Arsenic speciation in freshwater fish: challenges and research needs

Abstract

Food and water are main sources of human exposure to arsenic. It is important to determine arsenic species in food because toxicities of arsenic vary greatly with its chemical speciation. Extensive research has focused on high concentrations of arsenic species in marine organisms. The concentrations of arsenic species in freshwater fish are much lower, and their determination presents analytical challenges. We summarize in this review the current state of knowledge on arsenic speciation in freshwater fish and discuss challenges and research needs. Fish samples are typically homogenized, and arsenic species extracted using water/methanol with the assistance of sonication and enzyme treatment. Arsenic species in the extracts are commonly separated using high performance liquid chromatography (HPLC) and detected using inductively coupled plasma mass spectrometry (ICPMS). Electrospray ionization tandem mass spectrometry (ESI MS/MS), used in combination with HPLC and ICPMS, provides complementary information for the identification and characterization of arsenic species. The methods and perspectives discussed in this review, covering sample preparation, chromatography separation, and mass spectrometry detection, are directed to arsenic speciation in freshwater fish and also applicable to studies of other food items. Despite progresses made in arsenic speciation analysis, a large fraction of total arsenic in freshwater fish remains unidentified. It is challenging to identify and quantify arsenic species present in complex sample matrices at very low concentrations. Further research is needed to improve the extraction efficiency, chromatographic resolution, detection sensitivity, and characterization capability.

Development of a Fast Method Using Inductively Coupled Plasma Mass Spectrometry Coupled with High-Performance Liquid Chromatography and Exploration of the Reduction Mechanism of Cr(VI) in Foods

“…Although various methods exist for detecting Cr(VI), HPLC-ICP-MS is the most powerful. HPLC-ICP-MS has been used for the speciation analysis of elements, including Cr, arsenic, mercury, and selenium in water, soil, seafood, and tobacco due to its advantages of continuous operation, high selectivity, wide linear range, and low detection limit [24,25]. For example, Mihai et al performed speciation analysis using anion-exchange HPLC-ICP-MS and detected Cr(VI) within 9 min [26].…”