Research for amino acids in lunar samples.

Abstract

Water extracts of lunar fines were analyzed for amino acids by a gas-liquid chromatographic technique whereby amino acids were converted to the N-trifluoroacetyln-butyl, esters prior to analysis. The lunar material studied included both Apollo 14 (14240 SESC and 14298) and Apollo 12 (12023) samples. The water extract of the ‘special’ Apollo 14 sample (14240 SESC) was analyzed both for free and bound amino acids (hydrolysis with 6 N hydrochloric acid). In both the hydrolyzed and unhydrolyzed extracts, the amino acids were not observed above background levels. The analysis of Apollo 12 and 14 samples (12023 14298) yielded similar results. Detection limits were established at 300 pg to 1 ng for different amino acids. A large chromatographic peak with a retention temperature of 126°C was observed on analysis of sample, (12023); it was identified as oxalic acid by GC-MS. The concentration of amino acids in the Apollo 14 SESC samples processed and analyzed in the joint experiments at Ames by GLC and IEC were found to be extremely low (glycine at 3 to 4 ng g−1). As the quantities were so minute, these identifications could not be confirmed by GLC-MS and therefore should still be considered as tentative. Other studies included the analysis of performance standards at the 2 to 6 ng level of each of 17 amino acids, and the analysis of 5 ml of H2O containing 2 ppb of each amino acid. Recovery of amino acids added to lunar fines were conducted at the 10, 50, and 70 ng level of each amino acid with 50 to 70 mg of lunar material. The recoveries varied from as high as 80% for some of the aliphatics to complete loss of the amino acids ornithine and lysine.