Polymer amide as a carrier of 15N in Allende and Acfer 086 meteorites

Abstract

Polymers of amino acids have been found in Allende and Acfer 086, with extra-terrestrial origin evidenced by isotopically enhanced satellite peaks in the 800-1200 Dalton mass range. The present work employs focused ion beam milling of micron scale powder to generate negative ion spectra containing CN ions at masses 26 and 27 for 15N determination. Respectively, for CN ions, Allende and Acfer 086 show delta 15N = 410 +/- 220 per mil and 1,015 +/- 220 per mil in the powder samples. We measure an exact 1:2 ratio of C2 to CN negative ions that is consistent with ion beam fragmentation of a polymer amide -CCN- backbone into diatomic fragments. It is inferred that polymer amide comprises a large part of the 15N bearing organic material in this CV3 meteorite class.