甲基異丁酮為國內工業界上常用之有機溶劑，且尿中甲基異丁酮濃度目前已被建議為勞工甲基異丁酮暴露之生物暴露指標。本研究將含有甲基異丁酮之尿液檢體以頂空技術 (head-space technique)進行前處理，再以氣相色層分析儀及離子火燄偵測器進行定量分析。研究結果顯示最佳之前處理條什為加熱溫度80℃，加熱時間為15分鐘，同時添加之碳酸鉀為2.50克。檢量線濃度範圍為0.16至25.60μg/mL，六條同日與異曰之檢量線相關係數均高於0.999，各濃度之平均變異係數均小於9.10%。尿液樣品貯存膨-200C時，其穩定性能維持22天左右。本方法之偵測極限與可量化偵測極限分別為0.024和0.082μg /mL。添加回收率為95.80 ±3.87%。現場勞工真實尿液檢體測試結果，顯示本分析方法能應用於作業場所勞工甲基異丁酮暴露評佔。本研究巳成功的建立簡單、靈敏且可靠之甲基異丁酮職業性暴露之生物偵測分析方法。

　　　　　Methyl isobutylketone is widely used as organic solvent in industries. Urinary methyl isobutyl ketone has been recommended as a good biomarker of exposure for methyl isobutyl ketone. In this study, urine samples containing methyl isobutyl ketone was treated by the head-space technique, then was analyzed by gas chromatography combined with a flame ionization detector. The optimal results were obtained when the heating temperature was 80~C, the heating time was 15 minutes, and when 2.5 gm of potassium carbonate was added in the head-space sample pretreatment procedure. The correlation coefficients of 6 inter-day and 6 intra-day calibration curves of methyl isobutyl ketone were greater than 0.999 and the pooled coefficients of variance were less than 9.10 % over the concentration range of 0.16 to 25.60 μg/mL. Urinary methyl isobutyl ketone was stable for at least 22 days at -20~C. The limit of detection and the limit of quantitation were 0.024 and 0.082 μg/mL, respectively. The recovery of methyl isobutyl ketone was 95.80-1-3.87 %. Analysis of urine samples from exposed workers demonstrated that the proposed method is applicable to real samples in field study. It is therefore concluded that the established modified method is a sensitive, simple, and reliable method for the biological monitoring of occupational exposure to methyl isobutyl ketone.