食用玫瑰花中18种有机磷农药残留量的气相色谱测定

Determination of 18 Oganophosphorus Pesticide Residues in Edible Rose by Gas Chromatography

利用气相色谱仪,建立了食用玫瑰花中18种有机磷农药残留量的测定方法。样品中农药残留2次用乙腈提取;弗罗里硅土层析柱净化中依次用30mL三氯甲烷-乙酸乙酯(9∶1,V/V)、30mL乙酸乙酯-甲醇(1∶1,V/V)作为洗脱剂。样液浓缩后注入气相色谱仪中,用双毛细管柱(DB-1、DB-17)分离、双火焰光度检测器(FPD1、FPD2)测定。制备得到的样液清亮透明,测定结果18种有机磷农药3个添加水平的平均回收率为67.23%～108.6%,相对标准偏差2.22%～14.26%。方法检出限为0.006～0.020mg·kg-1。建立的方法具有测定有机磷农药种类多、净化效果好、准确度和精密度高等优点。

The method for determination of 18 organophosphorus pesticide residues in edible rose was developed. A 25 g sample was extracted by 50 mL acetonitrile and 10 mL distilled water with a homogenizer. The extract was filtrated to a 100 mL measuring cylinder with a cap in which 10 g NaCl was added. After the mixture was shaken for 1 min and stabilized for 15 min, a 10 mL aliquot of upper phase was taken to a beaker. While a 12 mL aliquot of lower water phase was taken to a test tube with a cap, then, 12 mL acetonitrile was added into the same test tube. After extracted for 2 min with a vortex mixer and stabilized for 15 min, a 6 mL aliquot of upper phase was transferred to the same beaker. The combined acetonitrile was blown away by nitrogen gas at 80 ℃. The sample was reconstituted in 5 mL chloroform and purified using florisil column which was eluted with 30 mL chloroform-ethyl acetate （9：1, V/V） and 30 mL ethyl acetate-methanol （1：1, V/V）. The eluate was evaporated to dryness in a rotary evaporator under vacuum below 50 ℃, and the residues were reconstituted in 5 mL acetone for analysis. 18 organophosphorus pesticide residues in edible rose were separated from each other through dual capillary columns （DB-1 and DB-17） and determined with dual flame photometric detectors （FPD 1 and FPD2）. Under above conditions, the average recoveries of 18 oganophophorus pesticides at spiked levels of 0.05～0.5 mg·kg^-1 ranged from 67.23% to 108.6%, and the relative standard deviations （RSDs） were 2.22%～14.26%. The minimum detection limits were 0.006～0.020 mg·kg^-1. This method has the merits of good purifying effect, high accuracy and precision.