Mass spectrometers instrumentation

M. L. Magee, J. T. On mass spectrometer instrument standardization and interlaboratory calibration transfer using neural networks. Anal. Chim. Acta 1997,384, 511-532. 

The medium resolution, electron-impact mass spectrum of griseofulvin (Figure 4) was run on a Varian-Mat CH-5 Mass Spectrometer. Instrumental conditions were Electron Energy 70eV Source Temperature 250°C Sample Probe Temperature 140°C. 

Figure 4.2 The micro-Flow Tube Reaetor/Mass Spectrometer instrument. 1 — heated gas inlet/vacuum feedthrough, 2 — hot zone of flow tube, 3 — multiion source block, 4 — ion guide, 5 — quadrupole mass spectrometer, 6 — ion guides, 7 — reaction cell, 8 — quadrupole mass spectrometer, 9 — daly detector... 

All errors due to chemical preparation limit the overall precision of an isotope ratio measmement to usually 0.1-0.2%o, while modem mass spectrometer instrumentation enables a precision better than 0.02%c for light elements other than hydrogen. Larger uncertainties are expected, when elements present in a sample at very low concentration are extracted by chemical methods (e.g., carbon and sulfur from igneous rocks). 

A single capillary scale reverse phase high-performance liquid chromatography system coupled online to automated electrospray ion trap tandem mass spectrometry (ID-LCMS) is usually performed to characterize the protein fractions. The following protocol is an example of the implementation of the method to identify the peptide components of tryptic digests of the yeast HPLC fractions analysis using the ion trap tandem mass spectrometer instrument described in Section 13.2.2.5, and typical results are shown in Figure 13.2-3. 

Experimental variables do, however appear to be critical in obtaining reproducible Cl spectra with ion traps, this is a feature common to all mass spectrometer instruments. But improper selection of RF voltages, time intervals, or operating pressures can yield unexpected results, and could be at the origin of some criticisms concerning this mode of ionization in ion trap mass spectrometry. Obviously, and as a matter of fact, under methane Cl conditions, ion traps present characteristic properties such as a smaller m/z ratio for the CH5 /C2H ions, and a reduced yield of adduct ions [M-f29], [M-f41]. The lack of effective stabilizing conditions for the removal of internal energy has been proposed to account for the absence of such adducts [6]. 

Sysoev, A. Adamov, A. Viidanoja, J. Ketola, R.A. Kostiainen, R. Kotiaho, T., Development of an ion mobility spectrometer for use in an atmospheric pressure ionization ion mobility spectrometer/mass spectrometer instrument for fast screening analysis, Rapid Commun. Mass Spectrom. 2004, 18, 3131-3139. 

In many cases, solvent mixtures are used. Their composition must be identified. Rodofos is one example of such solvent used in Poland. Its composition was determined by gas chromatography. Analyses were performed using a Hewlett-Packard gas chromatograph model 5890 coupled with computerized mass spectrometer instrument, model 5970. 

Accurate isotope ratios often require high-precision mass spectrometers. Instruments capable of such high precision are either ICP-TOF-MS or high-resolution magnetic sector ICP-MS instruments of either the single detector or multicollector type. An excellent fundamental... 

R. Goodacre, E. M. Timmins, A. Jones, D. B. Kell, J. Maddock, M. L. Heginbothom, and J. T. Magee, Anal. Chim. Acta, 348,511 (1997). On Mass Spectrometer Instrument Standardization and Interlaboratory Calibration Transfer Using Neural NetwoAs. 

Knighton,W.B.,Fortner, E.C.,Herndon, S.C.,Wood, E.C., Miake-Lye, R.C. (2009) Adaptation of a proton transfer reaction mass spectrometer instrument to employ NO-h as reagent ion for the detection of 1,3-butadiene in the ambient atmosphere. Rapid Communications in Mass Spectrometry, 23,3301-3308. 

The term Analytical Power refers to the amount of analytical information that can be derived from an analytical instrument. Greater analytical power of an instrument results in more reliable detection, identification and quantitation of samples of interest. For example, a very high degree of analytical power can be derived from a Gas Chromatograph - High Resolution Tandem Mass Spectrometer instrument while... 

We estimate that the accuracies of the relative intensities shown in Fig. 9 are about 30%. Some of the more intense signals are perhaps more accurate than that with respect to each other, but we don t want to suggest that these spectra have the quality obtainable using refined analytical mass spectrometer instruments. For example, we do not obtain a good atom inventory for those explosives in the first column of Fig. 9, but we will discuss this... 

There are two principal components of mass spectrometers the ionization chamber, where ionization of the sample occurs, and the mass analyzer, where ion sorting and detection occur. Mass spectrometer instruments vary in design with regard to both of these components. Thus far we have mentioned only one ionization technique, electron impact (El). In Section 9.18A we discuss El ionization in more detail, as well as discuss two other important ionization methods electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI). 

Goodacre, R., Timmins, E.M., Jones, A., KeU, D.B., Maddock, J., Heginbothom, M.L. and Magee, J.T., On mass spectrometer instrument standardization and interlaboratory calibration transfer using neural networks. Anal. Chim. Acta, 348, 511-532 (1997). 

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