Evaluation of different sample pre-treatment and extraction procedures for mercury speciation in fish samples
Evaluation of different sample pre-treatment and extraction procedures for mercury speciation in fish samples
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DOI：
10.1039/b207334j
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发表时间：
2002-12
影响因子：
3.4
通讯作者：
A. Ortiz;Yolanda Madrid Albarrán;C. C. Rica-C.
中科院分区：
文献类型：
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作者：
A. Ortiz;Yolanda Madrid Albarrán;C. C. Rica-C.
调查描述了选择最合适的干燥和提取程序的汞物种在鱼样品。选择的标准是对原始物种信息的良好恢复和保存。评估了三种不同的干燥技术：烘箱干燥，微波炉干燥和冷冻干燥。烘箱干燥效果最好，但微波干燥或冷冻干燥会造成汞损失。研究了四种提取方法：盐酸浸出法、四甲基氢氧化铵（TMAH）和KOH碱-甲醇萃取法和十二烷基硫酸钠（SDS）萃取法。通过比较微波消解后样品中汞的总含量与不同提取方法的提取量，确定了提取效率。采用流动注射-冷蒸汽原子荧光光谱法（FI-CV-AFS）测定汞含量。定量汞提取只能通过HCl浸出（97%）实现。采用毛细管气相色谱-原子荧光光谱法研究提取后的物种完整性。当TMAH用作萃取剂时，会人工形成二甲基汞。最后将盐酸浸出-气相色谱- afs法应用于金枪鱼和旗鱼样品中甲基汞的测定，测定结果在0.78 ~ 1.93 mg kg−1之间。单甲基汞（MMHg）的检出限为1.2 pg。
Investigations are described to select the most suitable drying and extraction procedures for mercury speciation in fish samples. The criteria for selection were good recovery and preservation of the original species information. Three different drying techniques were evaluated: oven-dried, microwave oven-dried and freeze-dried. Best results were obtained when oven-dried, but microwave dried or freeze-dried showed mercury losses. The four extraction methods investigated were: HCl leaching, alkaline–methanol extraction with tetramethylammonium hydroxide (TMAH) and with KOH, and sodium dodecyl sulfate (SDS) extraction. The extraction efficiency was determined by comparing the total amount of mercury in the samples after microwave digestion with the amount extracted by the different methods described. Mercury measurements were carried out by flow injection-cold vapour-atomic fluorescence spectrometry (FI-CV-AFS). Quantitative mercury extraction was only achieved with HCl leaching (97%). Species integrity after extraction was evaluated by investigating the extracts with capillary gas chromatography-atomic fluorescence spectrometry. Artificial formation of dimethylmercury occurs when TMAH is used as extractant. HCl leaching-GC-AFS was finally applied to methylmercury determination in tuna fish and swordfish samples, and gave results in the range 0.78–1.93 mg kg−1. The detection limit for monomethylmercury (MMHg) was found to be 1.2 pg.