Mass spectrometry plasma desorption

The transuranium element californium was first observed in the 60-inch cyclotron at Berkeley in 1950, where bombardment of Cm with 35-MeV helium ions produced Heavier isotopes of this dement are produced by intense neutron 

The technique introduced by the Macfarlane group was originally referred to as Coulomb ionization since the process of excitation was similar to the Coulomb excitation of nuclei by fast heavy ions. The term fission-fragment induced desorption (FFID) was used by Field and ChaiC to describe the technique without implying a particular mechanism. Other investigators, including Bo Sundqvist at the Tandem 

FIGURE 4.1 The first Cf-PD mass spectrum recorded on February 9, 1973, using a time-to-amplitude converter and pulse-height analyzer. 

Molecular biologists, biochemists, and immunologists were envisioned as the major user groups for this technique. However, with the exception of a californium-based instrument constructed at the Rockefeller Institute and an instrument at the National Institutes of Health (constructed by the Texas A M laboratory), PDMS was carried out primarily in nuclear physics laboratories for nearly 10 years. It was not until 1984 that commercial instruments utilizing Cf sources became available from BIO-ION Nordic (Uppsala, Sweden). Their first instrument, the BIN-lOK, was installed in laboratories at Odense University (Sweden), The Johns Hopkins University (Baltimore, MD), and the Mayo Clinic (Rochester, MN). A later model, the BIO-ION 20, reached worldwide sales of more than 50 instruments by 1993, when BIO-ION announced that it would no longer manufacture plasma desorption instruments. 

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Tuszynski, W. et al.. The observation of chlorophyll a aggregates with plasma desorption mass spectrometry, in Proceedings of the 5th International Conference of Ion Formation from Organic Solids (IFOS V), Hedin, A., Sundqvist, B.U.R. and Ben-ninghoven. A., Eds., Wiley, Chichester, England, 1989. 

G. Jonsson, A. Hedin, P. Hakansson, B. U. R. Sundqvist, H. Bennich, and P. Roepstorff. Compensation for Non-Normal Ejection of Large Molecular Ions in Plasma-Desorption Mass Spectrometry. Rapid Commun. Mass Spectrom., 3(1989) 190-191. 

B. Sundqvist and R. D. Macfarlane. 252Cf-Plasma Desorption Mass Spectrometry. Mass Spectrom. Rev., 4(1985) 421-460. 

Hunt, J.E., MacFarlane, R.D., Katz, J.J., and Dougherty, R.C. 1981. High-energy fragmentation of chlorophyll a and its fully deuterated analog by 252Cf plasma desorption mass spectrometry. J. Am. Chem. Soc. 103 6775-6778. 

Figure 5-3. Plasma desorption mass spectra of anthocyanidins extracted from A. chrysanthemum, B. begonia, C. carnation, and D. phlox. The data in this figure was published in the article Plasma desorption mass spectrometry of anthocyanidins , Rap. Comm. Mass Spectrom. 7 400-403, by Wood, K. V., Bonham, C. C., Ng, J., Hipskind, J. and Nicholson, R. L. 1993. Copyright John Wiley and Sons. Reproduced with permission.

Sundqvist, B. and Macfarlane, R. D., 19 8 5, 252Cf-plasma desorption mass spectrometry, Mass Spectrom. Rev. 4 421-460. 

Thus as a starting point for understanding the bombardment process we have developed a classical dynamics procedure to model the motion of atomic nuclei. The predictions of the classical model for the observables can be compared to the data from sputtering, spectrometry (SIMS), fast atom bombardment mass spectrometry (FABMS), and plasma desorption mass spectrometry (PDMS) experiments. In the circumstances where there is favorable agreement between the results from the classical model and experimental data It can be concluded that collision cascades are Important. The classical model then can be used to look at the microscopic processes which are not accessible from experiments In order to give us further insight into the ejection mechanisms. 

S. Aduru and B. T. Chait, Cf-252 plasma desorption mass spectrometry of oligosaccharides and glycoconjugates—control of ionization and fragmentation, Anal Chem., 63 (1991) 1621-1625. 

Plasma-desorption mass spectrometry is another technique that has been applied successfully to the detection of readily removable fatty acyl substituents in intact glycolipids and their acylated derivatives. The specific location of the fatty acyl substituents in the ring of the glycosyl residues, as in LOS antigens, is determined by methylation under nonbasic conditions (see Section II.lb), followed successively by O-deacylation, ethylation of the exposed hydroxyl groups, and GC-MS analysis of partially alkylated alditol acetates21 ethyl groups denote the sites of previous O-acylation. 

