AUTOMATED ONLINE IONIC DETERGENT REMOVAL FROM MINUTE PROTEIN PEPTIDE SAMPLES PRIOR TO LIQUID-CHROMATOGRAPHY ELECTROSPRAY MASS-SPECTROMETRY/

An automated on-line ionic detergent removal pre-column system coupled to capillary liquid chromatography-electrospray mass spectrometry is described. The system involves two micro precolumns, composed of a spe cific ionic detergent trapping column and a preconcentration column, r espectively, and a packed 300 mu m I.D. analytical column. Sample load ing to the micro precolumns and regeneration of the detergent trapping column were performed at a flow-rate of 50 mu l/min, while the flow-r ate through the analytical column was set at 5.0 mu l/min. Ionic deter gent-containing tryptic-digested protein samples were directly applied to the micro precolumns without sample pretreatment and were analysed by UV absorption detection and electrospray mass spectrometry. The pr esented system allows for the fully automated removal of SDS with virt ually no loss in protein/peptides. Maximum SDS load and breakthrough h ave been determined. Excellent protein recovery and complete removal o f SDS is found. The chromatographic separation after SDS removal was c ompletely restored and equalled the reference chromatogram Mass spectr al data confirm these findings. Finally, this technique allows for SDS removal from minute protein samples without the need for any sample h andling.