Fig. 2.

GC-MS analysis of 3C and 4C sugar acids and enantiomers from various meteorites. (A) Racemic glyceric acid (Upper) and 4C acids including a d-excess in threonic acid (Lower) from GRA 95229. (B−D) Analyses from the indicated meteoritic samples: Murch 39 (B), glyceric acid (Upper) and 4C acids (Lower); Murch 38 (C), 4C acids; and ALH 831102 (D), 4C acids; the rare branched compound HMG is ubiquitous (see Results). Erythronic acid also contains a d EE (Table 1). All compounds were analyzed as isopropyl ester/trifluoroacetyl ester (i-Pr/TFA) derivatives (see SI Materials and Methods).