超高效合相色谱法快速测定婴幼儿辅食果泥中甲氰菊酯对映体的残留量

Rapid Determination of Residues of Fenpropathrin Enantiomers in Fruit Puree of Infant Dietary Supplement by Ultra-High Performance Convergence Chromatography

在5 g婴幼儿辅食果泥样品中加入乙酸乙酯20 mL和氯化钠3.0 g,涡旋2 min,离心5 min,用20 mL乙酸乙酯重复提取一次,合并两次上清液,于40℃减压浓缩至近干,加入5 mL甲醇溶解残渣。所得溶液过活化好的C18固相萃取柱,收集全部流出液,于40℃氮吹至近干,加入1 mL正庚烷,涡旋1 min溶解残渣,过0.22μm有机相滤膜,滤液用超高效合相色谱法(UPC2)分析。以Acquity Trefoil AMY1色谱柱为固定相,以不同体积比的含0.5%(体积分数)氨水的甲醇溶液和超临界二氧化碳的混合溶液为流动相进行梯度洗脱,在230 nm波长下检测(-)-甲氰菊酯和(+)-甲氰菊酯,外标法定量。结果显示,甲氰菊酯对映体的质量浓度在1.0~20.0 mg·L^(-1)内和对应的峰面积呈线性关系,测定下限(10S/N)均为0.2 mg·kg^(-1)。对阴性果泥样品进行3个浓度水平的加标回收试验,两种目标物的回收率为81.4%~106%,测定值的相对标准偏差(n=6)为4.1%~7.2%。方法用于20份果泥样品的分析,仅在1份梨泥样品中检出(-)-甲氰菊酯(0.25 mg·kg^(-1))和(+)-甲氰菊酯(0.22 mg·kg^(-1))。

Ethyl acetate(20mL)and 3.0g of sodium chloride were added into 5g of fruit puree of infant dietary supplement sample.The mixture was vortexed for 1min,and centrifuged for 5min.The extraction was repeated once with 20mL of ethyl acetate.The two supernatants were combined and evaporated to near dryness under vacuum at 40℃.The residue was dissolved in 5 mL of methanol.The solution was passed through the activated C18solid phase extraction column,and the entire effluent was collected,and dried to near dryness by nitrogen at 40℃.Then 1mL of heptane was added,and vortex process was made for 1min to dissolve the residue.The solution obtained was filtered through a 0.22μm organic phase filter membrane,and the filtrate was analyzed by UPC2.Acquity Trefoil AMY1column was used as the stationary phase.Mixed solutions composed of methanol solution containing 0.5%(φ)ammonia and supercritical carbon dioxide at different volume ratios were used as the mobile phase for gradient elution.(-)-Fenpropathrin and(+)-fenpropathrin were determined by external standard method at detection wavelength of 230nm.It was shown that linear relationships between values of the mass concentration and peak area of the fenpropathrin enantiomers were kept in the range of 1.0-20.0mg·L^(-1),with lower limits of determination(10S/N)of 0.2mg·kg^(-1).The spiked recovery test was made at three concentration levels on the negative fruit puree samples,giving recoveries of the 2targets in the range of 81.4%-106%,and RSDs(n=6)of the determined values in the range of of 4.1%-7.2%.The proposed method was used for the analysis of 20fruit puree samples,and(-)-fenpropathrin(0.25mg·kg^(-1))and(+)-fenpropathrin(0.22mg·kg^(-1))were detected in one pear puree sample.