Anal. Chem. 1997, 69, 327-332
A New Strategy for MALDI on Magnetic Sector Mass Spectrometers with Point Detectors V. S. Kumar Kolli and Ron Orlando*
Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, 220 Riverbend Road, Athens, Georgia 30602-4712
We have developed a new strategy to perform matrixassisted laser desorption/ionization (MALDI) on magnetic sector instruments equipped with nonintegrating point detectors. This approach is based on using liquid matrices to provide very long-lasting analyte ion currents and to overcome the inability of these instruments to simultaneously detect ions over a range of mass-to-charge values. Here, we demonstrate some of the capabilities of MALDI on a magnetic sector for analyzing biological samples. These capabilities include the ability to perform MS/MS experiments, to attain resolutions over 8000 (full width at half-maximum), and to determine relative molecular masses with 80 000 laser shots) and a laser energy of ∼10 µJ/pulse.12 For example, the low-resolution, MS/MS, and high-resolution spectra of renin substrate discussed above required a total analysis time of only ∼40 min. This suggests that all three of these experiments could have been performed on the same sample. To test this ability, we acquired low-resolution, MS/MS, and multiple high-resolution experiments from the same 10 pmol loading of renin substrate. These spectra were virtually identical to the ones shown above and thus are not shown to avoid redundancy. Consequently, one can perform multiple MALDI magnetic sector experiments on the same sample loading, as is typically done by MALDI on a TOF instrument. ACKNOWLEDGMENT This work was supported by a grant from the National Institutes of Health (NIH Grant No. 2-P41-RR05351-06). The authors thank Ms. Julia Crane for providing the N-linked glycoprotein glycan and Mr. Dennis Warrenfeltz for his technical assistance. Received for review October 9, 1996. Accepted November 26, 1996.X AC961033T X
Abstract published in Advance ACS Abstracts, January 1, 1997.
