ANALYSIS OF PEPTIDE AND PROTEIN SAMPLES CONTAINING SURFACTANTS BY MALDI-MS

Protein samples containing ionic surfactants such as sodium dodecyl su lfate (SDS) can be analyzed by matrix-assisted laser desorption/ioniza tion mass spectrometry, contrary to what is currently accepted, SDS at varying concentrations was added to four polypeptide samples, As expe cted, a decrease in the signal was observed for increasing concentrati ons of SDS up to 0.1% (w/v), at which no signal was observed for three of the analytes. However, a recovery of the signals of all the analyt es was observed at concentrations of SDS above 0.3%, with useful spect ra at concentrations as high as 10%. The SDS concentration at which si gnal recovery starts is always the same, regardless of the type and th e concentration of the analyte. Another two surfactants holamidopropyl )dimethylammonio]-1-propanesulfonate (CHAPS) and octylphenolpoly(ethyl ene glycol ether) 10 (Triton X-100) were also tested, The trend for si gnal variation with CHAPS addition is similar to that for SDS addition , but for Triton X-100, the signal always diminishes with increasing s urfactant concentration, For protein samples containing surfactants wi th anionic groups, addition of more surfactant allows the acquisition of useful mass spectrometric data.