Automated on-line ionic detergent removal from minute protein/peptide samples prior to liquid chromatography-electrospray mass spectrometry

An automated online ionic detergent removal pre-column system coupled to capillary liq. chromatog.-electrospray mass spectrometry is described. The system involves two micro precolumns, composed of a specific ionic detergent trapping column and a preconcn. column, resp., and a packed 300 micro m I.D. anal. column. Sample loading to the micro precolumns and regeneration of the detergent trapping column were preformed at a flow-rate of 5.0 micro l/min. while the flow-rate through the anal. column was set at 5.0 micro l/min. Ionic detergent-contg. tryptic-digested protein samples were directly applied to the micro precolumns without sample pretreatment and were analyzed by UV absorption detection and electrospray mass spectrometer. The presented system allows for the fully automated removal of SDS with virtually no loss in protein/peptides. Max. SDS load and breakthrough have been detd. Excellent protein recovery and complete removal of SDS is found. The chromatog. sepn. after SDS removal was completely restored and equaled the ref. chromatogram. Mass spectral data confirm these findings. Finally, this technique allows for SDS removal from minute protein samples without the need for any sample handling. [on SciFinder (R)