Discriminant analysis of amino acid composition of natural carbonaceous substances

We conducted statistical estimation of difference in amino acid composition of natural carbonaceous materials, previously divided on the basis of physical and chemical features into groups according to Uspensky classification, by discriminant analysis. The samples of natural solid bitumens from a carbonization sequence (asphaltites - kerites - anthraxolites), natural graphites, and carbon black samples were used as objects of the research. It was shown that the samples within each group had similar amino acid composition and the correctness of an initial distribution of the samples into groups was confirmed. In addition, we found individual samples, which had been incorrectly classified as a result of inaccurate physical-chemical diagnostics, and also slightly different from the samples of their group by the geological and geochemical characteristics. This indicates possibility of using discriminant analysis for the comparative grouping of natural carbonaceous substances by amino acid composition.