以鹽析輔助式液液萃取法結合線上衍生氣相層析質譜儀檢測水樣中之消毒副產物鹵乙醯胺

陳姿陵(Tzu-ling Chen)

指導教授 ： 丁望賢

國立中央大學/理學院/化學系/碩士(2014年)

摘要

消毒副產物是由消毒劑與水中之有機物質反應而得，雖然消毒劑可將水中之致病菌有效的消滅，但消毒副產物卻會危害人體的健康，而鹵乙醯胺(Haloacetamides,簡稱HAcAms)就是其中一種。在USEPA 的研究報告中已指出HAcAms 的誘發突變性及致癌的風險皆遠高於三鹵甲烷、鹵乙酸和亞硝胺(Nitrosamines)等消毒副產物，但針對HAcAms 尚未制訂明確的限制含量。
本實驗利用鹽析輔助式液液萃取法(Salting-out assisted liquid-liquid
extraction,簡稱SALLE)做為樣品前處理方法，並搭配線上(on-line)衍生氣相層析質譜儀(GC-MS)來檢測五種鹵乙醯胺(CAcAm、DCAcAm、BAcAm、
BCAcAm、DBAcAm)在水樣中的濃度。線上矽烷化衍生條件之最佳化為：取1 μL 的MTBSTFA+1%TBDMSCl 矽烷化衍生試劑加入10 μL 經前處理所得的萃取液和1 μL 內標準品溶液中，注射埠設定為90℃下進行衍生化，可以得到良好的矽烷化衍生效果，在10-1000 μg/L 的濃度範圍內，檢量線迴歸係數皆大於0.995。
鹽析輔助式液液萃取法最佳化結果為：以4 mL 乙酸乙酯快速注入含有3 g 硫酸鈉的10 mL 水樣中，經過1 分鐘的振盪後，再以4000 rpm 速率離心5 min，使有機層與水層分開。取出萃取液後，藉由通過無水硫酸鈉管柱除去水分，並以氮氣吹至100 μL，最後取10 μL 待測物溶液和1 μL 的內標準品溶液利用大體積樣品導入裝置進行線上矽烷化衍生後以GCMS來進行檢測，偵測極限為0.01-0.1 μg/L。對其做精密度及準確度的測試，其相對標準偏差(RSDs)皆小於15%，顯示此方法具有良好的再現性。利用標準添加法在不同的水樣中測定的總濃度介於0.16 至0.77 μg/L。

關鍵字

氣相層析質譜儀 ； 消毒副產物 ； 線上衍生化

並列摘要

Disinfection by-products (DBPs) are formed by the reaction of disinfectants with natural organic matters in water. Disinfection is an intended means of trying to kill pathogens in various water supplies, however DBPs cause health risks to human. Haloacetamide (HAcAm) is one of the most toxic nitrogenous disinfection by-products (N-DBPs) that raises concern for public health. In the US-EPA, HAcAms have been reported to be much higher cytotoxicity and genotoxicity than currently regulated trihalomethanes (THMs), haloacetic acids (HAAs) and nitrosamines, but the drinking water guideline has not yet been established for these N-DBPs.
In this study, salting-out assisted liquid-liquid extraction (SALLE) coupled with on-line derivatization and gas chromatography-mass spectrometry (GC-MS) method was developed and applied for the first time to determine five HAcAms: CAcAm, DCAcAm, BAcAm, BCAcAm and DBAcAm, in aqueous samples. The optimized on-line derivatization involved the adding 1 μL of N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tert-Butyldimethylchlorosilane (MTBSTFA+1% TBDMSCl) reagent to a 10 μL extract (with 1 μL internal standard) from the water sample, which gave an excellent yield of the TBDMS-derivatives of analytes at injection-port temperature of 90 ℃. The linearities of analytes were achieved in the range of 10-1000 μg/L with coefficients of determination (r2) exceeded 0.995.
The optimal conditions of SALLE involved the rapid injection of 4.0 mL of ethyl acetate into 10 mL of water sample containing 3 g of sodium sulfate in a sample tube. After shaking extraction for 1 min and centrifugation at 4000 rpm
(5min), the upper layer was passed through sodium sulfate anhydrous column and evaporated to 100 μL. The extract 10 μL was directly determined by on-line derivatization-GC-MS. The limits of quantitation (LOQs) were 0.01-0.1 μg/L.
Reproducibility was obtained with relative standard deviation (RSDs) better than 15%. The total concentration of these HAcAms in the water samples ranged from 0.11 to 3.81 μg/L.

參考文獻

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