A one-way hydrophobic surface foil as sample support for MALDI and off-line CZE/MALDI mass spectrometry: An alternative for low and high molecular mass compounds

A one-way multilayered flexible hydrophobic foil, fixed onto a standard microtiter-format MALDI target, has been utilized as a sample support for UV matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric experiments as well as for the automated off-line coupling of capillary zone electrophoresis (CZE) with MALDI. Various matrices as well as preparation techniques on this polar solution-repellent foil were evaluated with regard to matrix suppression effects, sensitivity and crystallization of deposited samples as well as drop migration on the surface. The results were compared with those yielded on the conventional stainless steel targets. It turned out that this foil is a sample support of choice due to significant improvements in chemical noise reduction, spot area reduction, sensitivity and no drop migration dealing with low molecular mass compounds such as tryptic peptide mixtures, small organic synthetic biomolecules (200-700 Da) as well as intact proteins. Furthermore the foil was a useful MALDI sample surface for the deposition of CZE peptide fractions in proteomics applications.