大體積固相微萃取水中揮發性有機污染物

Large Volume Solid Phase Microextraction of Volatile Organic Compounds in Aqueous Sample

陳元曼(Yuan-Mam Chen) ； 王家麟(Jia-Lin Wang)

《化學》 61卷2期 (2003/06) Pp. 189-198

https://doi.org/10.6623/chem.2003020

摘要

固相微萃取（Solid Phase Micro Extraction；SPME）為近年來發展迅速之免溶劑萃取技術，目前也廣泛應用在許多液體樣品的分析上，SPME具有快速、省時、不需使用任何有機溶劑及符合經濟效率的優點，但有鑒於氣相層析儀（Gas Chromatography; GC）注射埠只能允許針筒插入進樣。因此商業化SPME必須以針筒方式設計。本實驗利用增加靜相的體積，以提高分析物的萃取量，以及利用SPME的概念自行塗佈poly dimethylsiloxane（PDMS）高分子薄膜，其成份接近於商業化SPME的吸附靜相，再配合自行研發之進樣裝置，使熱脫附分析物不再侷限於GC之注射埠，因此大幅降低偵測極限，惟塗佈上交聯過的PDMS固相萃取棒熱脫附之後產生固定矽烷分子破片。在實驗過程中自行設計了一套熱脫附進樣系統，再連續9次的分析50 μg/L（ppb）濃度之benzene、toluene、ethylbenzenen、m-xylene、o-xylene（BTEX）樣品，其再現性約達RSD4%～12%左右，與商業化SPME萃取裝置比較，在相同萃取條件下咱製大體積PDMS裝置無論對於標準樣品或真實水樣在層析圖譜上的表現幾乎完全相同但在感度表現上高出數十倍以上。

關鍵字

poly dimethylsiloxane(PDMS) ； 大體積固相萃取

並列摘要

Sold phase microextraction ( SPME ) has grown wide popularity in recent years in analyzing volatile or semi - volatile organic compounds in aqueous samples due to its ease of use, adequate sensitivity, solvent free in extraction, etc. The most attractive advantage with SPME over other means of extraction lies in the fact that no solvent is needed in the extraction procedure, the polymer phase coated on a thin fused silica fiber is employed as the extraction media to absorb organic analytes in aqueous samples. Subsequently, the fiber is inserted in the GC injection port to rapidly thermal desorb the analytes onto the column. Assuming the volume of the polymer phase is negligible compared to that of the aqueous phase, the sensitivity of this technique is proportional to the volume of the polymer phase Nevetheless, the geometry of regular GC injector forbids any forms of sample introduction other than needle type of insertion, as which the commercial SPME device is configured. To further lower the detection limit of SPME the injection port has to be redesign to accommodate a polymer phase of significant larger volume than the commercial SPME fiber In this study, a thick film of polydimethylsiloxane ( PDMS ) polymer was coated on a glass rod of 2 mm O.D. x 6.7cm length. A renovated thermal desorption device was designed and constructed to accommodate the thick PDMS rod. Furthermore, to avoid peak broadening in chromatography, a micro trap packed with chemical sorbents was employed to focus analytes desorbed from the volume of PDMS, which resulted in comparable peak width but significantly higher peak response than the commercial SPME. Based on the analysis of standards containing 50 ug / L of benzene, toluene, ethylbenzene, xylene and various true underground water samples, the self prepared large volume PDMS and accompanying device is several tens fold to 2 order of magnitude in sensitivity enhancement.

並列關鍵字

poly ； dimethylsiloxane(PDMS) ； Large Volume Solid Phase Microextraction