Scanning laser desorption/ionization

Figure 4.2 Demonstration of analytical lateral resolution. Scanning laser desorption/ ionization-mass spectrometry (LDI-MS) of the edge between a red and a green felt tip pen coating. Red channel m/z= 122u, anaiyiK...

Tandem mass spectrometry (MS/MS) is a method for obtaining sequence and structural information by measurement of the mass-to-charge ratios of ionized molecules before and after dissociation reactions within a mass spectrometer which consists essentially of two mass spectrometers in tandem. In the first step, precursor ions are selected for further fragmentation by energy impact and interaction with a collision gas. The generated product ions can be analyzed by a second scan step. MS/MS measurements of peptides can be performed using electrospray or matrix-assisted laser desorption/ionization in combination with triple quadruple, ion trap, quadrupole-TOF (time-of-flight), TOF-TOF or ion cyclotron resonance MS. Tandem... 

Welham, K. J. Domin, M. A. Scanned, D. E. Cohen, E. Ashton, D. S. The characterization of micro-organisms by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Comm. Mass. Spectrom. 1998, 12, 176-180. 

Mass spectrometers are used not only to detect the masses of proteins and peptides, but also to identify the proteins, to compare patterns of proteins and peptides, and to scan tissue sections for specific masses. MS is able to do this by giving the mass-to-charge ratio of an ionized species as well as its relative abundance. For biological sample analysis, mass spectrometers are connected to an ionizing source, which is usually matrix-assisted laser desorption ionization (MALDI) [14], surface-enhanced laser desorption/ioni-zation (SELDI, a modified form of MALDI) [15], or electrospray ionization [16]. These interfaces enable the transfer of the peptides or proteins from the solid or liquid phase, respectively, to the gas (vacuum) phase inside the mass spectrometer. Both MALDI and electrospray ionization can be connected to different types of mass analyzers, such as quadrupole, quadruple-ion-traps, time of flight (TOF), or hybrid instruments such as quadrupole-TOF or Fourier transform-ion cyclotron resonance. Each of these instruments can... 

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... 

Since its discovery in 1987, matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has become a common technique in the mass spectral analysis of biopolymers (1, 2). Its ease of operation, theoretically unlimited mass range, and ability to acquire an entire mass spectrum without scanning make the technique an excellent method to analyze high mass biopolymers. Combining such advantages with the capability of analyzing sub-picomole quantities of biopolymers makes MALDI-TOF MS extremely useful for routine mass analysis. 

Recent advances in protein analysis by MS are due to the introduction of electrospray ionization (ESI), matrix-assisted laser desorption ionization (MALDI), MSN scan modes, as well as improvements in instrument sensitivity, resolution, and mass accuracy. With these improved techniques, researchers will continue to use MS to help elucidate primary, secondary, and to a lesser extent, tertiary structure of proteins. 

MS, especially in combination with advanced separation techniques, is one of the most powerful and versatile techniques for the structural analysis of bacterial glycomes. Modern mass spectral ionization techniques such as electrospray (ESI) and matrix-assisted laser desorption/ionization (MALDI) provide detection limits in the high atto- to low femto-mole range for the identification of peptides and complex carbohydrates. Structural characterization of these trace level components can be achieved using tandem MS. This provides a number of specific scanning functions such as product, precursor ion, and constant neutral loss scanning to... 

Spengler, B. and Hubert, M. (2002) Scanning Microprobe Matrix-Assisted Laser Desorption Ionization (SMALDI) mass spectrometry instrumentation for sub-micrometer resolved LDI and MALDl surface analysis. J. Am. Soc. Mass Spectrom., 13, 735-748. 

Bouschen, W., Schulz, O., Eikel, D., and Spengler, B. (2010) Matrix vapor deposition/recrystallization and dedicated spray preparation for high-resolution scanning microprobe matrix-assisted laser desorption/ionization imaging mass spectrometry (SMALDl-MS) of tissue and single cells. Rapid Commun. Mass Spectrom., 24, 355-354. 

We introduced the identification of food colors in foods using TLC/scanning densitometry and consider the method to be sufficiently applicable to routine analyses at facilities such as the Centers of Public Health and the Food Inspection Office. Also, we consider that TLC/ scanning densitometry is applicable to the identification of various food additives, drugs, and pesticides in foods. However, TLC/scanning densitometry has a limitation It can be applied only to samples which have chromo-phores in the molecules. Recently, applications of the TLC/matrix-assisted laser desorption ionization time-of-flight mass spectrometry (TOF-MS), TLC/fast atom bombardment and TLC/multiphoton ioniza-... 

Taki, T. 2012. An approach to glycobiology from glycolipidomics Ganglioside molecular scanning in the brains of patients with Alzheimer s disease by TLC-blot/ matrix assisted laser desorption/ionization-time of flight MS, Biol Pharm. Bull, 35 1642-1647. 

Thermogravimetric analysis Differential thermal analysis Differential scanning calorimetry Thermal volatiUszation analysis Evolved gas analysis Mass spectroscopy methods Matrix-assisted laser desorption/ionization Imaging chemiluminescence... 

After separation, the compounds are ionized prior to mass analysis. The most common techniques for ionization include chemical ionization (Cl), electron impact (El), electron spray ionization (ESI), and matrix-assisted laser desorption ionization (MALDI). Charged compounds are shutded into the mass analyzer which, depending upon the method, selects ions based on predetermined mass-to-charge ratio m/z) criteria, or scans within defined m/z ranges. If tandem mass spectrometry (MS/MS) is... 

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