A New Post-Chromatographic Derivatization Approach to the Identification of Alcohols and Phenols in Complex Mixtures by a Combination of Planar Chromatography and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Resumo

A simple and suitable approach to the post-chromatographic derivatization in the analysis of alcohol and phenols mixtures by a combination of thin-layer chromatography and MALDI mass spectrometry was proposed for the first time. The chemical modification of analytes was accomplished by the treatment of eluted zones on thin-layer chromatograms by 3-bromopropionyl chloride in the presence of an excess of a base (pyridine or triethylamine). The resulting derivatives contained a residue with a constant charge (ammonium fragment) that ensures the efficient desorption of the derivatized analytes from the sorbent layer during MALDI. It was shown that the proposed approach allows the recording of mass spectra with a high signal/noise ratio and the detection of alcohols and phenols of different structures. The reproducibility of such MALDI mass spectra is rather high, which predetermines a possibility of building chromatogram curves using total or selected ion current and, hence, their visualization and treatment on the quantitative level.