Laser desorption-Fourier transform mass

Mass Spectrometry. Field desorption mass spectrometry has been used to analy2e PPO (179). Average molecular weight parameters (M and could be determined using either protonated (MH + ) or cation attachment (MNa + ) ions. Good agreement was found between fdms and data supphed by the manufacturer, usually less than 5% difference in all cases up to about 3000 amu. Laser desorption Fourier transform mass spectrometry was used to measure PPG ion and it was claimed that ions up to m/2 9700 (PEG) can be analy2ed by this method (180). 

Brown, R. S. Wilkins, C. L. Laser desorption Fourier transform mass spectrometry of synthetic porphyrins. Anal. Chem. 1986,58,3196-3199. 

The initial observation is that PMMA is essentially completely degraded to monomer by heating to 375°C in a sealed tube while heating a mixture of red phosphorus and PMMA under identical conditions yields a solid, non-deqraded, product as well as a lower yield of monomer. One may observe, by 3C NMR spectroscopy, that the methoxy resonance is greatly decreased in intensity and methyl, methoxy phosphonium ions are observed by 31P NMR. Additional carbonyl resonances are also seen in the carbon spectrum, this correlates with a new carbonyl vibration near 1800 cm 1 in the infrared spectrum and may be assigned to the formation of anhydride. The formation of anhydride was also confirmed by assignment of mass spectra obtained by laser desorption Fourier transform mass spectroscopy, LD-FT-MS. 

C. L. Wilkins, D. A. Weil, C. L. C. Yang, and C. F. Ijames, "High Mass Analysis by Laser Desorption Fourier Transform Mass Spectrometry," Anal. Chem., 57, 520-524 (1980). 

R. E. Hein and R. B. Cody, "Laser Desorption Fourier Transform Mass Spectrometry of Organic Compounds," Presented at the 31st Annual Conference on Mass Spectrometry and Allied Topics, Boston, MA (May 8-13, 1983). 

C. E. Brown, P. Kovacic, C. A. Wilkie, R. B. Cody, R. E. Hein, and J. A. Kinsinger, "Laser Desorption/Fourier Transform Mass Spectral Analysis of Various Conducting Polymers," Synthetic Metals, 15, 265-279 (1986). 

Analytical Applications of Laser Desorption—Fourier Transform Mass Spectrometry for Nonvolatile Molecules... 

Laser desorption Fourier transform mass spectrometry (LD-FTMS) results from a series of peptides and polymers are presented. Successful production of molecular ions of peptides with masses up to 2000 amu is demonstrated. The amount of structurally useful fragmentation diminishes rapidly with increasing mass. Preliminary results of laser photodissociation experiments in an attempt to increase the available structural information are also presented. The synthetic biopolymer poly(phenylalanine) is used as a model for higher molecular weight peptides and produces ions approaching m/z 4000. Current instrument resolution limits are demonstrated utilizing a polyethylene-glycol) polymer, with unit mass resolution obtainable to almost 4000 amu. 

For infrared laser desorption Fourier transform mass spectrometry (LD-FTMS), all den-drimer samples were prepared by dissolving ca. 1 mg of sample in CH2CI2, followed by deposition upon stainless steel probe tips by the aerosol spray technique described previously [37]. Dendrimer samples 4 and 5 were deposited directly onto a stainless steel probe tip. The sample 6 was prepared by first spraying 50 mL of a saturated silver nitrate/ethanol solution (containing ca. 3 mg of silver nitrate) onto the rotating probe tip, prior to dendrimer deposition. Samples were introduced into the vacuum system and the source cell pressure reduced to 2.2 X 10 Torr and the analyzer cell pressure to 2.0 x 10 Torr, before analysis. 

Laser-Desorption Fourier-Transform Mass Spectrometr (LD FTMS) was used by Rice and Weil... 

LD-FTMS Laser Desorption Fourier Transform Mass Spectrometry... 

Nuwaysir, L.M., Wilkins, C.L., and Simonsick, W.J., Analysis of Copolymers by Laser Desorption Fourier Transform Mass Spectrometry, /. Am. Soc. Mass Spec-trom, 1, 66 (1990). 

It is clear that laser desorption Fourier transform mass spectrometry has significant potential as a polymer analysis tool. It works especially well for polar polymers and additives witii molecular weights lower than 10000 Da. AAftth proper attention to analytical details, it is a highly accurate and quite specific way to characterize tiiese substances and can provide unrivaled mass resolution. As is obvious from this chapter, the application of LD-FTMS to polymer analytical problems is an active area of investigation in many laboratories. AAftth the continuing proliferation of commercial FTMS instruments, LD-FTMS applications of polymer analysis should be expected to expand for the foreseeable future. There is no question tiiat tiiis method provides a versatile alternative to tire numerous less specific analytical methods employed to date. 

Brown, C. E., Kovacic, R, Wilkie, C. A., Hein, R. E., Yaniger, S. I., and Cody, R. B. J., "Polynuclear and Halogenated Structures in Polyphenylenes Synthesized from Benzene, Biphenyl, and p-Terphenyl under Various Conditions Characterization by Laser Desorption/Fourier Transform Mass Spectrometry,". Polym. Sci. Polym. Chem, Ed, 24, 255-267,1986. 

Nuwaysir, L. M. and Wilkins, C. L., "Laser Desorption Fourier Transform Mass Spectrometry of Rolymers Comparison with Secondary Ion and Fast Atom Bombardment Mass Sp>ectrometry," Anal. Chem., 60, 279-282, 1988. 

Kahr, M. S. and Wilkins, C. L., "Silver Nitrate Chemical Ionization for Analysis of Hydrocarbon Polymers by Laser Desorption Fourier Transform Mass Spectrometry," /. Am. Soc. Mass Spectrom., 4, 453-460,1993. 

Srzic, D., Martinovic, S., Pasa ToUc, L., Kezele, N., Kazazic, S., Senkovic, L., Shevchenko, S. M., and Klasinc, L., "Laser Desorption Fourier Transform Mass Spectrometry of Natural Polymers," Rapid Commun. Mass Spectrom., 10,580-582, 1996. 

Brown, R.S., Weil, D.A., and Wilkins, G.L., "Laser Desorption Fourier-Transform Mass-Spectrometry for the Gharacterization of Polymers," Macromolecules 19, 1255-1260, 1986. 

Hettich, R. and Buchanan, M. (1991) Structural characterization of normal and modified oligonucleotides by matrix-assisted laser desorption Fourier transform mass spectrometry./. Am. 

Other examples include laser desorption Fourier transform mass spectrometry, where gold was evaporated onto precoated Macor tips [59] infrared reflection spectroscopy (IRS), where gold was evaporated onto Cr coated stainless steel rods [25] and SAW [60-62] experiments, where gold was evaporated onto precoated SAW devices (ST-cut quartz with A1 transducers). 

Coates, M.L. Wilkins, C.L. Laser Desorption Fourier Transform Mass Spectra of Malto-Oligosaccharides. Biomed. Mass Spectrom. 1985,12, 424-428. 

McCrery, D.A. Ledford, E.B., Jr. Gross, M.L. Laser Desorption Fourier Transform Mass Spectrometry. Anal. Chem. 1982,54,1435-1437. 

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