Abstract: The distribution characteristics of total arsenic and arsenic species in four sea crabs (Scylla serrata, Portunus trituberculatus, Charybdis japonica and Ovalipes punctatus) and their different tissues (chest muscle, clamp meat, hepatopancreas and female gonad and gill) were studied by inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Samples were acidified, digested in microwave and tested by ICP-MS for total arsenic. After samples were extracted with dilute nitric acid solution and degreased with n-hexane, an HPLC-ICP-MS method using a Dionex IonPac AS19 guard column (50 mm × 4 mm) and an AS19 anion exchange analytical column (250 mm × 4 mm, 10 μm) with 50 mmol/L carbon acid ammonium (pH 9.5) in isocratic elution as the mobile phase was used to analyze 5 arsenic species (AsB, MMA, DMA, As (III), and As (V)). The optimized method showed a good linear relationship over the concentration range of 0–300 μg/L (r2 > 0.998). The limits of detection (LOD) and the limits of quantity (LOQ) were 0.008–0.014 mg/kg and 0.025–0.055 mg/kg, respectively. The recovery rates at spiked levels of 0.4–2.0 mg/kg were 70.0%–105.0% with relative standard deviations (RSDs) smaller than 5%. Total arsenic contents in 158 sea crab samples were 0.37–35.81 mg/kg, and the analytical data of arsenic species in whole crabs and crab tissues showed that AsB, with low toxicity, was the main form of arsenic in sea crab, accounting for 60.9%–99.4% of the total arsenic. Additionally, average inorganic arsenic content was only 0–0.12 mg/kg in all samples, below the national standard limit. The contents of total arsenic and AsB in different sea crab species were in the ascending order of O. punctatus < S. serrata < P. trituberculatus < C. japonica, and those in different crab tissues were in the descending order of female gonad > hepatopancreas > chest muscle > clamp meat > gill. This research suggested that sea crabs have strong As accumulation ability, mainly in gonad and hepatopancreas.

Key words: sea crab, arsenic, distribution characteristics, inductively coupled plasma mass spectrometry