Single laboratory validation of a method for arsenic speciation analysis in seafood and seaweed is presented. The method is based on stepwise extraction of water-soluble and non-polar arsenic with hot water and a mixture of dichloromethane and methanol, respectively. While the water-soluble arsenicals were speciated by anion and cation exchange liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS), the non-polar arsenicals were collectively determined by ICP-MS after digestion in acid. The performance characteristics and broad application of the method were evaluated by analyzing eight commercial samples (cod, haddock, mackerel, crab, shrimp, geoduck clam, oyster, and kombu) and four reference materials (fish protein (DORM-4), lobster hepatopancreas (TORT-3), mussel tissue (SRM 2976), and hijiki seaweed (CRM 7405-a)) representing finfish, crustaceans, molluscs, and seaweed. Matrices spiked at three levels in duplicates were also analyzed. The stepwise extraction provided 76–106% extraction of the total arsenic from the test materials. The method demonstrated satisfactory repeatability for analysis of replicate extracts prepared over several days. The accuracy of the method was evaluated by analyzing reference materials certified for both total arsenic and a few arsenicals; the experimental results were 90–105% of the certified values. Comparison between the total water-soluble arsenic and the sum of the concentrations of the chromatographed species gave 80–92% mass balance. While spike recoveries of most arsenicals were in the acceptance range set by CODEX, a few species spiked into cod, haddock, and shrimp were poorly recovered due to transformation to other forms. After thorough investigations, strategies were devised to improve the recoveries of these species by averting their transformations. Limits of quantification (LOQ) for the extraction and quantification of 16 arsenicals using the current method were in the range 6–16 ng g⁻¹ arsenic.

中文翻译：

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海鲜和海藻中砷的形态分析：第二部分-方法的单一实验室验证

提出了在海鲜和海藻中进行砷形态分析的方法的单实验室验证。该方法基于分别用热水和二氯甲烷和甲醇的混合物逐步提取水溶性和非极性砷的方法。水溶性砷化物是通过阴离子和阳离子交换液相色谱电感耦合等离子体质谱法（LC-ICP-MS）指定的，而非极性砷化物是在酸中消化后通过ICP-MS共同测定的。通过分析八种商业样品（鳕鱼，黑线鳕，鲭鱼，蟹，虾，象拔蚌，牡蛎和海带）和四种参考物质（鱼蛋白（DORM-4），龙虾肝胰腺）评估了该方法的性能特点和广泛应用（TORT-3），贻贝纸巾（SRM 2976），和hijiki海藻（CRM 7405-a）），代表有鳍鱼，甲壳类，软体动物和海藻。还对一式三份加标到三个水平的基质进行了分析。逐步萃取可从测试材料中萃取出总砷的76–106％。该方法显示了令人满意的可重复性，可用于分析几天内制备的重复提取物。通过分析经认证的总砷和少量砷的参考物质，评估了该方法的准确性。实验结果为认证值的90–105％。将总水溶性砷与色谱物质的浓度总和进行比较，可得出80-92％的质量平衡。尽管大多数砷的加标回收率处于CODEX设定的可接受范围内，但少数物种加标到了鳕鱼，黑线鳕，和虾由于转化为其他形式而回收率很低。经过深入的调查，制定了一些策略，通过避免其转化来提高这些物种的回收率。使用当前方法提取和定量16种砷的定量限（LOQ）在6–16 ng g范围内^-1砷。