RESUMEN
RATIONALE: Direct analysis of hydroxyl-containing compounds by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) methods is not always possible due to the neutral character of analytes. The suggested fixed-charge derivatization may increase the ionization efficiency for various alcohols and phenols in specific matrix- and surface-activated LDI conditions. METHODS: Aliphatic and steroid alcohols, as well as chlorophenols, were converted into various ammonioacetyl derivatives, containing a covalently bonded charged group, by reaction with bromoacetyl chloride and amine-type compounds such as triethylamine, pyridine or quinoline. The derivatives are suitable for MALDI-time-of-flight (TOF)MS analysis. RESULTS: Triethylammoniumacetyl, pyridyliumacetyl and quinoliniumacetyl derivatives were prepared from aliphatic alcohols, some sterols and chlorinated phenols in one stage with quantitative yields. The derivatives produced characteristic MALDI and SALDI mass spectra. CONCLUSIONS: The suggested derivatization approach for the modification of alcohols is simple and does not require any expensive reagents. The derivatives include a fixed charge and produce intense signals in MALDI (preferentially non-acidic matrices) and matrix-free SALDI (nanostructured target) conditions. Corresponding mass spectra are suitable for the determination of molecular mass and profiling of alcohols.
