Analytical methods for the determination of total arsenic (TAs) and arsenic species (arsenite-As(III), arsenate-As(V), monomethylarsenic acid-MMA, dimethylarsenic acid-DMA and arsenobetaine-AsB) in freshwater fish samples were developed. Inductively coupled plasma mass spectrometry with dynamic reaction cell (ICP-DRC-MS) and high-performance liquid chromatography hyphenated to ICP-DRC-MS were used for TAs and arsenic species determination, respectively. The DRC with oxygen as a reaction gas was used. Sample preparation, digestion, and extraction were optimized. Microwave assisted digestion and extraction provided good recovery and extraction efficiency. Arsenic species were fully separated in 8 min using 10 mmol L-1 of ammonium dihydrogen phosphate and 10 mmol L-1 of ammonium nitrate. Overlapping of AsB and As(III) of arsenic species in the presence of a high concentration of AsB and trace amounts of As(III) were studied. Detailed validation of analytical procedures proved the reliability of analytical measurements. Both procedures were characterized by short-term and long-term precision: 2.2% (TAs) up to 4.2% (AsB), and 3.6% (TAs) up to 7.2% (DMA), respectively. Limits of detection (LD) were in the range from 0.056 µg L-1 for TAs to 0.15 µg L-1 for As(V). Obtained recoveries were in the range of 85%⁻116%. Developed methods were applied to freshwater fish samples analysis.
Keywords: HPLC/ICP-DRC-MS; ICP-DRC-MS; arsenic; freshwater fish; speciation.