boiling, frying and sautéing) with or without the addition of spices (salt, lemon juice and garlic) on the As species in blacktip shark and Asian tiger shrimp was investigated. Arsenic species were extracted by using a 30 mmol L⁻¹ HNO₃ solution. Ammonium phosphate (10 mmol L⁻¹) was used as the mobile phase. The influence of pH and the addition of 1% (v/v) methanol were investigated. Oil, water, butter and the spices used during cooking were analysed to perform a close mass balance of the total As. The speciation method was also employed for a certified reference material (CRM, DORM-3), and the accuracy was evaluated by statistical comparison between the certified value and the total As concentration determined by ICP-MS after acid digestion and also by a comparison of the sum of As species with the total As. It was demonstrated that the culinary treatments practically did not influence the stability of As species in uncooked seafood. On the other hand, significant analyte losses (from 15 up to 45%) were observed for boiled seafood. The speciation analysis method presented accuracy and robustness for both raw seafood and seafood after the culinary treatments. The limits of quantification were 4, 21, 4, 9 and 18 ng g⁻¹ for AsB, As(III), DMA, MMA and As(V), respectively. This study allowed the determination of As species in seafood after culinary treatments, thus offering additional information about the behaviour of species during cooking.