以含超低濃度界面活性劑的水作為分散劑輔助乳化液液微萃取法分析水樣中的有機氯農藥

Water with ultra-low concentration of surfactant as dispersed solvent-assisted emulsion dispersive liquid-liquid microextraction for the determination of organochlorine pesticides in aqueous samples

李翊(Li, Yee)

指導教授 ： 黃賢達

國立清華大學/理學院/化學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00205

摘要

隨著環保意識的抬頭，永續發展概念的興起，綠色化學已逐漸成為重要的課題。為了要監控環境中有害物質，必須借助於各種分析技術。近年來分散液液微萃取法 (Dispersive liquid-liquid microextration; DLLME) 發展尤為快速，擁有實驗過程簡單、快速，成本較低等優點。但使用大量有機物做為分散劑造成環境負擔，且會增加萃取溶劑與分析物溶解於水中，所以本篇論文將開發新的以含極低濃度 (1 mgL－1) 界面活性劑的水做為分散劑，輔助少量萃取溶劑 (10~12 μL) 以微量注射針10秒內來回抽取四下進行乳化，再注入水樣中進行萃取，搭配本實驗室開發的改善溶劑收及系統，選用不含鹵素且極低毒性的萃取溶劑，串聯氣相層析儀搭配電子捕捉偵測器 (GC-ECD) 分析水樣中的Heptachlor (飛佈達)、α-Endosulfan (α-安殺番)、p, p′-DDE (p, p′-滴滴依)、o, p′-DDD (o.p'-滴滴滴)、 Endrin (安特靈) 五種常見有機氯農藥。開發出靈敏、簡單、快速及對環境較友善的前處理結合濃縮、萃取的方法，並對於目前所使用的方法進行比較。
於第一個研究中，我們以12 μL dodecyl acetate為萃取溶劑，在最佳化條件下，線性濃度範圍有5~5000 ngL－1，決定係數皆在0.9963以上，方法偵測極限為1~5 ngL－1，定量偵測極限為3~17 ngL－1。單一天的精密度在6.1~12.9 % 之間，連續六天精密度在9.7~14.4 % 之間，濃縮倍率介於1901~3530之間，用此開發方法偵測湖水中絕對回收率為20.8~43.5 %，相對回收率為83.2~109.8 %，精密度範圍在7.1~14.8 %，海水中絕對回收率為19.9~49.2 %、相對回收率為85.4~115.9 %，精密度範圍在3.0~13.6 %。
於第二個研究中，我們以10 μL 2-dodecanol為萃取溶劑，在最佳化條件下，線性濃度範圍有1~10000 ngL－1，決定係數皆在0.9970以上，方法偵測極限為0.5~2 ngL－1，定量偵測極限為1.7~6.7 ngL－1。單一天的精密度在4.0~5.1 % 之間，連續六天精密度在5.0~10.3 % 之間，濃縮倍率介於1881~3108之間，用此開發方法偵測海水中絕對回收率為25.7~42.2 %，相對回收率為96.3~111.2 %，精密度範圍在1.2~8.5 %，溪水中絕對回收率為22.4~41.9 %、相對回收率為90.7~107.9 %，精密度範圍在1.4~6.4 %。
實驗證明，我們所開發的是一種簡單、快速的萃取方法，利用甚少量、便宜、毒性低、不含鹵素的萃取溶劑，使用對環境友善的且濃度極低用量很少含界面活性劑的二次水做為分散劑，在極短時間內即可乳化完全，並搭配氣相層析儀和電子捕捉偵測器，可有極低偵測極限及極高的濃縮倍率。本實驗應用在湖水、海水及溪水上得到不錯的回收率及精密度，是一個對環境樣品極為方便且實用性高的前處理方法。

關鍵字

界面活性劑 ； 分散液液微萃取法 ； 有機氯農藥 ； 氣相層析儀 ； 改善溶劑收集系統

並列摘要

The conscious of environmental protection is beginning to wake up. The harmful materials are also starting to be forbidden and diminished. Besides, the complicated matrix of environmental samples and trace amount of analyte make up placing importance on the preconcentration technique. In recent years, dispersed liquid-liquid microextraction (DLLME) has been developed particularly rapid, which experimental process is simple, fast, and low cost … and so on. But it used a lot of organic matter as dispersed solvent which can cause environmental burden and increase the extraction solvent with the analyte dissolved in the water. In this studty, we replace large amounts of organic to water containing very low concentration (1 mgL－1) of surfactant as the dispersed solvent which assisted a small amount of extraction solvent (10~12 μL) to emulsion. We used microinjection needle back and forth four times to mix within 10 seconds and then injected into water samples for extraction. We select low toxic non-chloro extraction solvent by using the improved solvent collection system (ISCI) which developed in our laboratory. And than use gas chromatography with electron capture detector (GC-ECD) to analye five common organochlorine pesticides like heptachlor, α-Endosulfan, p,p'-DDE, o,p'-DDD, Endrin in water sample. Developed a pre-treatment combined with enrichment extraction method which is sensitive, simple, fast and more environmentally friendly and used to compare with another methods.
In the first study, we used dodecyl acetate (12 μL) as the extraction solvent. Under optimized conditions, the results indicate that linear range of the method was 5~5000 ngL－1 with the R2 ≧0.9963, the method detection limit from 1 to 5 ngL－1, the quantitative detection limit from 3 to 17 ngL－1. The precision for inter-day was within 6.1~12.9 %. The precision for intra-day was within 9.7~14.4 %, the enrichment factor between 1901 and 3530. In lake water, the absolute recoveries were within 20.8~43.5 %, the relative recoveries were within 83.2~109.8 %, the precision from 7.1 % to 14.8 %. In sea water, the absolute recoveries were within 19.9~49.2 %, the relative recoveries were within 85.4~115.9%, the precision from 3.0 % to 13.6 %.
In the second study, we used 2-dodecanol (10 μL) as the extraction solvent. Under optimized conditions, the results indicate that linear range of the method was 1~10000 ngL－1 with the R2 ≧0.9970, the method detection limit from 0.5 to 2 ngL－1, the quantitative detection limit from 1.7 to 6.7 ngL－1. The precision for inter-day was within 4.0~5.1 %. The precision for intra-day was within 5.0~10.3 %, the enrichment factor between 1881 and 3108. In sea water, the absolute recoveries were within 25.7~42.2 %, the relative recoveries were within 96.3~111.2 %, the precision from 1.2 % to 8.5 %. In stream water, the absolute recoveries were within 22.4~41.9 %, the relative recoveries were within 90.7 ~107.9 %, the precision from 1.4 % to 6.4 %.
We developed a simple, rapid method of extraction. We used very small amount of volume, cheap, low toxicity, halogen-free extraction solvent and used water which was environmentally friendly, very low amount of volume, containing very low concentrations of surfactants as a dispersed solvent. It can be emulsified completely in a very short period of time. The method has very low detection limit and a high enrichment factor. The application of this experiment on the lake, sea and stream water with good recovery and precision. This method provided very convenient and high availability pre-treatment methods in environmental samples.

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