Tandem mass spectrometry programming

Full acceptance of HPLC/MS methods by the US EPA OPP as enforcement methods occurred between 1998 and 2001. For example, in 1998, the EPA OPP accepted HPLC/MS (without MS/MS) methods as primary enforcement methods, and high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) only was suitable for confirmatory methods. However, in 2001, HPLC/MS/MS methods also became acceptable for primary enforcement. Table 4 summarizes the types of methods that were validated by the EPA OPP method validation program, for both food tolerance enforcement methods and environmental chemistry methods. 

Table 2.1.3 Multiple reaction monitoring of amino acids for their tandem mass spectrometry quantitation. In daily practise not all mentioned amino acids are measured in one run, but a set of ten dedicated evaluation programs has been developed, covering groups of amino acids associated with groups of disorders. Amino acids presented in italics indicate stable-isotope-labeled internal standards ... 

Besides this spatial separation method using successive analysers, tandem mass spectrometry can also be achieved through time separation with a few analysers such as ion traps, orbitrap and FTICR, programmed so that the different steps are successively carried out in the same instrument. This method was described in the case of the ion traps and FTMS in Chapter 2. The maximum practical number of steps for these instruments is seven to eight. In these instruments the proportion of ions transmitted is high, but at each step the mass of the fragments becomes lower and lower. 

Jean H. Futrell is Senior Battelle Fellow and Chief Science Officer at Pacific Northwest National Laboratory. Previously he was Willis F. Harrington Professor of Chemistry and Biochemistry at the University of Delaware. He received a B.S. from Louisiana Polytechnic Institute and a Ph.D. from University of California at Berkeley. Futrell s research program focuses on the application of reaction dynamics methods—particularly the use of crossed molecular beams—to investigate the detailed mechanism of ion activation in tandem mass spectrometry. He has served on the NRC s Chemical Sciences Roundtable and was chair of the Council for Chemical Research in 1999. 

Kil YJ, Becker C, Sandoval W, et al. Preview a program for surveying shotgun proteomics tandem mass spectrometry data. Anal Chem. 2011 83 5259 7. doi 10.1021/ac200609a. 

Given the large number of compounds that are monitored in sports doping control programs no single screening method can detect all the relevant componnds. Therefore, liqnid chromatography/tandem mass spectrometry (LC-MS/MS) methods are typically nsed in conjunction with other techniqnes snch as gas... 

The quickest technique for checking banknotes, developed by a group in Bristol, involves tandem mass spectrometry. If the note is heated up to 285°C for a second, the cocaine molecules are released and carried on a stream of air into the spectrometer. Once inside the spectrometer, the cocaine molecules are ionized and also get protonated. If this ion bumps into other ions, the cocaine molecular ion can split into smaller fragment ions. If the spectrometer is looking for cocaine, it is programed to pick out the peaks with m/z values of 182 and 105, the two main fragments of the molecular ion, and also to measure their intensities. The technique is sensitive and very rapid it can check... 

Fernandez-Gonzalez V, Muniategui-Lorenzo S, Lopez-Mahia P, Prada-Rodriguez D (2008) Development of a programmed temperature vaporization-gas chromatography-tandem mass spectrometry method for polycychc aromatic hydrocarbons ancilysis in biota samples at ultratrace levels. J Chromatogr A 1207 136-145... 

Chen, T., Kao, M.-Y, Tepel, M., Rush, J. and Church, G., A dynamic programming approach to de novo peptide sequencing via tandem mass spectrometry./. Comput. Biol, 8(3), 325-337 (2001). 

Figure 3 Third dimension in pyrolysis mass spectrometry approaches (A) linear programmed thermal degradation mass spectrometry [LPTDMS - third dimension = temperature] (B) collisionally activated dissociation of parent ions coupled with scanning of product ions using tandem mass spectrometry [MS/ MS - third dimension = spectrum of product ions] (C) laser microprobe mass analyser [LAMMA - third dimension = spatial resolution].

Figure 20.9. Two-dimensional mass spectrometric analysis of GPIns molecular species in a lipid extract of mouse myocardium. The lipid extract of mouse myocardium was prepared by a modified Bligh and Dyer procedure as previously described. Each MS or MS/MS trace of the 2D ESI mass spectrum was acquired by sequentially programmed, customized scans operating under Xcalibur software. For negative-ion tandem mass spectrometry in the precursor-ion (PI) mode, the first quadrupole was scanned in the selected mass range and the second quadrupole was used as a coUision cell while the third quadrupole was fixed to monitor the ion of interest (i.e., either inositol phosphate, glycerophosphate, or a fatty acyl carboxylate fragmented from GPIns molecular species). All mass spectral traces were displayed after being normalized to the base peak in each individual trace.

The chromatograph had an all glass linear splitter (split 80 1) and a helium linear velocity of 23 cm/sec. A Perkin-Elmer fused silica column was used which measured 0.235 mm id, x 25 m long and which was coated with OV-101 (methyl silicone) liquid phase. The column was held 4 min at 45°C then programmed at 3°c/min to 120°C. Mass spectra were obtained using tandem gas chromatography/mass spectrometry. The column effluent was passed into the ion source of a DuPont Model 21-491 mass spectrometer (DuPont Instrument Division, Wilmington, Delaware). Mass spectra were obtained at 70 eV and a source temperature of 200°C. 

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