Benzimidazole, coumrindione and flavone derivatives as alternate UV laser desorption ionization (LDI) matrices for peptides analysis

BACKGROUND: Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization mass spectrometric technique, allowing the analysis of bio-molecules and other macromolecules. The matrix molecules require certain characteristic features to serve in the laser desorption/ionization mechanism. Therefore, only a limited number of compounds have been identified as ultraviolet- laser desorption/ionization (UV-LDI) matrices. However, many of these routine matrices generate background signals that useful information is often lost in them. We have reported flavones, coumarindione and benzimidazole derivatives as alternate UV-LDI matrices. RESULTS: Thirty one compounds have been successfully employed by us as matrices for the analysis of low molecular weight (LMW) peptides (up to 2000 Da). Two peptides, bradykinin and renin substrate tetra-decapeptide were analyzed by using the newly developed matrices. The MS measurements were made after mixing the matrix solution with analyte by using dried droplet sample preparation procedures. The synthesized matrix materials showed better S/N ratios and minimal background signals for low mass range. Furthermore, pico molar concentrations of [Glu(1)]-fibrinopeptide B human could be easily analyzed with these matrices. Finally, BSA-digest was analyzed and identified through database search against Swiss-Prot by using Mascot. CONCLUSIONS: These results validate the good performance of the synthesized UV-laser desorption/ionization (LDI) matrices for the analysis of low molecular weight peptides.