Area normalization with response factor

Area Normalization with Response Factors. If standards are available, the third limitation can be removed by running the standards to obtain correction factors or so-called relative response factors /. One substance (it can be an analyte in the sample) is chosen as the standard, and its response factor /s is given an arbitrary value like 100. Mixtures, by weight, are made of the standard and the other analytes, and they are chromatographed. The areas of the two peaks—As and Ax for the standard and the unknown, respectively—are measured, and the relative response factor of the unknown, fx, is calculated ... 

Area Normalization with Response Factor (ANRF). The area percentages are corrected for the detector characteristics by determining response factors. This requires preparation and analysis of standard mixtures. 

ANRF Area normalization with response factors... 

ANRF area normalization with response factors CRF chromatographic response function... 

The mass concentration of each component is determined by area normalization with response factors. Peaks eluting after /t-nonane are summed and reported as C,o+. 

Chemical Analysis of Extracts. The extracts were analyzed by capillary column GC-MS for OCs, TAAPs, and PAHs (see the list on page 313). The GC-MS parameters used at the two laboratories are shown in Table II. The identification and quantitation were all done by using automatic routines based on a mass spectra library created from authentic standards of the selected compounds. Compounds were located by searching the reconstructed ion chromatogram for each library entry within a narrow retention time window relative to the internal standard (anthracene-dio or phenanthrene-dio). Quantitation was achieved by comparison of characteristic ion areas in the field samples with ion areas of the internal standard. These ion areas were normalized by response factors established by comparison of ion ratios of a standard mixture of all 66 analytes at a concentration of 2.5 ng//zL. 

Normalized area percent calculation with response factors. 

With care internal normalization can be used where peak size is measured by height instead of area, though this is rare. The response factor is now subject to slight variations in column temperature, injection technique, carrier flow, and the like, all mentioned under peak height measurement previously. This approach requires that the standard mix for response factors to be run as close in time to the unknown as possible and new response factors to be determined each time. Note also that response factors determined from area measurement in no way are the same for those determined from peak height. 

As a result of limited sensitivity and restricted linear dynamic range, the refractive index detector is often a "choice of last resort" and is used for those applications where, for one reason or another, all other detectors are inappropriate or impractical. However, the detector has one particular area of application for which it is unique and that is in the separation and analysis of polymers. In general, for those polymers that contain more than six monomer units, the refractive index is directly proportional to the concentration of the polymer and is practically independent of the molecular weight. Thus, a quantitative analysis of a polymer mixture can be obtained by the simple normalization of the peak areas in the chromatogram, there being no need for the use of individual response factors. The sensitivity of most RI detectors will be about 1 x 10 g/ml and the linear dynamic range around 1 x 10 to 2 X 10 4 g/ml with the response index (r) lying between 0.97 and 1.03. 

The quantification is based on multi level response factors covering both differences in extraction behaviour, volatility and GC/MS response of the compounds and of the deuterated internal standards. 1 Utre pentane washed water is spiked with 50 pg deuterated internal standards and normally 1,5,25 and 100 pg of the different target compounds. Calibration curves are automatically calculated and stored on the disk, and quantification is based on area of ion chromatogram of one specific mass for each compoimd. 

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