气相色谱法测定水产品中三氯杀螨醇残留量

Determination of Dicofol Residue in Aquatic Products by Gas Chromatography

为拓展食品中农药残留监控范围,本文建立了水产品中三氯杀螨醇的气相色谱测定方法。试验基质为鳗鲡、罗非鱼、对虾、玻纹巴菲蛤,取其可食用组织的均匀试样1g,用正己烷超声萃取,用浓硫酸和弗罗里硅土净化,二氯甲烷/正己烷混合液淋洗层析柱。洗脱液收集和旋转蒸发浓缩后,用气相色谱法测定其中的三氯杀螨醇,外标法定量。测定仪器为HP6890N型气相色谱仪,配HP7683B型自动进样器、HP-5型毛细管气相色谱柱(30m×0.32mm×0.25μm)和63Ni微电子捕获检测器。三氯杀螨醇浓度线性范围是0.0025～0.4μg.mL-(1r=0.9998,P<0.001),方法定量检测下限为0.01μg.g-1。用未检出三氯杀螨醇的鳗鲡等4种试样,添加3个水平的三氯杀螨醇,分别为0.01、0.10、0.50μg.g-1,每种试样每个添加量测定6份。结果显示,加标回收率在71%～111%范围内,批内变异系数为3.2%～8.5%(n=6),批间变异系数为2.5%～7.1%(n=4)。定量限点加标试样的回收率为73%～94%,批内变异系数为5.9%～7.7%,峰高信噪比>10。本方法试样用量少,前处理简便,可操作性强,适合测定水产品可食部分的三氯杀螨醇残留量。

A method for determining dicofol in aquatic products was established by using gas chromatography in order to widen pesticide monitoring in food. The test samples were edible tissues of eel, prawn, Oreochromis and Paphia undulata. One gram homogenized tissue sample was extracted ultrasonicly in n-hexane, then purified with concentrated sulfuric acid, dehydrated and chromatographed through a complex column of dry sodium sulfate and Florisil adsorbent. Mixed solution of dichloromethane/n-hexane pass the column, and then condensed by evaporation.Finally, the dicofol in the solution was determined by gas chromatography and external standard method. The test system composes of a HP 6890 N capillary gas chromatograph-meter, a HP 7683 B auto-injector, a HP-5 capillary column（ 30 m ×0.32 mm ×0.25μm ）, and a 6Ni micro electric capture detector. The linear range of dicofol concentration were from 0.002 5μg·mL-1 to 0.4 μg·mL-1 （r=-0.999 8, P〈0.001 ）, and the detection limit of dicofol was 0.01μg·mL-1.In the validating test, dicofol was respectively added into edible tissues of four kinds of aquatic products at three levels, 0.01, 0.10 and 0.50μg·mL-1. The results for the whole process showed recoveries from 71% to 111%, variation coefficients from 3.2% to 8.5% in each batch （n=6）and from 2.5% to 7.1% among batches （n=4）. At the level of 0.01 μg·mL-1, the recoveries ranged from 73% to 94 %, the variation coefficients ranged from 5.9% to 7.7% in each batch （n=6）, the ratio of signal to noise was greater than 10. This method was simple in preparation, and easy in operation. It needs only little tissue sample, and suits for detecting dicofol in edible tissue of aquatic products.