Klf. Brinton et Jl. Bada, A REEXAMINATION OF AMINO-ACIDS IN LUNAR SOILS - IMPLICATIONS FOR THE SURVIVAL OF EXOGENOUS ORGANIC MATERIAL DURING IMPACT DELIVERY, Geochimica et cosmochimica acta, 60(2), 1996, pp. 349-354
Using a sensitive high performance liquid chromatography technique, we
have analyzed both the hot water extract and the acid hydrolyzed hot
water extract of lunar soil collected during the Apollo 17 mission. Bo
th free amino acids and those derived from acid labile precursors are
present at a level of roughly 15 ppb. Based on the D/L amino acid rati
os, the free alanine and aspartic acid observed in the hot water extra
ct can be entirely attributed to terrestrial biogenic contamination. H
owever, in the acid labile fraction, precursors which yield amino acid
s are apparently present in the lunar soil. The amino acid distributio
n suggests that the precursor is probably solar wind implanted HCN. We
have evaluated our results with regard to the meteoritic input of int
act organic compounds to the moon based on an upper limit of less than
or equal to 0.3 ppb for alpha-aminoisobutyric acid, a non-protein ami
no acid which does not generally occur in terrestrial organisms and wh
ich is not a major amino acid produced from HCN, but which is a predom
inant amino acid in many carbonaceous chondrites. We find that the sur
vival of exogenous organic compounds during lunar impact is less than
or equal to 0.8%. This result represents an example of minimum organic
impact survivability. This is an important first step toward a better
understanding of similar processes on Earth and on Mars, and their po
ssible contribution to the budget of prebiotic organic compounds on th
e primitive Earth.