Alteration in amino acid composition of natural solid bitumens and some synthesized carbonaceous materials in the carbonization sequence

Amino acids are important records of geochemical processes in sedimentary rocks. The knowledge about changing the composition of amino acids is important for our understanding of genetics of organic compounds in the geological records. In the presented work, compositions of amino acids in natural solid bitumens, graphites and some synthesized carbonaceous materials were investigated. We determined that the content of amino acids decreases with increasing temperature of the formation of natural carbonaceous substances. the content of aliphatic amino acids gradually increases with increasing degree of transformation in the carbonization (dehydrogenation) series, mainly due to glycine, alanine and leucine. The revealed changes in the amino acid composition of natural carbonaceous substances are associated with the genesis of the initial organic matter, as with as the content of carbonaceous matter and its interaction with the mineral component. We showed that the selection of dominant individual amino acids without involvement of statistical methods did not allow distinguishing some types of natural carbonaceous materials. At the same time, lots of amino acids were identified by statistical methods, statistically significantly distinguishing all the studied types of solid natural bitumen and graphite.