阿達瑪進樣器的設計及其在氣相層析質譜法對揮發性有機物偵測上的應用

Design of a Novel Hadamard-Injector and Its Application to VOCs (Volatile Organic Compounds) Detection Based on Gas Chromatography/Mass Spectrometry

范貞貞(Zenzen Fan)

指導教授 ： 林震煌

國立臺灣師範大學/理學院/化學系/碩士(2009年)

摘要

本研究設計並製造一個新型阿達瑪進樣器（Hadamard injector），能使待分析的揮發性有機物（volatile organic compounds, VOCs）依據阿達瑪序列（Hadamard code）注射到氣相層析質譜儀（gas chromatography/mass spectrometry）中。配合阿達瑪轉換（Hadamard transformation）技術，相較於傳統的單一注射方式，能更有效地提高訊號的雜訊比值（signal-to-noise ratio）。此阿達瑪進樣器本身構造類似脈衝噴嘴（pulse nozzle），可由電腦控制開放的時間與樣品進入氣相層析氣化管（inlet liner）的量。視實驗情況所需，氣態樣品的單一注射量可控制在30 nL ~ 3 mL之間。同日與異日的RSD（related standard deviation）值分別為0.24 ~ 0.38%及0.27%，顯示本進樣器具有極佳的再現性。本實驗亦詳細探討氣相層析分離時進樣時間、進樣量與分流比等因素對阿達瑪轉換效率的影響。在最佳化進樣條件下，當測試樣品以阿達瑪序列次數為255、511、1023次分別進行實驗時，雜訊比值可得到7.7、10.8、14.8倍的改良效果。這樣的增加倍率與理論值（8.0、11.3、16.0）相當吻合。最後，本研究也對真實樣品進行實際偵測。將10.0 L的實驗室內空氣，以抽氣採樣方式，經活性碳吸附後，加熱脫附之同時，以阿達瑪進樣器將空氣樣品注射到氣相層析氣化管中，實際分析化學實驗室內揮發性有機物。實驗結果發現，有阿達瑪進樣器之協助，空氣中即使含有低濃度的丙酮、二氯甲烷及己烷，亦能輕易地被檢驗出來。

關鍵字

阿達瑪轉換 ； 阿達瑪進樣器 ； 揮發性有機物 ； 氣相層析質譜法

並列摘要

A novel Hadamard-injector was well designed and successfully used for the detection of VOCs (volatile organic compounds) based on gas chromatography/mass spectrometry (GC/MS). Compared to a single injection used in most of GC/MS, the inverse Hadamard transformation of the encoded chromatogram can make the signal-to-noise (S/N) ratios of signals improve substantially. Herein, the Hadamard-injector was modified from a regular pulse nozzle, where a personal computer was used to control the open timing and sample injection volume (into the GC inlet liner). Depending on the experiment conditions, the injected volume of gas sample can be controlled in the range of 30 nL ~ 3 mL. The RSD (related standard deviation) values of within-day and between-day were determined to 0.24 ~ 0.38% and 0.27%, respectively, indicating its stability and reproducibility. Furthermore, the sample injection time, volume and split-ratio were investigated in detail during GC separation experiments. Under the optimized conditions, when the Hadamard matrices of 255, 511 and 1023 were used, the S/N ratios of the signals were substantially improved to 7.7-, 10.8- and 14.8-fold, respectively, matched with those expected from theoretical values (8.0-, 11.3- and 16.0-fold). Finally, the Hadamadrd injector was also examined by a real sample. A 10.0 L air (in a chemistry laboratory) was sampled by means of an activated-charcoal trapper. After a period of time, the trapper was heated and the condensed sample was injected into the inlet liner by the Hadamadrd injector. The findings show that acetone, dichloromethane and hexane were easily determined from the air sample, even at low concentration levels.

並列關鍵字

Hadamard ； VOC ； GC/MS

參考文獻

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