本研究探討以氣相層析儀附電子捕獲式檢出器檢測水、土中甲基合氯氟殘留量之方法。甲基合氯氟推薦於防治柑桔園雜草，其在水、土中之殘留情形在台灣尚未被探討。分別以溶劑萃取法及固相萃取法進行水中甲基合氯氟之含量分析，結果以固相萃取法之偵測敏感度較佳，且操作上可提高分析效率。本研究利用固相萃取法進行水中甲基合氯氟之含量分析；利用丙酮將土壤中之甲基合氯氟抽出，再以C18萃取管淨化，以氣相層析儀檢測。甲基合氯氟之線性迴歸係數為0.992，分別添加5及10μg/L之標準品於水中進行回收率試驗，平均回收率分別為90.7及93.1%。分別添加0.08及0.16mg/Kg之標準品於土壤中進行回收率試驗，平均回收率分別為89.1-91.4%。水中之偵測界限為0.06μg/L，土中之偵測偵測界限為1.48μg/Kg，以建立之方法分析柑桔園土壤及柑桔園下方蓄水池水中之甲基合氯氟殘留，結果皆未檢測出甲基合氯氟。柑桔園使用之甲基合氯氟污染水源之可能性低。

A precise method was developed for detecting the residues of haloxfop-methyl by gas liquid chromatography (GLC) with electron capture detector. Haloxyfop-methyl is used for weed control in citrus orchard in Taiwan. The residues of haloxyfop-methyl in water and soil have not been studied in Taiwan. Solid-phase extraction followed by GLC techniques was used for the monitoring of haloxyfop-methyl in water. Soil samples were extracted with acetone, the extract was then cleaned up using C18 cartridge before being subjected to GLC analysis. The correlation coefficient of the linear standard curves of haloxyfop-methyl was 0.992. Recovery of haloxyfop-methyl in water were as in the 90.7-93.1% range. Recovery of haloxyfop-methyl in soil was in the 89.1-91.4% range. The detection limit of haloxyfop-methyl in water and soil were 0.06μg/L and 1.48μg/Kg, respectively. This study was conducted to investigate the residues of water and soil following herbicide application. Water samples collected from pond lower of the citrus orchard. No residue of haloxyfop-methyl was detected in water and soils which were sampled from citrus orchard.