THE UNEXTRACTABLE ORGANIC FRACTION OF THE PUEBLITO DE ALLENDE METEORITE: EVIDENCE FOR ITS INDIGENOUS NATURE*
AUTOR(ES)
Simmonds, P. G.
RESUMO
The Pueblito de Allende meteorite contains only 0.1-0.5 ppm of solvent-extractable carbon, most or all of which is due to terrestrial contamination. Determinations of the total carbon content gives values from 0.23 to 0.35 per cent. The presumed indigenous insoluble carbon is thus present in a ratio of 2300:1 relative to contaminant carbon. A sample of the meteorite was extracted with a deuterated solvent containing benzene:methanol (4:1 w/w) to remove contaminants and then was subjected to pyrolysis-gas chromatography-mass spectrometry to investigate the nature of the remaining carbon. The pyrolysis products (about 20 ppm) consisted chiefly of aromatic and substituted aromatic hydrocarbons. The pyrolysis results were confirmed by oxidative thermal analysis which showed that the bulk of the carbon present was a macromolecular structure and not graphite. This suggests that an insoluble nongraphitic condensed aromatic polymer is indigenous to the meteorite. The origin and precise chemical structure of this material has not been determined, but it bears a superficial resemblance to coal-like structures.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=223339Documentos Relacionados
- Allende meteorite: Isotopically anomalous xenon is accompanied by normal osmium
- THE LAMINA CRIBROSA AND ITS NATURE*
- The Buritizal meteorite: classification of a new Brazilian chondrite
- PHOSPHOLIPID MEMBRANE MODEL: IMPORTANCE OF PHOSPHATIDYLSERINE AND ITS CATION EXCHANGER NATURE*
- CHARACTERIZATION OF CYTOPLASMIC AND CHLOROPLAST POLYSOMES IN PLANTS: EVIDENCE FOR THREE CLASSES OF RIBOSOMAL RNA IN NATURE*