Rapid fabrication of functionalized plates for peptides, glycopeptides and protein purification and mass spectrometry analysis†
A rapid and simple approach for fabricating a disposable functionalized membrane on matrix-assisted laser desorption ionization (MALDI) targets, glass, or plastic substrates, without using complex mechanical protocols or chemical reactions, was developed for sample enrichment and mass spectrometry analysis. By coating functionalized-silica particles on a polydimethylsiloxane (PDMS)-coated plate, these particles can form a monolayer of materials on the PDMS membrane for sample handling without peeling off. An octadecyl(C18)-functionalized plate was fabricated by coating porous C18-silica particles on a PDMS-coated plate. The C18 particle-coated PDMS plate (CP plate) has better sensitivity than C18 tips and magnetic nanoparticles, along with a higher sample recovery (64.3 ± 4.9%) compared to the C18 tip method, when analyzing trace amounts of 5 fm BSA digest samples. The CP plate shows significantly higher urea/SDS removal efficiency on the cell lysate proteome compared to C18 tips. The capacity of the C18 spot (∼2.8 mm in diameter) on the CP plate was ∼10 μg of BSA digests. A hydrophilic particle-coated PDMS plate was also fabricated and successfully used for glycopeptide enrichment and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis.