Chromatography quantitative peak information

The problem is to sort through and retrieve information from the large amount of quantitative data produced with capillary chromatography. After those peaks that contain the most information that describes the sample have been determined, directed and specific confirmation analysis by GC/MS may occur. 

In chromatography the quantitative or qualitative information has to be extracted from the peak-shaped signal, generally superimposed on a background contaminated with noi%. Many, mostly semi-empirical, methods have been developed for relevant information extraction and for reduction of the influence of noise. Both for this purpose and for a quantification of the random error it is necessary to characterize the noise, applying theory, random time functions and stochastic processes. Four main types of statistical functions are used to describe the tosic properties of random data ... 

The aids to chromatography include a) resolution calculations on chromatograms of standard mixtures to monitor column performance, b) calculation of Kovats retention index for help in identifying peaks, and (c) multiple point calibration curves for improved quantitation. The file searching routines access two sets of data. Information (such as molecular formula, molecular weight) is stored on 3100 compounds from the Arctander data( ). This allows a quick computer search through the data which is difficult... 

If there is no or little information on the method s performance characteristics, it is recommended that the method s suitability for its intended use in initial experiments be proven. These studies should include the approximate precision, working range, and detection limits. If the preliminary validation data appear to be inappropriate, the method itself, the equipment, the analysis technique, or the acceptance limits should be changed. In this way method development and validation is an iterative process. For example, in liquid chromatography selectivity is achieved through selection of mobile-phase composition. For quantitative measurements the resolution factor between two peaks should be 2.5 or higher. If this value is not achieved, the mobile phase composition needs further optimization. 

In contrast to analytical chromatography, where it is possible to deconvolute overlapping peaks and to obtain even quantitative information from non-resolved peaks,... 

Ion chromatography can be used as a qualitative or quantitative technique. Qualitative information allows a substance to be identified on the basis of retention time comparisons between a standard and the sample ion. When used quantitatively, the IC can employ external or internal standards to generate a standard curve. Then, the peak area of the sample peak on the chromatogram can be used to obtain a concentration. 

In contrast to analytical chromatography, where it is possible to deconvolute overlapping peaks and to obtain even quantitative information from nonresolved peaks, preparative chromatography typically requires complete peak resolution if the components of interest are to be isolated with 100% purity and yield. Chromatographic resolution is a measure of how well two adjacent peak profiles of similar area are separated. is mostly defined as (Equation 2.43)... 

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