Tetrapyrrole Pigments

Abstract

Both major classes of tetrapyrrole pigments, chlornis and porphyrins, have been found in sediments; chlorins associated with recent sediments and porphyrins with ancient sediments and bitumens (Hodgson et al, 1967; and Baker, 1969). Firm structural identification of the components of these complex mixtures has not been possible because of similarity of spectral and chromamographic properties of homologues. Mass spectrometry has proved to be the most powerful analytical method in unraveling the structures of porphyrins in bitumens (Baker et al, 1967) and its application to the pigments in recent sediments seems a normal extension. A library of mass spectra must be accumulated so that the spectra may be interpreted, and until the present only a scattered few mass spectra of the types expected in sediments have been reported (Jackson et al, 1965). Neither chlorophyll nor the phytol esters of chlorin derivatives have been reported, probably because of their thermal instability. The author has found that readable mass spectra of such compounds can be obtained, and reports preliminary spectra on model compounds and pigments extracted from deep ocean sediments.