A NOVEL MU-ESI SOURCE FOR COUPLING CAPILLARY ELECTROPHORESIS AND MASS-SPECTROMETRY - SEQUENCE DETERMINATION OF TUMOR PEPTIDES AT THE ATTOMOLE LEVEL

Membrane preconcentration transient isotachophoresis capillary electro phoresis (mPC-tITP-CE) was coupled to an ion trap mass spectrometer (M S) through a porous glass joint ion electrospray ionization source (mu -ESI source). This novel CE/MS interface gave enhanced signal with les s chemical background while proving to be both durable and easy to man ufacture. The utility of the mPC-tITP-CE/mu-ESI/MS combination for pro viding a separation orthogonal to high-performance liquid chromatograp hy (HPLC) with detection limits compatible with immunological samples was demonstrated using a melanoma tumor cell extract from the DM6 cell line. This system easily resolved the antigen peptide from other cand idate peptides not differentiated after multiple dimensions of HPLC. D etection limits of < 50 amol in full-scan MS and MS/MS modes were obse rved. This system was not concentration limited. 1998 John Wiley & Son s, Inc.