High performance liquid MALDI

Figure 2.1 Mass spectrometric approach. Dl, direct inlet GC, gas chromatography HPLC, high performance liquid chromatography CZE, capillary zone electrophoresis El, electron ionization Cl, chemical ionization ESI, electrospray ionization DESI, desorption electrospray ionization APCI, atmospheric pressure chemical ionization MALDI, matrix assisted laser desorption ionization B, magnetic analyzer E, electrostatic analyzer...

Strege summarized the technique of high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) in dereplication of natural products. In contrast to earlier electron impact ionization (El), ESI technique is applicable to virtually any ion in solution with a soft ionization process. A comparison of ESI with fast atom bombardment (FAB), matrix assisted laser desorption ionization (MALDI), atmospheric pressure chemical ionization (APCI) and other techniques demonstrates its superior sensitivity, compatibility and reliability when coupled with HPLC [51]. 

The methods for each study are divided into the initial protein separation step, a second separation step if applicable, the type of mass analysis, and the software used for peptide identification. ID = one dimensional polyacrylamide gel electrophoresis, 2D = two dimensional polyacrylamide gel electrophoresis, MS = mass spectrometry (peptide mass fingerprinting), MS/MS = tandem mass spectrometry, MALDI-TOF = matrix assisted laser desorption/ionization-time of flight, MS FIT = software from Protein Prospector, http //prospector.ucsf edu/, ESI = electrospray ionization, Q-TOF = quadrupole-time of flight, PPSS2 =Protana s Proteomic Software Suite (ProtanaEngineering, Odense, Denmark), Mascot = Matiix Science, http //www.matrixscience.com/, TOF-TOF = MALDI plus TOF tandem mass spectrometry, RP-HPLC = reverse phase high performance liquid chromatography, Q-IT = quadrupole ion trap, LIT = linear ion trap. Bioworks = Thermo Electron Corporation. 

A variety of MS formats are widely accepted and applied in the pharmaceutical industry. The specific MS application is often defined by the sample introduction technique. The pharmaceutical applications highlighted in this article feature two types of sample introduction techniques dynamic and static. Dynamic sample introduction involves the use of high-performance liquid chromatography (HPLC) on-line with MS. The resulting liquid chromatography/mass spectrometry (LC/MS) format provides unique and enabling capabilities for pharmaceutical analysis. The electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) modes are the most widely used. Static sample introduction techniques primarily use matrix-assisted laser desorption/ionization (MALDI). ... 

SSCP, single-strand conformation polymorphism PNA-LNA, peptide nucleic acid-locked nucleic acid MALDI-TOF MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ARMS, amplified refractory mutation system dHPLC, denaturing high performance liquid chromatography. 

Figure 6.31. Positive-ion MALDI-TOF reflectron mode mass spectrum of grape seed extract (matrix 2,5-dihydroxybenzoic acid). (Reprinted from Journal of Agricultural and Food Chemistry, 48, Yang and Chien, Characterization of grape procyanidins using high-performance liquid chromatography/mass spectrometry and matrix-assisted laser desorption time-of-flight mass spectrometry, p. 3993, Copyright 2000, with permission from American Chemical Society.)...

Abbreviations APCI Atmospheric Pressure Chemical Ionization DAG Diacyl-glycerols DE Delayed Extraction DHB 2,5-Dihydroxybenzoic Acid El Electron Impact ESI Electrospray Ionisation FACS Fluorescence-activated cell sorting GC Gas Chromatography HDL High Density Lipoprotein HPLC High-Performance Liquid Chromatography IR Infrared LDL Low Density Lipoprotein LOD Level of Detection LOQ Level of Quantification LPC Lyso-Phosphatidylcholine LPL Lyso-Phospholipid MALDI Matrix-... 

SPPS has been enabled through the development of powerful methods for the analysis and subsequent purification of the complex mixture of products typically produced by SPPS. In particular, the development of reversed phase, high performance liquid chromatography (HPLC) and macromolecular mass spectrometry [22], matrix assisted laser desorption/ionization mass spectrometry (MALDI) [23] and electrospray ionization mass spectrometry (ESI-MS)... 

Figure 5. Methods employed for identifiying and characterizing proteins separated by 2DE. Abbreviations used 2DE, two-dimensional electrophoresis ESI, electrospray ionization HPLC, high performance liquid chromatography IR, infrared M, relative molecular mass MALDI, matrix-assisted laser desorption ionization MS, mass spectrometry MS/MS tandem mass spectrometry p/, isoelectric point PSD, post-source decay.

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