气相色谱-质谱法测定韭菜中2，4-D丁酯

以乙腈超声提取韭菜中2，4-D丁酯，80 ℃水浴中氮气吹至近干，以丙酮溶解，以活性炭、弗罗里硅土、氧化铝柱净化，以气相色谱-质谱选择 m/z 162、175、185、276四个碎片离子进行定性定量分析。2，4-D丁酯在0.002～1.0 μg /mL成线性（r=0.999 9），2种不同加标浓度0.01和1.0 μg /mL下 2，4-D丁酯平均回收率分别为88.2%、94.3%，相对标准偏差分别为6.93%、6.89%，样品中最低检出浓度（S/N＝3）为0.02 μg/kg。 本方法适用于韭菜等蔬菜和水果中2，4-D丁酯的测定。

Determination of 2,4-D-butyl Ester in Chinese Leek by Gas Chromatography-Mass Spectrometry

A method of determination of 2,4-D-butyl ester in Chinese Leek by GC/MS is established. 2,4-D-butyl ester in Chinese Leek was extracted with acetonitrile by ultrasonic wave. The extract was warmed with water at 80 ℃ and blowed with nitrogen gas until it got near to dryness. Then it was dissolved in acetone and cleaned-up by florisil-charcoal-alumina glass column. Retention time and specific ions were used to identify 2,4-D-butyl ester. The selective fragments were m/z 162, 175,185, 276, respectively. The calibration curve of 2,4-D-butyl ester was linear (correlatiom coefficient: 0.999 9) within the range of 0.002-1.0 μg/mL. The recoveries (spiking at 0.01 μg/mL and 1.0 μg/mL ) were 88.2%, 94.3%, respectively. The relative standard deviations (RSD) of the method was <10% for each case, and the limit of detection (LOD), defined in termes of 3 times baseline noise was 0.02 μg/kg. The method is suitable for determining 2,4-D-butyl ester in Chinese Leek and other vegetables and fruits.