Laser Ionization Mass Spectrometr

Laser based mass spectrometric methods, such as laser ionization (LIMS) and laser ablation in combination with inductively coupled plasma mass spectrometry (LA-ICP-MS) are powerful analytical techniques for survey analysis of solid substances. To realize the analytical performances methods for the direct trace analysis of synthetic and natural crystals modification of a traditional analytical technique was necessary and suitable standard reference materials (SRM) were required. Recent developments allowed extending the range of analytical applications of LIMS and LA-ICP-MS will be presented and discussed. For example ... 

Bemdt, P., Hobohm, U., and Langen, H. (1999). Reliable automatic protein identification from matrix-assisted laser desorption/ionization mass spectrometric peptide fingerprints. Electrophoresis 20, 3521-3526. 

Krishnamurthy, T. Ross, P. L. Rapid identification of bacteria by direct matrix-assisted laser desorption/ionization mass spectrometric analysis of whole cells. Rapid Commun. Mass Spectrom. 1996,10,1992-1996. 

Lapolla A, Ragazzi E, Andretta B, et al. Multivariate analysis of matrix-assisted laser desorption/ionization mass spectrometric data related to glycoxidation products of human globins in nephropathic patients. J. Am. Soc. Mass. Spectrom. 2007 18 1018-1023. 

Brancia, F.L., Oliver, S.G., and Gaskell, S.J. (2000) Improved matrix-assisted laser desorption/ionization mass spectrometric analysis of tryptic hydrolysates of proteins following guanidination of lysine-containing peptides. Rapid Comm. Mass Spectrom. 14, 2070-2073. 

T. Krishnamurthy and P. L. Ross. Rapid Identification of Bacteria by Direct Matrix-aAssisted Laser Desorption/Ionization Mass Spectrometric Analysis of Whole Cells. Rapid Commun. Mass Spectrom., 10(1996) 1992-1996. 

Site has good software subdivision devoted to matrix-assisted laser desorption/ ionization mass spectrometric imaging (MALDI-MSI, also termed imaging MS or MS imaging). 

Keki, S. et al., Post-source decay matrix-assisted laser desorption/ionization mass spectrometric study of peracetylated isoflavone glycosides cationized by protonation and with various metal ions, J. Mass Spectrom., 38, 1207, 2003. 

Laremore, T. N. et al.. Matrix-assisted laser desorption/ionization mass spectrometric analysis of uncomplexed highly sulfated oligosaccharides using ionic liquid matrices. Anal. Chem., 78,1774,2006. 

In contrast, the LA-ICP-MS (in comparison to laser ionization mass spectrometry (LIMS) where the ion source operates under high vacuum conditions) at present, in spite of the disadvantage of a higher polyatomic ion formation rate, uses an argon plasma ionization at normal pressure - a promising inorganic mass spectrometric technique for trace, isotope and surface analysis which will... 

Several formal and informal intercomparisons of nitric acid measurement techniques have been carried out (43-46) these intercomparisons involve a multitude of techniques. The in situ measurement of this species has proven difficult because it very rapidly absorbs on any inlet surfaces and because it is involved in reversible solid-vapor equilibria with aerosol nitrate species. These equilibria can be disturbed by the sampling process these disturbances lead to negative or positive errors in the determination of the ambient vapor-phase concentration. The intercomparisons found differences of the order of a factor of 2 generally, and up to at least a factor of 5 at levels below 0.2 ppbv. These studies clearly indicate that the intercompared techniques do not allow the unequivocal determination of nitric acid in the atmosphere. A laser-photolysis, fragment-fluorescence method (47) and an active chemical ionization, mass spectrometric technique (48) were recently reported for this species. These approaches may provide more definite specificity for HN03. Challenges clearly remain in the measurement of this species. 

MM Siegel, U Hollander, PR Hamann, JP James, L Hinman, BJ Smith, APH Farnsworth, A Phipps, DJ King, M Karas, A Ingendoh, F Hillenkamp. Matrix-assisted UV-laser desorption/ionization mass spectrometric analysis of monoclonal antibodies for the determination of carbohydrate, conjugated chelator, and conjugated drug content. Anal Chem 63 2470, 1991. 

J. Gnitard, X. L. Hronowskiy, and C. E. Costello, Direct matrix-assisted laser des-orption/ionization mass spectrometric analysis of glycosphingolipids on thin layer chromatographic plates and transfer membranes, Rapid Commun. Mass Spectrom. 13, 1838-1849 (1999). 

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