Ion trap mass spectrometry as detector for capillary electrochromatography of peptides: Possibilities and limitations

Capillary electrochromatography has been coupled to an ion trap mass spectrometer via a sheath flow electrospray interface. Peptide analysis was performed on 25 cm columns packed with C18‐bonded silica particles, and very fast separations were obtained. Full mass spectrometry and tandem mass spectrometry (MS/MS) detection were evaluated in terms of sensitivity and scanning speed. The separation of seven selected peptides and their detection by MS/MS in selected reaction monitoring mode was demonstrated. The performance of this sheath flow interface also was compared with the previously reported sheathless interface. Despite the loss in sensitivity (20–40‐fold), the sheath flow interface was shown to be superior in terms of ruggedness, and allowed the use of higher electric fields to achieve faster analysis times.