Application of on-line HPLC-FAB mass spectrometry to the analysis of enzymatic digests of ribonuclease B

A tryptic digest of bovine ribonuclease B was analysed by on-line HPLC-FAB mass spectrometry to verify the primary sequence. Peptides obtained by digestion with trypsin before and after treatment with N-glycanase were separated on a slurry-packed fused silica LC column. The entire eluent was introduced into the mass spectrometer source via a continuous flow interface. A single injection of 100 pinoles of material provided data covering over 70% of the sequence.