气相色谱-负离子化学电离质谱法测定水产品中残留的硫丹及其代谢物

建立了水产品中α-硫丹、β-硫丹及硫丹硫酸酯残留量的分析方法。样品经丙酮-正己烷混合溶剂提取、转溶至乙腈中、冷冻去除油脂、活性炭和中性氧化铝固相萃取小柱(SPE)串联净化处理后,以选择离子方式进行气相色谱-负离子化学电离质谱分析，采用外标法定量。硫丹和硫丹硫酸酯的选择离子分别为m/z 406,408,404,372和m/z 386,388,384,422。每种化合物的最低定量检测限为0.5 μg/kg,回收率为83%～105%,相对标准偏差低于13%。该方法简单、快速、准确,能满足水产品中硫丹残留的检测需要。

Determination of Endosulfans and Its Metabolite in Fishery Foods Using Gas Chromatography-Mass Spectrometry with Negative Ion Chemical Ionization

Endosulfan is one of the organochliorine pesticides and contains two stereoisomers, alpha-endosulfan and beta-endosulfan. Endosulfan sulfate is the oxide of endosulfan with toxicity comparable to endosulfan. The method was developed for the analysis of alpha-endosulfan, beta-endosulfan and endosulfan sulfate in fishery foods. Since the maximal residue level is set at about 4 - 6 microg/kg in many countries, the acceptable method must be sensitive and accurate. The conditions were systematically optimized and external standard method was used for the quantification. The sample was extracted by acetone and hexane (1 : 1, v/v), removed fat by transfering to acetonitrile and cold, and cleaned up with an Envi-Carb column and an LC-Alumina-N column, and analyzed by gas chromatography-mass spectrometry negative ion chemical ionization with selective ion mode. The selective ions of endosulfans and endosulfan sulfate were m/z 406, 408, 404, 372 and m/z 386, 388, 384, 422, respectively. The lowest quantitative limited level of every compound was 0. 5 microg/kg, and the recoveries were 83% - 105%, and the relative standard deviations were less than 13%. The method is efficient, accurate and sensitive to meet the requirements for determining endosulfans in fishery foods.