Before gas-liquid chromatographic (GLC) analysis of the purine and pyrimidine bases, nucleosides, or nucleotides can be accomplished, these compounds must be converted to suitable volatile derivatives. The trimethylsilylation of active hydrogens is overwhelmingly preferred for GLC with nucleic acid components. The trimethylsilyl (TMS) derivatives can be formed using hexamethyldisilazane and trimethylchlorosilane, bis (trimethylsilyl) acetamide, or bis (trimethylsilyl) trifluoroacetamide. Although numerous GLC techniques (1-15) are available for the analysis of silylated nucleic acid components, no particular emphasis has been given to the thin-layer chromatographic (TLC) separation of TMS purines and pyrimidines. Hancock (9) resolved TMS adenosine from adenosine on chromatographic sheets coated with silica gel. He (10) also reported the TLC separation of silylated methyl derivatives of adenosine.
Chromatography is essentially a separation technique and supporting evidence is often required to identify the separated components of the mixture. It would be desirable, however, to obtain more specific data for identification, and in this effort the isolated compounds have been subjected to many forms of spectrometric analysis. Nishimura and Iwai ( 16) reported the UV and IR absorption characteristic of nine isolated TMS bases and nucleosides. Sasaki and Hashizume (1) isolated TMS derivatives of bases and nucleosides and established their structures by elemental analyses and IR and NMR spectroscopy. Hancock (8) studied the UV and IR absorption of silylated nicotinamide-adenine dinucleotide. The chromatographic and spectrometric information of silylated purines and pyrimidines could be helpful in the identification and confirmation of bases, nueleosides, and nucleotides. Unfortunately, the literature is far from complete and such information is not available for the purines '