Factors affecting the quantitation of organic compounds in laser mass spectrometry

Abstract

ever, is that because of its small size, only a very small fraction of the entire eluate is sampled and thus the microvoltammetric electrode is much less sensitive than conventional bulk detectors. Experiments designed to remove this disadvantage are currently being pursued. LITERATURE CITED(1) Knecht, L. A.; Guthrle, E. Myers, M. N.; Schemer, P. D.; W i n g s , J. C. Anal. Chem. 1969, 41, 889-892. (IO) Kirkland, J. J.; Yau, W. W.; Stoklosa, H. J.; Dilks, C. H., Jr. J . Chromatogr. Sci. 1977, 15, 303-316. (11) Foley, J. P.; Dorsey, J. G. Anal. Chem. 1983, 55, 730-737. (12) Dayton, M. A.; Brown, J. C.; Stutts. K. J.; Wlghtman, R. M. Anal. Chem. 1980. 52, 946-950. (13) Wlghtman, R. M.; Wlpf. D. 0. I n Electroenalyticel Chemkhy; Bard, A. Factors aff ectlng the reproduclbilHy of organic laser mass spectrometry have been studied. Laser focus, laser power denslty, sample preparatlon method, and Chemical effects contrlbute significantly to the variabtlity of the mass spectra. Defocuslng the laser enhances production of structurally slgniflcant organlc ions. The yield of organic molecular Ions Is

Laser desorption Fourier-transform ion cyclotron resonance mass spectrometry of polymer additives

“…In the focused position, the quasimolecular ions decreased and fragment ions increased in intensity. Carbon clusters and other noncharacteristic fragment ions reported by others (16) were not observed at the power densities used. In some cases the preferred type of cationization was observed to change from K+ at low power densities to Na+ and H+ at higher power densities.…”

Small molecule analysis by MALDI mass spectrometry

“…Use of the nitrocellulose substrate produced a linear standard curve for bradykinin with a correlation coefficient of 0.991 in the 4-200 pmol range. It is important to note that a similar approach was successfully utilized previously to improve signal intensity and reproducibility for direct LDI [128].…”

Characterization of metal complexes of 1,10-phenanthroline, 2,2′-bipyridine, and their derivatives by fast atom bombardment mass spectrometry

“…For example, the stability constants log k,, log kZ, and log k3 for the formation of Co(phen)'+, ~o (~h e n ) ,~+ , and C~(phen)~'+ are 7.25, 6.70, and 5.95 respectively (22). In both FAB and LMS, oxidized ionic species are observed for complexes having oxidizing anions such as C104-.…”