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A sublimation technique was developed to isolate purines and pyrimidines directly from 2-deoxyribonucleic acid ([lambda]-DNA) and Escherichia coli cells. The sublimation of adenine, cytosine, guanine, and thymine from [lambda]-DNA was tested under reduced pressure (~ 0.5 Torr) at temperatares of > 150[degrees]C. With the exception of guanine, approximately 60-75% of each base was sublimed directly from the [lambda]-DNA and recovered on a coldfinger of the sublimation apparatus after heating to 450[degrees]C. Several nucleobases including adenine, cytosine, thymine, and uracil were also recovered from E. coli bacteria after heating the cells to the same temperature, although some thermal decomposition of the bases also occurred. These results demonstrate the feasibility of using sublimation to isolate purines and pyrimidines from native E. coli DNA and RNA without any chemical treatment of the cells.

Chiral separations of fluorescein isothiocyanate-labeled amino acids have been performed on a microfabricated capillary electrophoresis chip to explore the feasibility of using such devices to analyze for extinct or extant life signs in extraterrestrial environments. The test system consists of a folded electrophoresis channel (19.0 cm long x 150 [[micro]meter] wide x 20 [[micro]meter] deep) that was photolithographically fabricated in a 10-cm-diameter glass wafer sandwich, coupled to a laser-excited confocal fluorescence detection apparatus providing subattomole sensitivity. Using a sodium dodecyl sulfate/[Gamma]-cyclodextrin pH 10.0 carbonate electrophoresis buffer and a separation voltage of 550 V/cm at 10 [degrees] C, baseline resolution was observed for Val, Ala, Glu, and Asp enantiomers and Gly in only 4 min. Enantiomeric ratios were determined for amino acids extracted from the Murchison meteorite, and these values closely matched values determined by HPLC. These results demonstrate the feasibility of using microfabricated lab-on-a-chip systems to analyze extraterrestrial samples for amino acids.

Amino acids have appreciable vapor pressures above 150 [degrees] C and will sublime under partial vacuum at elevated temperatures without any racemization or decomposition. The recoveries of several amino acids including aspartic acid, serine, glycine, alanine, [Alpha]-aminoisobutyric acid, and valine were optimized by varying the temperature and duration of sublimation. Sublimation has been shown to be a rapid and effective technique for the isolation of amino acids from natural samples for enantiomeric analyses and a good substitute for conventional cation-exchange desalting techniques.