Speciation analysis of six arsenic species in marketed shellfish: Extraction optimization and health risk assessment

- Microwave exhibited higher efficiency in shellfish As extraction than sonication.
- Diluted nitric acid is more efficient in extraction of inorganic As.
- Both AsB and iAs concentrations were increased with tAs concentration increasing.
- AsB% was negatively correlated with tAs due to biotransformation threshold.

A comparative study between microwave assisted and sonication methods was carried out to extract arsenic (As) species in shellfish samples using different extractants. Six As species including arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB) and arsenocholine (AsC) were simultaneously separated and determined by the HPLC-ICP-MS method. The microwave assisted method exhibited higher efficiency than sonication, especially using diluted HNO3 as extractant. By compromising extraction efficiency, pretreatment time and stability of As species, the microwave assisted method using 1% HNO3 at 100 °C for 1.5 h was selected to extract As from real samples. The proposed method has been applied to extract and determine As species in shellfish samples. The result of correlation analysis indicated that the proportion of AsB in the shellfish samples was decreased with total As concentration increasing due to the biotransformation threshold from inorganic As to AsB.