GSD (Global Spectrum Deconvolution) in Metabolomics: Absolute Quantification and GSD Binning

In addition, we have taken advantage of GSD to implement under Mnova the quantitative referencing strategy known as PULCON [5]. It is well known that when dealing with biological samples containing lipids and proteins, one can not use an internal standard to perform absolute quantification of metabolites. This is due to the fact that all possible reference compounds (such as TSP or DSS) interact with large biological molecules, making the quantification error prone. By combining the GSD algorithm with a PULCON script we are able to deconvolute overlapped regions and perform absolute quantification even of metabolites whose peaks are buried under these areas. In order to verify the quality of the quantification, we have acquired spectra of a commercial cell culture medium which is a complex but well known mixture of more than 20 compounds. We then compare the metabolite concentrations obtained from experimental spectra by means of the GSD PULCON algorithm with those declared by the medium vendor.