title: The 13C/12C ratio in black pulmonary pigment: a mass spectrometric study.
abstract: Ratios of the two stable isotopes of carbon, 13C and 12C, were measured in black pulmonary pigment and in several endogenous tissues removed during 20 autopsies on Long Island, New York. The mass spectrometer used for carbon isotope ratio analyses has a precision of +/- 1 13C atom per million carbon atoms. The 13C/12C ratio was found to be distinctly lower in black pulmonary pigment than in endogenous tissues, the mean difference amounting to 65 13C atoms per million carbon atoms. The results demonstrate that the elemental carbon fraction of black pulmonary pigment is exogenous and constitutes roughly 30 per cent of the weight of the pigmented material. It was also observed that 13C/12C ratios in endogenous tissues from individual autopsy cases were not quite identical, tending to be slightly greater in corpus callosum than in liver or peripheral lung.
mesh_terms: D000368:Aged; D001980:Bronchi / Q000032:analysis; D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis*; D003337:Corpus Callosum / Q000032:analysis; D005260:Female; D006801:Humans; D008099:Liver / Q000032:analysis; D008168:Lung / Q000032:analysis*; D008198:Lymph Nodes / Q000032:analysis; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008482:Mediastinum; D008875:Middle Aged; D009518:New York; D010860:Pigments, Biological / Q000032:analysis*; D011650:Pulmonary Alveoli / Q000032:analysis
chemical_list: D002247:Carbon Isotopes; D010860:Pigments, Biological; D002244:Carbon