High-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry for determining arsenic species and applications in seafood safety monitoring

Arsenic is a widely studied toxic element that exists in various species with different oxidation states and forms in the environment and biological systems. The different physicochemical properties, environmental behaviors, and toxicities of these arsenic species make speciation analysis essential for environmental monitoring and human health risk assessment. In this study, we demonstrated the determination and monitoring of six arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenocholine (AsC), and arsenobetaine (AsB) in seafood using high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). We optimized the chromatographic condition and sample preparation for the separation and extraction of arsenic species, and the method was validated with accuracy and reproducibility using certified reference materials and actual samples. Baseline separation of the arsenic species was achieved within 12 min, and oven heat extraction was selected for sample preparation. The method showed excellent linearity for arsenic species from 0.1 to 100 μg L⁻¹, with recoveries ranging from 92% to 123%, intra-day precision of 0.9–5.0%, and inter-day precision of 1.1–19.4%. The method was further used to determine the arsenic species in 109 mollusks, 195 crustaceans, and 195 marine fish samples from Guangdong, China. Distinctive patterns of arsenic species distribution were observed among different seafood categories. AsB was consistently the predominant species across all samples, with a detection frequency higher than 97.9% and contributed to more than 90% of total arsenic, other arsenic species showed marked variations in their occurrence and concentrations.