尿中烷氧基醋酸分析方法研究

Method Development of Urinary Alkoxy Acetic Acids

本研究在於簡化現有乙二醇醚溶劑暴露勞工生物偵測技術之樣品前處理步驟，改善分析方法之特異性與可靠性，以氣相層析/質譜儀研發出新的尿液中烷氧基醋酸分析方法。將含有乙二醇醚溶劑之主要毒性代謝物烷氧基醋酸之尿液檢體，加入少量鹽酸，以二氯甲烷與異丙醇之混合溶劑進行萃取，再以氣相層析/質譜儀分析。研究結果顯示在0.3 - 200 μg/mL濃度範圍內，當生物檢體之pH值調整至1.05-1.45之間、二氯甲烷與異丙醇之混合體積比例選擇2:1、且萃取時間超過5 分鐘以上，即可獲得最佳之樣品前處理條件。甲氧基醋酸、乙氧基醋酸及丁氧基醋酸之整體變異係數分別為5.55%、6.37%、及6.41%。在 - 20 oC 低溫下，尿液檢體可以有效保存至少五個月，經過三次連續之解凍、冷凍步驟後，樣品亦未發生變化。甲氧基醋酸、乙氧基醋酸、及丁氧基醋酸之偵測極限值分別為0.055、0.183、及0.009 μg/mL。甲氧基醋酸與乙氧基醋酸並無顯著之基質效應，而丁氧基醋酸之基質效應則較大。品質管制之盲樣樣品平均回收率為99-101%。19 位銅箔積板製造業現場暴露勞工之尿液檢體分別以新方法與文獻上之參考分析方法進行方法比較，發現二者線性相關係數高達0.999，斜率為1.01，平均濃度差異為 -1.48 μg/mL，測定濃度範圍為3.57 - 228 μg/mL。本研究證實這項新的不須衍生反應的前處理步驟，配合氣相層析/質譜儀，可以提供職業性勞工乙二醇醚溶劑暴露一項特異、靈敏、簡單、可靠之生物偵測技術。

The purposes of this study are to simplify the current sample preparation procedures, and to improve the specificity and reliability of the conventional analytical methods to measure urinary alkoxy acetic acids (AAAs). Samples containing AAAs including methoxy, ethoxy, and butoxy acetic acids (MAA, EAA, and BAA) were acidified with hydrogen chloride and extracted with a mixed solvent of methylene chloride (MC) and isopropyl alcohol (IPA), then analyzed by gas chromatography/mass spectrometry (GC/MS). Optimal results were obtained when pH was 1.05-1.45, ratio of MC and IPA was 2:1, and when extraction time was longer than 5 min. Over the concentration range of 0.3 to 200 μg/mL, MAA, EAA, and BAA could be determined with a pooled coefficient of variation of 5.55%, 6.37%, and 6.41%, respectively. Urine samples were stable for at least 5 months and 3 freeze-thaw cycles at - 20 oC. The limits of detection of MAA, EAA, and BAA were 0.055, 0.183, and 0.009 μg/mL, respectively. The matrix effects were negligible for MAA and EAA, but were marginally significant for BAA. The average recoveries of AAAs were 99- 101%. Urine samples from 19 exposed workers showed a strong correlation (r = 0.999, slope = 1.01) between the new GC/MS method and a reference method. The mean concentration difference ( d ) was -1.48 μg/mL over the concentration range of 3.57 to 228μg/mL. The simplified non-derivatization sample pretreatment procedures coupled with GC/MS can provide a specific, sensitive, simple, and reliable method for the biological monitoring of occupational exposure of ethylene glycol ethers.