內部標準在氣相層析質譜儀分析揮發性有機物效能探討

None

蘇源昌(Yuan-Chang Su)

指導教授 ： 王家麟

國立中央大學/理學院/化學系/碩士(2006年)

摘要

中文摘要
以固態的化學吸附劑做為濃縮方法，再利用GC/FID做為分離偵測的儀器，為現今偵測碳氫化合物最廣為使用的分法之ㄧ，而利用GC/MS作為偵測儀器，更能夠解決GC/FID對於複雜VOCs定性上的困難。
但由於空氣進樣的變動性以及MS本身的訊號飄移較一般GC偵測器明顯，對於定量的結果往往造成較大的誤差，影響再現性，故在此討論自行開發重量法配置標準品方法，作為GC/MS線上分析之內標。每次進樣皆以固定濃度的方式將內標導入前濃縮系統，再以面積比例(VOC面積/內標準品面積)的方式修正儀器誤差，如此可在儀器及系統較不穩定時，將RSD值由7%~8%降低至2%-3%之間，而所製作的檢量線R2值可達到0.990~0.999之範圍。
在量測VOCs新系統的開發上，嘗試將二重層析(heart-cut)技術連接於GC/MS上，運用PLOT 管柱與DB-1 管柱的相互搭配，同時對C3~C12的VOCs物種進行定性與定量的分析，解決以往MS只能使用單一管柱分局部物質的限制，使未來的監測站能夠對於VOCs物種的測量提高定性的能力。

關鍵字

內部標準 ； 質譜儀

並列摘要

Abstract
Using chemical sorbents for enrichment and GC/FID for analysis is the most popular technique to analyze volatile organic compounds (VOCs) nowadays. Nevertheless, using GC/MS is even more versatile than GC/FID for its powerful compound identification capabilities.
Due to the larger instability associated with the MS detector than FID, poorer reproducibility is often observed when using GC/MS for VOC analysis instead of GC/FID. Using internal gas standards in GC/MS analysis can be an effective means to reduce instrumental instability. As a result, this study involves preparation of gas standards by the gravimetric method and the utilization of these gas standards for internal calibration in GC/MS analysis. The calibration method and the construction of an automated on-line enrichment system with internal standard addition are discussed. Improved analytical precision from 7~8% RSD to 2~3% was achieved. Linearity denoted by the correlation coefficient (R2) of the completed system was in the range of 0.990~0.999.
The second part of the study involves devising a heart-cut system for on-line analyzing ambient VOCs by GC/MS. Illustration and test results of integrating duel columns of a PLOT and a DB-1 to a heard-cut device coupled to a single MS detector in order to analyze C2-C12 species simultaneously are discussed, which previously was not possible and could only be performed by 2 separated detectors for the duel columns. This heart-cut GC/MS system once completed will be employed in a monitoring station for monitoring VOC species which are difficult to be identified or measured by conventional flame ionization detection.

並列關鍵字

none

參考文獻

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