Monolithic thin-layer chromatography plates with covalently bonded matrix for hyphenation with matrix-assisted laser desorption/ionization.

Monolithic layers prepared by the copolymerization of ethylene dimethacrylate and glycidyl methacrylate and deposited onto the surface of glass and silicon plates were investigated as thin-layer chromatography separation media in hyphenated thin-layer chromatography with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Varying composition of the polymerization mixture and polymerization conditions layers of different porosities and MALDI-MS compatibility were synthesized. Compatibility with MALDI-MS was tested using polyethylene glycol and it was demonstrated that layers prepared without glycidyl methacrylate are not compatible with MALDI-MS and do not allow obtaining any mass spectra. Best results were achieved with layers containing 19 to 29% glycidyl methacrylate. These layers allow the measurement of mass spectra without additional depositing matrix compounds supplying mass spectra almost "clean" in low molar mass range.