Attomole level capillary electrophoresis-mass spectrometric protein analysis using 5 .mu.m i.d. capillaries

Abstract

In this correspondence the authors report the use of chemically modified 5-[mu]-i.d. capillaries for CE-MS of proteins. The authors have found that the use of small inner diameter capillaries results in greatly improved sensitivity in CE-ESI/MS, an approximately 25-50-fold improvement, for the detection of attomole quantities of injected protein. Previously, Moseley et al. have demonstrated femtomole level detection for peptide separation using approximately 15-[mu]m-i.d. capillaries where a continuous-flow fast atom bombardment interface was utilized, but the choice of capillary i.d. was largely dictated by their interface design, no particular sensitivity advantage related to capillary i.d. was suggested, and the ionization method used is inappropriate for proteins. To the authors knowledge this report demonstrates the first attomole range CE-MS results for proteins and, in particular, the first obtained with scanning MS detection. 19 refs., 2 figs.