Calibration Transfer for Solving the Signal Instability in Quantitative Headspace-Mass Spectrometry

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• 作者：José ; Luis Pé ; rez Pavó ; n ; Miguel del Nogal Sá ; nchez ; Carmelo Garc&iacute ; a Pinto ; M Esther Ferná ; ndez Laespada ; and Bernardo Moreno Cordero
• 刊名：Analytical Chemistry
• 出版年：2003
• 出版时间：November 15, 2003
• 年：2003
• 卷：75
• 期：22
• 页码：6361 - 6367
• 全文大小：88K
• 年卷期：v.75,no.22(November 15, 2003)
• ISSN：1520-6882

文摘

It is reported that calibration transfer is able to compensate the variations in sensitivity in direct coupling of aheadspace sampler to a mass spectrometer when usedfor quantification purposes using multivariate calibrationtechniques. This strategy of signal stability compensationallows the use of models constructed from large calibration standard sets without having to repeat their measurement even though variations occur in sensitivity, whichmay or may not be constant along the mass range. Thistechnique offers advantages over the use of internalstandards in this methodology and only requires themeasurement of a small number of transfer samples witheach set of unknown samples. The results obtained in thedetermination of six volatile organic compounds-benzene,toluene, ethylbenzene, and m-xylene (BTEX), methyl tert-butyl ether (MTBE), and mesitylene-are reported. Toobtain an appropriate calibration set, a Plackett-Burmandesign with five levels of concentration for each component was employed. A PLS multivariate calibration modelwas constructed with a group of 25 samples. For selectionof the optimum number of principal components, anexternal validation set (5 samples) was used and theprediction capacity of this set was checked with anadditional group of samples that had not been used eitherin the construction or in the validation of the model. Theresults obtained can be considered highly satisfactory, andthe methodology was successfully tested with naturalmatrixes (river and tap water).