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Membrane-Free Electrokinetic Device Integrated to Electrospray-Ionization Mass Spectrometry for the Simultaneous Removal of Sodium Dodecyl Sulfate and Enrichment of Peptides

Tubaon, Ria Marni, Haddad, Paul R., Quirino, Joselito P.
Analytical chemistry 2018 v.90 no.17 pp. 10122-10127
bovine serum albumin, bradykinin, capillary electrophoresis, electric field, electrospray ionization mass spectrometry, micelles, proteomics, sodium dodecyl sulfate
The removal of sodium dodecyl sulfate (SDS) in SDS-assisted proteomics with electrospray-ionization-mass-spectrometric (ESI-MS) analysis is an essential step in the analysis. Off-line state-of-the-art sample-preparation strategies can allow 100% removal of DS– and up to 100% peptide recoveries. These strategies, however, are typically laborious and require long analysis times and a complex experimental setup. Here, we developed a simple, membrane-free, electrokinetic, on-line, integrated SDS removal–ESI-MS device that was able to enhance ESI-MS signals of bradykinin and peptides from trypsin-digested bovine serum albumin (BSA) in samples that contained SDS micelles. The significant peptide-signal improvements were contributed by the complete removal of DS– and the enrichment of the peptides in the presence of an electric field. Enrichment was via micelle-to-solvent stacking, initially developed in capillary electrophoresis. Bradykinin percent recovery was 800%, and BSA peptide percent recovery was 87%. Enhancement factors in ESI-MS signals (after and before removal) for selected m/z values of peptides from the BSA digest were 535–693.