農產品中農藥殘留量標準分析方法之建立－－普伏松、芬殺松及加芬松之檢驗方法

ANALYTIC METHODS FOR DETERMINING THE RESIDUES OF ETHOPROP, FENTHION AND CARBOPHENOTHION IN CROPS

行政院衛生署于77年4月公告增訂殘留農藥安全容許量標準，農藥種類已達127種，作物類別則分為18類。配合此公告需研訂標準檢驗法以為執行檢驗與管理之依據，本計畫的目的為建立普伏松、芬殺松及加芬松之標準檢驗方法。普伏松之檢驗方法為檢體以丙酮抽取濃縮後將水層直接通入固相萃取管（Extrelut-20），再以每次20ml之石油醚或正己烷溶離2次回收佳且雜質較少，淨化則以8%去活化之矽酸鎂管柱經苯／二氯甲烷（1/2）溶離效果最佳。最後以氣相層析儀（G.C.-FPD）分析。敏感度5ppb。針對規定普伏松限量之農產品中作添加回收試驗，各農作物添加濃度為0.005、0.01及0.05ppm，其平均回收率範圍分別如下：米88.4%～91.4%,高麗菜79.7%～90.3%，小白菜72.0%～76.9%，茄子75.3%～81.0%，木瓜77.2%～81.7%。芬殺松分析以丙酮抽取檢體濃縮後將水層直接經固相萃取管（Extrelut-20）反抽於氯仿，萃取液經矽酸鎂快速層析管（Sepo-Pak Florisil cartridge）淨化，以乙醚／二氯甲烷（15/85）溶離，丙酮定量。可兼具回收及淨化效果。最後以氣相層析儀（G.C.-FPD）分析。敏感度50ppb。芬殺松方法於其規定限量之農產品中作添加回收試驗，米添加濃度為0.05、0.1及0.2ppm，其平均回收率範圍在88.0%～92.0%之間；香蕉（果肉）及芒果（果肉）添加濃度為0.25、0.5及1ppm，其平均回收率範圍香蕉（果肉）為82.1%～83.5%，芒果（果肉）77.0%～83.0%； 香蕉（果皮）及芒果（果皮）添加濃度為1、2、及4ppm，平均回收率範圍如下：香蕉（果皮）80.2%～88.8%，芒果（果皮）89.9%～97.0%。至於加芬松之檢驗方法為檢體經溶媒萃取，矽酸鎂快速層析管柱（Sep-Pak Florisil cartridge）淨化，最後以氣相層析儀（G.C.-FPD）分析。敏感度3ppb。針對規定加芬松限量之農產品中作添加回收試驗，檢體米、玉米及蘿蔔添加濃度為0.01、0.02及0.04ppm，其平均回收率範圍分別如下：米71.0～77.9%；玉米70.0～70.6%；蘿蔔81.9～86.6%。敏豆添加濃度為0.05、0.1及0.2ppm，其平均回收率範圍為75.3～81.0%。高麗菜添加濃度為0.1、0.2及O.4ppm，其平均回收率範圍為76.7 ～81.7%，小白菜、蕃茄、蘋果及胡瓜等作物添加濃度為0.25 、0.5及1.0ppm，其平均回收率範圍分別如下：小白菜101.1～109.6%；蕃茄78.1～81.8%；蘋果83.6～89.0%；胡瓜79.1～85.1%。

The gas-liquid chromatographic methods for determining residues of ethoprop, fenthion and carbophenothion were developped. The residues of these three pesticides were extracted from crops by homogenizing with acetone. To carry out the extraction and clean-up of pesticides from crude aqueous acetone extracts of the crops. Solid-matrix cartridges were used. The residues of the three pesticides were determined by GC-FPD. The detection limit of GC method for determination of ethoprop, fenthion and carbophenothion residues were 5.50 and 3ppb. The crude extracts for analyzing of ethoprop residues were transfered on to an Extrelut-20 column. The ethoprop was partitioned into hexane. and cleaned up by florisil column. Five crops which had been set with tolerance were each fortified with ethoprop standard at the levels of 0.005 ~ 0.05ppm, the average recoveries ranged from 72.0% to 90.3%. Fenthion residues were also extracted with acetone from crops and the extracts were poured to Extrelut-20-, and then partitioned by the mixture of diethyl ether and dichloromethane (15 / 85), then cleaned up by florisil cartridge. Three crops which had been set with tolerance were each fortified with fenthion standard at the levels of 0.05 ~ 4 ppm. the average recoveries ranged from 77.0% to 97.0% . For analyzing carbophenothion residues, the crude acetone extracts were partitioned with hexane The residues in hexane were cleaned up by florisil cartridge too. Nine crops which had been set with tolerance were each fortified with carbophenothion standard at the levels of 0.01 ~ 1ppm, and the average reconvenes ranged from 70.0% to 89.0%.