PREPARATION OF TRIMETHYLSILYL DERIVATIVES OF NUCLEIC-ACID COMPONENTS FOR ANALYSIS BY MASS-SPECTROMETRY

This chapter discusses preparation of trimethylsilyl derivatives of nucleic acid components for analysis by mass spectrometry. Analysis of nucleic acid bases, nucleosides, and nucleotides by electron ionization (EI) or chemical ionization (CI) mass spectrometry is best performed following conversion to their trimethylsilyl (TMS) derviatives. In terms of gas chromatography-mass spectrometry (GC/MS) characteristics, and relative to other derivatives, the TMS analogs (1) provide good gas chromatographic peak shape with reproducible retention times and narrow solvent peaks, (2) afford a wealth of structural information, with the fragmentation of the TMS derivatives of bases, nucleosides, and nucleotides being, in general, well understood. Reagents are also commercially available for the preparation of the deuterium-labeled TMS derivative, the mass spectrum of which can be used to confirm tentative ion structures assigned on the basis of the spectrum of the unlabeled TMS analog. The degree of success that may be expected from the GC/MS separation and analysis of nucleic acid components depends on the complexity and polarity of the compound(s) being examined. © 1990, Elsevier Inc. All rights reserved.