Fig. 4.

Nitrogen allows aldehyde retention at room temperature in simulated precometary organic residues. (A) Identification of glycolaldehyde (1a, b), lactaldehyde (2a, b), and (E)-glyceraldehyde (3) as O-pentafluorobenzyl oxime-trimethylsilylether derivatives from a VUV-irradiated ice mixture containing ammonia. Double peaks occur because two isomers are formed. (B) Complex aldehydes are absent in samples without ammonia in the initial ice mixture. Peaks marked with an asterisk are interferences caused by the derivatization protocol revealed by running (C) a blank sample of the derivatization reagents.