茶叶中2,4-D残留量的检测

为了解决出口茶叶中2,4-D的残留检测的难题,研究了茶叶中2,4-D的残留检测的方法。样品采用酸性乙腈提取,用三氟化硼甲醇溶液将2,4-D衍生成2,4-D甲酯,经过液-液萃取,用弗罗里硅土柱层析净化除去干扰物质,以气相色谱电子捕获检测器测定,依据色谱峰保留时间定性,外标法峰面积定量。该方法在0.01-0.5mg/kg范围内呈线性,平均回收率为80.1%～93.0%,相对标准偏差为1.4%～4.3%.

Determination of 2,4 - D residue in tea

For effective detecting 2,4-Dichlorophenoxyacetic(2,4-D)residue in tea for export,a quick analytical method was developed.Extracted by acidic acetonitrile and using boron trifluoride methanol,the sample was derivatives into 2,4-D ester.After liquid-liquid extraction,then using Florey silica column chromatography to purify and remove interfering substances,it was determined by Gas Chromatography with Electron Capture Detector(GC-ECD).Qualitative analysis is based on the retention time of the peak Chromatogram,quantitative analysis is based on peak area of external standard method.The method is linear within the range between 0.01 and 0.5mg/kg,The average ratio of recovery ranges from 80.1% to 93.0%,the relative standard deviation ranges from 1.4% to 4.3%.