ANALYSIS OF TRYPTIC DIGESTS USING MICROBORE HPLC WITH AN ION-TRAP STORAGE REFLECTRON TIME-OF-FLIGHT DETECTOR/

An electrospray ionization source interfaced to an ion trap storage/re flectron time-of-flight mass spectrometer is evaluated as a rapid, sen sitive detector for microbore HPLC. Using the total ion storage capabi lities of the trap over a broad mass range, total ion chromatograms of tryptic digests of bovine cytochrome c and bovine beta-casein are obt ained following microbore HPLC separations with samples in the low pic omole range. The digests are analyzed with the aid of software develop ed in our laboratory, which can display the selected ion chromatogram (SIC) for each chromatographic peak. The SIC mode can be used for enha ncement of the S/N and for identification of a chromatographic peak wi th a particular mass. In addition, the mass spectrum corresponding to each chromatographic peak can be displayed to check for unresolved chr omatographic components.