Plasma-desorption mass spectrometry (PDMS) also allowed location of the acyl functions. Thus, 252Cf-PDMS of LOS V in M. kansasii gave27 molecular-weight-associated ions at mlz 2499. The major acylating function of the intact LOS was determined to be a 2,4-dimethyltetradecanoate. Addition of three of these fatty acyl residues to the oligosaccharide portion gave a mass of 2476 daltons. Thus, the ion at mlz 2499 must be equivalent to [M + Na]+, and therefore LOS V must be a tri-O-acyl-undecasaccharide. However, exact location of the acyl functions was not obtained in this way. 

Karibian, D., Deprun, C., Carofif, M. Use of plasma desorption mass spectrometry in structural analysis of endotoxins effects on lipid A of different acid treatments. Prog Clin Biol Res 392 (1995) 103-111. 

The rarest of these specialized techniques, californium-252 plasma desorption mass spectrometry, has not been applied extensively to inorganic systems, though in a 1983 review (115) Macfarlane quotes several examples, such as polymeric platinum blue, with molecular ions extending to m/z 3000. At present there are only 10 functioning systems and this certainly limits its growth. 

Sheets EB, Rhodes D (1996) Determination of DMSP and other onium compounds in Tetraselmis subcordiformis by plasma desorption mass spectrometry. In Kiene RP, Visscher PT, Keller MD, Kirst GO (eds) Biological and environmental chemistry of DMSP and related sulfonium compounds. Plenum Press, New York, pp 55-63 Sieburth JM (1960) Acrylic acid, an antibiotic principle in Phaeocystis blooms in Antarctic waters. Science 132 676-677... 

Further characterization of the remaining fraction in the low-sulfur keratin group in the ethanol-treated animals included analysis of the trypsin-released peptides by plasma desorption mass spectrometry. These results indicated the... 

Californium-252 time-of-flight plasma desorption mass spectrometry performed on 30 pmol of Hez-PbAN indicated two molecular ion peaks (Figure 4). The first peak at m/z 3934 [(M+ ) ], presumed to be the singly charged molecular ion, and a second broader peak centered at m/z 1966 [(M+2H) ], assumed to be the doubly-charged molecular ion, corresponded to molecular weights of 3933 and 3930, respectively. 

Because C-terminal amides have often been reported in insect neuropeptides (8), a 33 residue C-terminal amide consistent with the sequence data was synthesized by solid-phase methods. The peptide was purified by HPLC and its structure confirmed by automated Edman degradation. Californium-252 time-of-flight plasma desorption mass spectrometry provided additional evidence for the structure via a very broad peak for the singly-charged molecular ion at m/z 3902-3906. Because the calculated MW of Hez-PBAN (3899.6, based on the most abundant ion in the isotope cluster) was seen to differ from that observed in the mass spectrum of the isolated native peptide by ca. 32, it was presumed that the native peptide had undergone oxidation of both its methionines to their respective sulfoxides during the course of its isolation and purification. 

Macfarlane, R.D., Uemura, D., Ueda, K., and Hirata, Y. 1980. Cf plasma desorption mass spectrometry of palytoxin. Journal of the American Chemical Society 102(2) 875-876. 

Figure 3.4 Schematic diagram of the disk interface for coupling LC and plasma-desorption mass spectrometry (from ref 67, 1983, Elsevier Science).

Concentration detection limits in CE-MS with the ESI interface are similar to those with UV detection. Sample sensitivity can be improved by using ion-trapping or time-of-flight (TOE) mass spectrometers. MS analysis can also be performed off-line, after appropriate sample collection, using plasma desorption-mass spectrometry (PD-MS) or matrix-assisted laser desorption-mass spectrometry (MALDI-MS). 

Latest results have been obtained by both Cf plasma desorption and FAB. The former is an ongoing study by Macfarlane on a decanucleotide (molecular mass — 4000) results on the sequence analysis are not yet available. The sequencing of a fully protected oligonucleotide, using 5 - and 3 -exonucleases has been proposed for one heptanucleotide, using Cf-plasma desorption mass spectrometry. For that type of work the negative ion mode was shown to be fast and reliable. 

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