Trace quantitative analysis

It is crucial in quantitative GC to obtain a good separation of the components of interest. Although this is not critical when a mass spectrometer is used as the detector (because ions for identification can be mass selected), it is nevertheless good practice. If the GC effluent is split between the mass spectrometer and FID detector, either detector can be used for quantitation. Because the response for any individual compound will differ, it is necessary to obtain relative response factors for those compounds for which quantitation is needed. Care should be taken to prevent contamination of the sample with the reference standards. This is a major source of error in trace quantitative analysis. To prevent such contamination, a method blank should be run, following all steps in the method of preparation of a sample except the addition of the sample. To ensure that there is no contamination or carryover in the GC column or the ion source, the method blank should be run prior to each sample. 

R. Boyd, R. Bethem, C. Basic and D. Matthews, Trace Quantitative Analysis by Mass Spectrometry, J. Wiley Sons, New York, 2008. 

Boyd, R.K., Basic, C., Bethem, R.A. Trace Quantitative Analysis by Mass Spectrometry. Wiley, Chichester (2008)... 

R. K. Boyd C. Basic R. A. Bethem, Trace Quantitative Analysis by Mass Spectrometry, John Wiley and Sons Chichester, UK, 2008. 

The determination of xq for a given detector response, yo> is, of course, the most important outcome of trace quantitative analysis. Xq, together with an estimate of its degree of uncertainty, represents the ultimate goal of trace quantitative analysis, that is, it answers the question How much of analyte i is present and how reliable is this number in a given environmental sample For TEQA, it is usually unlikely that the population mean for this interpolated value /a(xo) can ever be known and that the standard deviation in this population mean, [Pg.40]

Trace Quantitative Analysis by Mass Spectrometry Robert K. Boyd, Cecilia Basic, Robert A. Bethem 2008 John Wiley Sons, Ltd. ISBN 978-0-470-05771-1... 

The upper limit on the molecular mass of analytes that are amenable to trace quantitative analysis is currently considered to be 2000u (Da). This is the result of several factors, some of which are intrinsic to the problem, e.g., the relative abundances of higher isotopologs that increase significantly with increasing mass, and result in dilution of the total ion current derived from the analyte over too many m/z values. 

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