Instrumentation in mass spectrometry

Beynon, J.H. Instruments, in Mass Spectrometry and its Applications to Organic Chemistry, Elsevier Amsterdam, 1960 pp. 4-27. 

Bruimee, C. New Instrumentation in Mass Spectrometry. Int. J. Mass Spec-trom. Ion Phys. 1982,45,51-86. 

A common mistake for beginners in mass spectrometry is to confuse average atomic mass and isotopic mass. For example, the average atomic mass for chlorine is close to 35.45, but this average is of the numbers and masses of Cl and Cl isotopes. This average must be used for instruments that cannot differentiate isotopes (for example, gravimetric balances). Mass spectrometers do differentiate isotopes by mass, so it is important in mass spectrometry that isotopic masses be used... 

This unique reference makes some of the esoteric aspects of this important area of analysis more readily comprehensible to those who deal with analytical instruments but who have not been trained in mass spectrometry. It also serves as a refresher for practicing mass spectroscopists by clarifying principles to afford a better appreciation and application of this technology. 

The progress made in interfacingHPLC instruments with mass spectrometry has been a significant development for laboratory analyses in the pharmaceutical industry. The low concentrations of test drugs in extracts of blood, plasmas, serums, and urine are no problem for this highly sensitive HPLC detector. In addition, the analysis is extremely fast. Lots of samples with very low concentrations of the test drugs can thus be analyzed in a very short time. At the MDS Pharma Services facility in Lincoln, Nebraska, for example, a very busy pharmaceutical laboratory houses over 20 LC-MS units, and they are all in heavy use daily. 

The novel horizons in natural product chemistry are a consequence of advances in mass spectrometry instrumentation. Current applications comprise the elucidation of natural products as part of total extract mixtures in samples of interest to environmental chemists, archaelogists, paleobotanists, geologists, oceanographers, atmospheric chemists, forensic chemists and engineers. The list of applications is expected to expand and some examples are discussed in this chapter. 

MALDI-TOFF MS is a very fast and sensitive technique, implemented on small, relatively inexpensive instruments that do not require extensive expertise in mass spectrometry. Such instruments are ideally suited for biological scientists who need molecular mass information more quickly and more accurately than can be obtained by gel electrophoresis. 

Trends in mass spectrometry focus on the improvement of instrumentation, of several techniques in order to minimize sample volume, to improve sensitivity and to reduce detection limits. This is combined with increasing the speed of several analyses, with automation of analytical procedures and subsequently reducing the price of analysis. A minimizing of sample volumes means a reduction of waste volume with the aim of developing green chemistry . Furthermore, new analytical techniques involve a development of quantification procedures to improve the accuracy and precision of analytical data. Special attention in future will be given to the development of hyphenated mass spectrometric techniques for speciation analysis and of surface analytical techniques with improved lateral resolution in the nm scale range. 

A quite different type of mass spectrometer - the first 180° magnetic sector field mass spectrometer (see Figure 1.7), with directional focusing of ions for isotope analysis, was constructed by Dempster, independently of other instrumental developments in mass spectrometry, in 1918. 

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