Mass Spectrometry Based Systems

While most of the commercially available gas sensors are based on one of the aforementioned four major sensor technologies, MS sensors are based on a measuring technique well known and widely used for almost 30 years MS. 

Ion mobility spectrometry (IMS), which has the ability to separate ionic species at atmospheric pressure, is another technique that is useful for detect and characterising organic vapours in air [97]. This involves the ionisation of molecules and their subsequent drift through an electric field. Analysis is based on analyte separations resulting from ionic mobilities rather than ionic masses. A major advantage of operation at atmospheric pressure is that it is possible to have smaller analytical units, lower power requirements, lighter weight and easier use. 

Other MS-fingerprinting techniques that are in commercial development are based on atmospheric pressure ionisation (API), resonance-enhanced multiphoton ionisation (REMPI) TOE and proton-transfer reaction (PTR). They are rapid, sensitive and specific and allow measurements in real time and may play an increasingly important role in the future development of electronic noses and tongues. 

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DB Kassel. A fully automated mass spectrometry based system for the rapid analysis and purification of combinatorial libraries. Solid and Solution Phase Combinatorial Synthesis, New Orleans, 1997. 

Tani, A., Kato, S., Kajii, Y., Wilkinson, M., Owen, S., Hewitt, N. (2007) A proton transfer reaction mass spectrometry based system for determining plant uptake of volatile organic compounds. Atmospheric Environment, 41,1736-1746. 

Ivanova, P.T., Milne, S.B., Myers, D.S. and Brown, H.A. (2009) Lipidomics A mass spectrometry based systems level analysis of cellular lipids. Curr. Opin. Chem. Biol. 13, 526-531. 

One is compelled to pose the question if experimentally it will become possible to decide whether the 14C variations observed on tree-ring samples, peat bogs, sediments, etc., are primarily caused by an external forcing of the system (production rate variations) or by an internal one. Recent progress in detection of small numbers of nuclei of an isotope by mass spectrometry based on the use of a particle accelerator [57,58] make it possible to measure the cosmic ray produced 10Be or 36C1 deposited in only 1 kg of ice. These isotopes get attached to aerosol particles and deposited with them. 

The mass spectrometric information should ideally be sufficient to answer two questions about each sample what does it contain and how much In order to answer these questions appropriately a researcher has to face the three central problems of mass spectrometry based proteomic research (i) the design of the experiment to allow for detection of proteins that are present in low abundance in the biological system... 

Syage, J. A., K. A. Hanold, and M. A. Hanning-Lee. Mass spectrometry based personnel screening system. Proc. INMM—42nd Annual Meeting, Palm Springs, CA, 2001. 

Dittmann, B., Nitz, S. (2000) Strategies for the development of reliable QA/QC methods when working with mass spectrometry-based chemosensory systems. Sens. Actuators B 69 253-257. 

Developments in mass spectrometry technology, together with the availability of extensive DNA and protein sequence databases and software tools for data mining, has made possible rapid and sensitive mass spectrometry-based procedures for protein identification. Two basic types of mass spectrometers are commonly used for this purpose Matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF) mass spectrometry (MS) and electrospray ionization (ESI)-MS. MALDI-TOF instruments are now quite common in biochemistry laboratories and are very simple to use, requiring no special training. ESI instruments, usually coupled to capillary/nanoLC systems, are more complex and require expert operators. We will therefore focus on the use of MALDI-... 

Careri M, Mangia A (2006) Validation and qualification the fitness for purpose of mass spectrometry-based analytical methods and analytical systems. Anal Bioanal Chem 386 38-45... 

J.A. Syage, K.A. Hanold, and M.A. Hanning-Lee, Mass Spectrometry Based Personnel Screening System, 42nd INMM Meeting, Phoenix, AZ, 2001. 

Frank, M., Ulmer, H., Ruiz, J., Visani, P., and Weimar, U. (2001). Complementary analytical measurements based upon gas chromatography-mass spectrometry, sensory system and human sensory panel A case study dealing with packaging materials. Anal. Chim. Acta 431,11-29. 

MALDI and ESI represent the predominant ionization techniques in mass spectrometry-based proteomics, as recognized by the Nobel Prize in chemistry in 2002. MALDI is mainly used to volatize and ionize simple polypeptide samples for mass spectrometric (MS) analysis at high speed. The analysis of more complex peptide mixtures is usually conducted via ESI mass spectrometry (ESI MS) coupled online with a high-pressure liquid chromatography (HPLC) system to concentrate and separate peptides prior to MS analysis. 

FIGURE 18.1 The mass spectrometry-based analytical process flow depicting systems related to process and data automation. 

Another way to speed up HPLC that does not interfere with the existing gradient separation method is by parallel operation of several HPLC columns. The development in this direction started a couple of years ago when fast gradient separation was first combined with mass spectrometry-based detection. Parallel column operation was achieved by a single pumping system and a splitter tee that transferred the gradient flow onto two HPLC columns. The effluent of the two columns was simultaneously sprayed into a modified ion spray interface of a quadrupole mass spec-trometer. From the overlay chromatogram both desired and previously known compounds were identified after their molecular ions were filtered from the total ion current (TIC). In this first system, however, it was difficult to enhance the parallelization, and the detection system created a bottleneck. ... 

Theodoridis, G., Gilka, H. G., and Wilson, I. D. 2011. Mass spectrometry-based holistic analytical approaches for metabolite profiling in systems biology studies. Mass Spectrom. Rev. 30 884-906. 

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