Chromatographic Deconvolution

Chromatographic Deconvolution

Data from analytical instruments needs to be processed before it can be analysed and interpreted. The key feature in AnalyzerPro is its ability to chromatographically deconvolute data. Deconvolution is defined as ‘reversing the effects of convolution’. For chromatographic data the biggest problem is co-elution of chromatographic peaks as many components will not be completely separated by the column. Using AnalyzerPro we can determine which masses belong to which of the co-eluting peaks. The deconvolution step also allows the creation of target component lists. For comprehensive data analysis, automated library building is available in AnalyzerPro which includes all the components within an entire data set. This differs from a traditional target component list generated from standards in that the components do not need to be identified until later in the analysis. However, the traditional approach is also available in AnalyzerPro.

For example, a metabolomic study was conducted on the kidney tissue of a rat model for polycystic kidney disease. AnalyzerPro processed the data and library searched the found components against an in-house target component library of authentic metabolite standards. Components were also searched against the NIST mass spectral database for tentative identification of the unknowns. Tryptophan, the deconvoluted peak at the retention time 35.45 minutes with a base peak of m/z 202 was only found in the polycystic kidney tissue and not the healthy age-matched and sex-matched control animal kidney tissue. As with many metabolomic studies, there may be several interpretations of this finding which in turn may generate new hypotheses to test.

As shown below, AnalyzerPro is able to automatically determine component 505 (tryptophan) in the disease state samples in the presence of high levels of Docosane (a hydrocarbon added for RI calculation).

AnalyzerPro automatically determining tryptophan in high leves of docosane.

Figure 1. AnalyzerPro automatically determine tryptophan in high levels of docosane.

In each case, high quality library searchable spectra were obtained for each component with no prior knowledge of the sample. The following shows the extracted ion chromatograms for each of the masses of the components and their corresponding spectrum.

Spectrum and EICs of docosane

Figure 2. Spectrum and EICs of docosane [Component 504]

Spectrum and EICs of tryptophan

Figure 3. Spectrum and EICs of tryptophan [Component 505]

In this way, AnalyzerPro is able to generate library searchable spectra for closely eluting components.