Sample preparation matrix assisted laser

Vaidyanathan, S. Winder, C. L. Wade, S. C. Kell, D. B. Goodacre, R. Sample preparation in matrix-assisted laser desorption/ionization mass spectrometry of whole bacterial cells and the detection of high mass (>20kDa) proteins. Rapid Comm. Mass Spectrom. 2002,16,1276-1286. 

Smole, S. C. King, L. A. Leopold, P. E. Arbeit, R. D. Sample preparation of Grampositive bacteria for identification by matrix assisted laser desorption/ionization time-of-flight. J. Microbiol. Meth. 2002, 48,107-115. 

Experimental considerations Sample preparation and data evaluation are similar to membrane osmometry. Since there is no lower cut-off as in membrane osmometry, the method is very sensitive to low molar mass impurities like residual solvent and monomers. As a consequence, the method is more suitable for oligomers and short polymers with molar masses up to (M)n 50kg/mol. Today, vapour pressure osmometry faces strong competition from mass spectrometry techniques such as matrix-assisted laser desorption ionisation mass spectrometry (MALDI-MS) [20,21]. Nevertheless, vapour pressure osmometry still has advantages in cases where fragmentation issues or molar mass-dependent desorption and ionization probabilities come into play. 

Schwartz S, Reyzer M, Caprioli R. Direct tissue analysis using matrix-assisted laser desorption/ionization mass spectrometry practical aspects of sample preparation. /. Mass. Spectrom. 2003 38 699-708. 

Figure 2.9. Schematic of a matrix-assisted laser desorption/ionization (MALDI) event. The SEM micrograph depicts sinapinic acid-equine myoglobin crystal from a sample prepared according to the dried drop sample preparation method. In the desorption event neutral matrix molecules (M), positive matrix ions (M+), negative matrix ions (M-), neutral analyte molecules (N), positive analyte ions (+), and negative analyte ions (-) are created and/or transferred to the gas phase. Reprinted from A. Westman-Brinkmalm and G. Brinkmalm (2002). In Mass Spectrometry and Hyphenated Techniques in Neuropeptide Research, J. Silberring and R. Ekman (eds.) New York John Wiley Sons, 47-105. With permission of John Wiley Sons, Inc.

J. Axelsson, A.-M. Hoberg, C. Waterson, P. Myatt, G. L. Shield, J. Varney, D. M. Haddleton, and P. J. Derrick. Improved Reproducibility and Increased Signal Intensity in Matrix-Assisted Laser Desorption/Ionization as a Result of Electrospray Sample Preparation. Rapid Commun. Mass Spectrom., 11(1997) 209-213. 

Matrix assisted laser desorption ionization time-of-flight (MALDI-TOE) mass spectrometry was carried out with a PerSeptive Biosystems Voyager-DE-RP MALDl-TOF mass spectrometer. A 337-nm UV nitrogen laser producing 3-ns pulses was used in the reflectron mode. The samples were prepared by mixing 10 pi of a 0.1 M HAc solution of the sample with 20 pi of a solution of 3 mg/1 a-cyano-4-hydroxy cinnamic acid in wafer. One pi of that solution was loaded on the gold-sample plate. 

The 1 1 mixtures of strands 19 and 20 (0.5 mM each) were prepared in CH2CI2, methanol, and water. The samples were subjected to redox conditions (I2) for various lengths of time and then examined by matrix assisted laser desorption ionization (MALDI). As expected, 19 and 20 sequence specifically associated with each other in CH2CI2, leading to the disulfide cross-linked 19-20 as the major product. With an increasing ratio of methanol in CH2CI2, the cross-linked 19-20 stUl appeared as the dominant product. The same phenomenon was observed in pure methanol and even in water (Fig. 9.14b). The sequence dependence of the cross-linking of 19 and... 

Nicola, A. J. et al.. Application of the fast-evaporation sample preparation method for improving quantification of angiotensin II by matrix-assisted laser desorption/ionization. Rapid Commun. Mass Spec., 9, 1164,1995. 

Kussmann M, Nordhoff E, Rahbek-Nielsen H, Haebel S, Rossel-Larsen M, Jakobsen L, Gobom J, Mirgorodskaya E, Kroll-Kristensen A, Palm L, Roepstorff P (1997) Matrix-assisted laser desorption/ionization mass spectrometry sample preparation techniques designed for various peptides and protein analytes. J Mass Spectrom 32 593-601... 

Bouschen W, Spengler B (2007) Artifacts of MALDI sample preparation investigated by high-resolution scanning microprobe matrix-assisted laser desorption/ionization (SMALDI) imagine mass spectrometry. Int 1 Mass Spectrom 266 129-137. doi 10.1016/j. ijms.2007.07.017... 

Mirgorodskaya, E., Braeuer, C., Fucini, P, Lehrach, FI. and Gobom, J. (2005a) Nanoflow liquid chromatography coupled to matrix-assisted laser desorption/ionization mass spectrometry Sample preparation, data anlysis, and application to the analysis of complex peptide mixtures. Proteomics 5, 399-408. 

Sample Preparation Using Synthetic Membranes for the Study of Biopolymers By Matrix Assisted Laser Desorption/Ionization Mass Spectrometry... 

While ESI and APCI have been the most commonly used means for the separahon and mass analysis of biotransformahon products, matrix-assisted laser desorphon/ionization (MALDl) and related techniques, such as surface-enhanced laser desorphon/ionization (SELDI) [75] and direct ionizahon off silicon (DIOS) [76], hold promise for rapid screening of biotransformahon samples, and may one day replace much of the work now done by LC-MS for qualitahve studies. The advantage of these techniques over LC-MS is rapid sample analysis, and high-density sample formats that can be prepared robotically. 

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