Arsenic speciation in seafood samples with emphasis on minor constituents: an investigation using high-performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

Abstract

Extracts of 11 samples of shrimp, crab, fish, fish liver, shellfish and lobster digestive gland (hepatopancreas), including five certified reference materials, were investigated for their contents of arsenic compounds (arsenic speciation). The cation-exchange high-performance liquid chromatography procedure was optimized to separate six cationic arsenicals present in the samples with internal chromatographic standardization by the trimethylselenonium ion, which was detected at m/z 82 pSe), in addition to arsenic at m/z 75, by inductively coupled plasma mass spectrometry. The content of each species (as arsenic atom) relative to the total arsenic extracted from the samples were: arsenobetaine 19-98%, arsenocholine and trimethylarsine oxide O-O.6% and the tetramethylarsonium ion 0-2.2%. Additionally, an unknown arsenic species (Ul) was present at 3.1 -1 8% in the shellfish and in the lobster digestive gland, and another unknown (U2) was present at 0.2-6.4% in all samples. The contents of arsenite and arsenate were 0-1.4%, dimethylarsinate 8.2-29% while monomethylarsonate was detected only in oyster at 0.3% of the total extracted arsenic. Finding tetramethylarsonium ion and arsenocholine in a variety of samples indicates steps of a biosynthetic pathway of arsenic leading to arsenobetaine in the marine environment. The intake of inorganic arsenic via ingestion of the seafood samples that were analysed did not represent a toxicological problem to humans. The limits of detection (LOD) were in the range 10-50 ng g-' (dry mass) with the exception of arsenobetaine for which the LOD was 360 ng g-l.

Development and application of a robust speciation method for determination of six arsenic compounds present in human urine.

“…The current reported method for determination of six arsenic species in urine using an ammonium carbonate buffer resulted in acceptable performance and significant improvement over the existing methods reported in the literature (6)(7)(8)(9)(10)(11)(12)(13)(14). The method uses cationic and anionic columns in series for complete baseline separation of six arsenic species and the internal standard, in a single chromatographic run of less than 30 min.…”

“…There have been many studies involving speciation by the coupling of ion-exchange chromatography (IC) to ICP-MS (IC-ICP-MS) (6,7); however, studies reported in the literature have employed two separate columns (anionic and cationic). Using a single column to separate the six aforementioned arsenic species is difficult because AsC exists in cationic form at most pH levels, whereas the other five species can be made anionic by adjusting the pH.…”

Determination of Arsenic Species in Marine Samples by HPLC-ICP-MS

“…[1][2][3][4][5][6] In marine organism, more than 17 different inorganic and organic species have been reported. 7 In marine algae, arsenosurgars compounds (derivatives of dimethylarsinoylribosides and trimethylarsonioribosides) are most abundant. [2][3][4][5][6][7] The analytical speciation of arsenic has been achieved with the use of coupled techniques, which combine a separation process (chromatography) with suitable detection.…”

“…7 In marine algae, arsenosurgars compounds (derivatives of dimethylarsinoylribosides and trimethylarsonioribosides) are most abundant. [2][3][4][5][6][7] The analytical speciation of arsenic has been achieved with the use of coupled techniques, which combine a separation process (chromatography) with suitable detection. Hydride generation atomic absorption spectrometry (HG-AAS) has been used for arsenic speciation in which online thermal or microwave oxidation was employed for converting many organoarsenicals into hydride forming one.…”

“…Tetrabutyl ammonium hydroxide is common ion pairing agent used for separating anionic species and pentanesulfonate or hexanesulfonate 16 for separating cationic species. Kohlmeyer et al 7 have demonstrated the separation of 17 arsenic species (eight arsenic species, two arsenosugars and seven unknown species) from various seafood products using nitric acid pH Arsenic speciation analysis in marine samples was performed using high performance liquid chromatography (HPLC) with ICP-MS detection. The separation of eight arsenic species viz.…”