農產品中亞喜芬及本達隆殘留量之檢驗   全文下載

Analytical Methods for the Determination of Acifluorfen and Bentazone Residues in Crops

本研究發展出以高效液相層析法檢驗作物中亞喜芬（acifluorfen）及本達隆（bentazone）殘留量之方法，並進行市售乾豆類及米類計二十件農產品之抽樣調查。亞喜芬及本達隆屬弱酸性殺草劑，在鹼性下會解離而溶於水中，添加鹼性對偶離子試劑後形成複合物而溶於二氯甲烷中，本方法即利用此一選擇性對偶離子萃取技術來淨化檢體。亞喜芬以乙?及乙?：水（9:1, v／v）自作物中抽出，本達隆以丙酮抽出，減壓濃縮至無溶媒後以pH 8.0磷酸緩衝液溶出，以正己烷及二氯甲烷去雜質，添加鹼性對偶離子試劑後以二氯甲烷萃取，所得檢液以高效液相層析儀配合C18層析管及UV檢測器進行分析，亞喜芬於283 nm波長，本達隆於254 nm 波長偵測。添加亞喜芬於紅豆中，檢體濃度為0.05～0.15 ppm，所得平均回收率為91.6～97.6%，最低檢出限量為0.02 ppm；添加本達隆於白米及紅豆中，檢體濃度為0.25～0.75 ppm，所得平均回收率為88.6～91.7%，最低檢出限量為0.05 ppm。以建立之檢驗方法分析市售檢體，乾豆類十件並未檢出亞喜芬，而乾豆類及米類計十件亦未檢出本達隆。"

Methods using high performance liquid chromatography (HPLC) were developed to determine acifluorfen and bentazone in crops. Twenty samples of dry bean crops and rice were purchased from traditional markets and analyzed. Acifluorfen and bentazone being weak acids, were selectively extracted as ion pair compounds formed with tetrabutylammonium ion into dichloromethane under basic conditions. This technique was used for cleanup prior to determination of acifluorfen and bentazone by reverse phase liquid chromatography with UV detector. A residue of acifluorfen was extracted from crops with acetonitrile and acetonitrile-H20 (9:1, v/v) and a residue of bentazone was extracted from crops with acetone. The extracts were evaporated to dryness, dissolved in pH 8.0 phosphate buffer, and washed with nhexane and dichloromethane. Ion pair compounds were formed by adding tetrabutylammonium ion into an aqueous phase, and then extracted into dichloromethane. The dichloromethane phase was evaporated and the residues were dissolved in organic solvent and determined by HPLC. Recovery studies were carried out by spiking the standards of acifluorfen and bentazone at the levels of 0.05~0.15 and 0.25~0.75 ppm, respectively. The average recoveries were determined to be 91.6~97.6% and 88.6~91.7%, respectively. The detection limits in crops were 0.02 and 0.05 ppm for acifluorfen and bentazone, respectively. No residues of acifluorfen or bentazone were detected in dry bean crop samples, nor was bentazone residue found in rice samples. 本研究發展出以高效液相層析法檢驗作物中亞喜芬（acifluorfen）及本達隆（bentazone）殘留量之方法，並進行市售乾豆類及米類計二十件農產品之抽樣調查。亞喜芬及本達隆屬弱酸性殺草劑，在鹼性下會解離而溶於水中，添加鹼性對偶離子試劑後形成複合物而溶於二氯甲烷中，本方法即利用此一選擇性對偶離子萃取技術來淨化檢體。亞喜芬以乙腈及乙腈：水（9:1, v／v）自作物中抽出，本達隆以丙酮抽出，減壓濃縮至無溶媒後以pH 8.0磷酸緩衝液溶出，以正己烷及二氯甲烷去雜質，添加鹼性對偶離子試劑後以二氯甲烷萃取，所得檢液以高效液相層析儀配合C18層析管及UV檢測器進行分析，亞喜芬於283 nm波長，本達隆於254 nm 波長偵測。添加亞喜芬於紅豆中，檢體濃度為0.05～0.15 ppm，所得平均回收率為91.6～97.6%，最低檢出限量為0.02 ppm；添加本達隆於白米及紅豆中，檢體濃度為0.25～0.75 ppm，所得平均回收率為88.6～91.7%，最低檢出限量為0.05 ppm。以建立之檢驗方法分析市售檢體，乾豆類十件並未檢出亞喜芬，而乾豆類及米類計十件亦未檢出本達隆。