Biomolecules, mass spectrometry

Due to the inherent complexity of biological samples and to the lack of chromophores in the case of various biomolecules, mass spectrometry would be the ultimate technique to complement CEC in analysis of real-life biological mixtures. In the past 10 years, this aspect has been recognized and numerous groups have worked on developing suitable interfaces for coupling CEC to MS. Mixtures of neutral isomeric compounds derived from the in-vitro reaction of... 

FW McLafferty, EK Fridriksson, DM Horn, MA Lewis, RA Zubarev. Biochemistry—biomolecule mass spectrometry. Science 284 1289—1290, 1999. 

McLafferty FW, Fridriksson EK, Horn DM, Lewis MA, Zubarev RA (1999) Tech-view Biochemistry, Biomolecules Mass Spectrometry. Science 284 1289... 

M. Frank, S. E. Labov, G. Westmacott, and W. H. Bener, Energy-sensitive cryogenic detectors for high-mass biomolecule mass spectrometry. Mass Spectrom. Rev. 18, 155-186 (1999). 

Relative mass is an intrinsic molecular property which, when measured with high accuracy, becomes a unique and unusually effective parameter for characterization of synthetic or natural biomolecules. Mass spectrometry based methods can be broadly applied not only to unmodified synthetic biomolecules, but also to modified synthetic and natural biomolecules (e.g. glycosylated proteins). The level of mass accuracy one obtains during the measurement will depend on the capabilities of the mass analyser used. Quad-rupole and TOE instruments yield lower mass accuracies than sector or Fourier transform ion cyclotron resonance (FTICR) instruments. High mass accuracy is not only necessary for qualitative analysis of biomolecules present in a sample, but is necessary to provide unambiguous peak identification in a mass spectrum. 

Modern commercial lasers can produce intense beams of monochromatic, coherent radiation. The whole of the UV/visible/IR spectral range is accessible by suitable choice of laser. In mass spectrometry, this light can be used to cause ablation, direct ionization, and indirect ionization (MALDI). Ablation (often together with a secondary ionization mode) and MALDI are particularly important for examining complex, intractable solids and large polar biomolecules, respectively. 

Matrix-assisted laser desorption mass spectrometry (MALDI-MS) is, after electrospray ionization (ESI), the second most commonly used method for ionization of biomolecules in mass spectrometry. Samples are mixed with a UV-absorbing matrix substance and are air-dried on a metal target. Ionization and desorption of intact molecular ions are performed using a UV laser pulse. 

The mass spectrum produced should provide unambiguous molecular weight information from the wide range of compounds amenable to analysis by HPLC, including biomolecules with molecular weights in excess of 1000 Da. The study of these types of molecule by mass spectrometry may be subject to limitations associated with their ionization and detection and the mass range of the instrument being used. 

Metastable atom bombardment (MAB) is a novel ionization method for mass spectrometry invented by Michel Bertrand s group at the University of Montreal, Quebec, Canada, and described by Faubert et al.38 For the identification of bacteria by MS, MAB has a number of significant advantages relative to more familiar ionization techniques. Electron ionization (El) imparts so much excess energy that labile biomolecules break into very small fragments, from which the diagnostic information content is limited since all... 

Flowever, the object being analyzed has to be removed from the tissues. Thus, information about the distribution of the target in the organism or in the cells is inevitably lost. What is now needed is a technology to acquire information about the distribution of the biomolecule simultaneously with its identification. The method used for this purpose, called imaging mass spectrometry (IMS), is as follows. The tissue sample is cut into thin slices, and a matrix that assists the ionization of macromolecules is spread onto these slices. The macromolecules are then ionized by a scanning laser, and the generated ions are detected and analyzed by MS.1... 

Moritake S, Taira S, Sugiura Y, et al. Magnetic nanoparticle-based mass spectrometry for the detection of biomolecules in cultured cells. J. Nanosci. Nanotechnol. 2009 9 169-176. 

R. D. Macfarlane. Mass Spectrometry of Biomolecules From PDMS to MALDI. Brazilian J. Phys., 29(1999) 415-420. 

B. Spengler. Post-Source Decay Analysis in Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry of Biomolecules. J. Mass Spectrom., 32(1997) 1019-1036. 

High resolution mass spectrometry becomes indispensable for the analysis of biomolecules with ESI (see Chapter 2, Section 2.1.15) and MALDI (see Section 2.1.22) techniques. In these cases very high resolving power and accuracy of measurements are required to measure reliably the real masses of the sample molecules. 

Mahmoud Hamdan and Pier Giorgio Righetti Proteomics Today Protein Assessment and Biomarkers Using Mass Spectrometry, 2D Electrophoresis, and Microarray Technology Igor A. Kaltashov and Stephen J. Eyles Mass Spectrometry in Biophysics Confirmation and Dynamics of Biomolecules... 

L.J. Deterding, M.A. Moseley, K.B. Tomer and J.W. Jorgenson, Coaxial continuous flow fast atom bombardment in conjunction with tandem mass spectrometry for the analysis of biomolecules, Anal. Chem., 61 (1989) 2504-2511. 

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