Simultaneous pressurized enzymatic hydrolysis extraction and clean up for arsenic speciation in seafood samples before high performance liquid chromatography-inductively coupled plasma-mass spectrometry determination

The feasibility of pressurized conditions to assist enzymatic hydrolysis of seafood tissues for arsenic speciation was novelty studied A simultaneous in situ (in cell) clean-up procedure was also optimized which speeds up the whole sample treatment Arsenic species (As(III) MMA DMA As(V) AsB and AsC) were released from dried seafood tissues using pepsin as a protease and the arsenic species were separated/quantified by anion exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) Variables inherent to the enzymatic activity (pH temperature and ionic strength) the amount of enzyme (pepsin) and factors affecting pressurization (pressure static time number of cycles and amount of dispersing agent C-18) were fully evaluated Pressurized assisted enzymatic hydrolysis (PAEH) with pepsin can be finished after few minutes (two cycles of 2 min each one plus 3 min to reach the hydrolysis temperature of 50 C) A total sample solubilisation is not achieved after the procedure however it is efficient enough for breaking down certain bonds of bio-molecules and for releasing arsenic species The developed method has been found to be precise (RSDs lower than 6% for As(III) DMA and As(V) and 3% for AsB) and sensitive (LOQs of 18 1 362 357 28 6 20 6 and 22 5 ng/g for As(III) MMA DMA As(V) AsB and AsC respectively) The optimized methodology was successfully applied to different certified reference materials (DORM-2 and BCR 627) which offer certified AsB and DMA contents and also to different seafood products (mollusks white fishes and cold water fishes) (C) 2010 Elsevier B V All rights reserved