Surfactants usable for electrospray ionization mass spectrometry

Surfactants suppress the electrospray ionization (ESI) of various compounds . Here we demonstrate that fluorinated surfactants such as perfluorooctanoi c acid (PFOA) and perfluorooctanesulfonic acid (PFOSA) could be employed fo r ESI-MS without a significant decrease in sensitivity. Both PFOA and PFOSA could be applied to the analysis of ionic and nonionic compounds by micell ar electrokinetic chromatography (MEKC)/ESI-MS, although the migration wind ow was limited. Furthermore, in HPLC/ESI-MS, PFOA could function as a paire d ion for enzymatically digested peptides as well as sulfonamides and signi ficant effects of PFOA on the signal peak shape, retention times, and sensi tivity of the analytes were observed compared to those of trifluoroacetic a cid or sodium dodecyl sulfate (SDS). In addition, PFOA was applied to prote in analysis by ESI-MS, and superior sensitivity was noted, compared to othe r surfactants such as octylglucoside, dodecylglucoside, and SDS. Although 2 1% of the original signal was observed in the presence of 1% PFOA, this sur factant could be easily removed by evaporation, which resulted in the recov ery of 96% of the original signal. Because these fluorinated surfactants co uld also be used for solubilization, extraction, and disaggregation of prot eins, they should greatly expand the applicability of the ESI-MS to the bio logical problems of proteins. (C) 2000 Academic Press.