Tandem methods mass spectrometry

Figure 2.7. Identification ofphosphoproteins by site-specific chemical modification. A. Method of Zhou et al. (2001) involves trypsin digest of complex protein mixture followed by addition of sulfhydryl groups specifically to phosphopeptides. The sulfhydryl group allows capture of the peptide on a bead. Elution of the peptides restores the phosphate and the resulting phosphopeptide is analyzed by tandem mass spectrometry. B. Method of creates a biotin tag in place of the phosphate group. The biotin tag is used for subsequent affinity purification. The purified proteins are proteolyzed and identified by mass spectrometry.

Johnson R.S. and Taylor J.A. (2000), Searching sequence databases via de novo peptide sequencing by tandem mass spectrometry, in Methods in Molecular Biology, Vol. 146, Mass Spectrometry of Proteins and Peptides, pp. 41-61, Chapman J.R., Ed., Humana Press, Totowa, NJ. 

Macek et al. [120] developed a method to quantitate omeprazole in human plasma using liquid chromatography-tandem mass spectrometry. The method is based on the protein precipitation with acetonitrile and a reversed-phase liquid chromatography performed on an octadecylsilica column (55 x 2 mm, 3 /im). The mobile phase consisted of methanol-10 mM ammonium acetate (60 40). Omeprazole and the internal standard, flunitra-zepam, elute at 0.80 0.1 min with a total rim time 1.35 min. Quantification was through positive-ion made and selected reaction monitoring mode at m/z 346.1 —> 197.9 for omeprazole and m/z 314 —> 268 for flunitrazepam, respectively. The lower limit of quantification was 1.2 ng/ml using 0.25 ml of plasma and linearity was observed from 1.2 to 1200 ng/ml. The method was applied to the analysis of samples from a pharmacokinetic study. 

Frerichs et al. [128] developed and validated a method for the quantitation of omeprazole and hydroxyomeprazole from one 250 [A sample of human plasma using HPLC coupled to tandem mass spectrometry. The method was validated for a daily working range of 0.4-100 ng/ml, with limits of detection between 2 and 15 pg/ml. The interassay variation was less than 15% for all analytes at four control concentrations and the samples were stable for three freeze-thaw cycles under the analysis conditions and 24 h in the postpreparative analysis matrix. The method was used to analyze samples in support of clinical studies probing the activity of the cytochrome P-450 enzyme system. 

Dahn T, Gunn J, Kriger S, Terrell AR (2010) Quantitation of morphine, codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and 6-monoacetylmorphine (6-MAM) in urine, blood, serum, or plasma using liquid chromatography with tandem mass spectrometry detection. Methods Mol Biol 603 411 122... 

March, R. Brodbelt, J. 2008. Analysis of flavonoids Tandem mass spectrometry, computational methods, and NMR. J. Mass Spectrom. 43 1581-1617. 

Streit F, Armstrong VW, OeUerich M. Rapid liquid chromatography-tandem mass spectrometry routine method for simultaneous determination of sirolimus, everolimus, tacrolimus, and cyclosporin A in whole blood. Clin Chem 2002 48 955-8. 

Kallio, H. and Currie, G. (1993) Analysis of lowerucic acid turnip rapeseed oil by negative ion chemical ionization tandem mass spectrometry. A method giving information on the fatty acid composition in positions sn-2 and sn-lB of triglycerols. Lipids, 28, 207-215. 

Johnson reported at the 59th TSRC, in 2005, on the results of the identification of spin-trapped vapor-phase free radicals in MSS via an ESI-triple quadrupole tandem mass spectrometry analysis method. Four alkoxyl free radicals were unequivocally identified (OC2H5, OC3H7, OC4H9, and OCjHjj). The superoxide free radical was also tentatively identified (27A56). 

Isotope-coded affinity tag (ICAT) peptide labeling is an approach that combines accurate quantification and concurrent sequence identification of individual proteins in complex mixtures (Gygi, et al 1999). This method is based on a newly synthesized class of chemical reagents used in combination with tandem mass spectrometry. The method consists of four steps ... 

Dubreil-Cheneau E, Bessiral M, Roudaut B, Verdon E, Sanders P, Validation of a multi-residue liquid chromatography-tandem mass spectrometry confirmatory method for 10 anticoccidials in eggs according to Commission Decision 2002/657/EC, J. Chromatogr. A 2009 1216(46) 8149-8157. 

Tandem methods for chemical measurements are now widely accepted and employed even when tandem is defined in the narrowest sense, such as two-dimensional gas chromatography or tandem mass spectrometry. Tandem or triple quadrupole MSs became commercially available in the early 1980s, and today these instruments are routine concepts as linear quadrupole analyzers or as ion traps. Tandem or sequential methods result in loss of signal current, yet noise is lost more so thus, S/N is increased. 

Xu, J., Dong, R, Liu, X., Li, J., Li, Y., Shan, W., and Zheng, Y. 2012. Determination of sulfoxaflor residues in vegetables, fruits and soil using ultra-performance liquid chroma-tography/tandem mass spectrometry. Anal. Methods 4 4019-4024. 

March R, Brodbelt J. Analysis of flavonoids tandem mass spectrometry, computational methods, andNMR. J Mass Spectrom. 2008 43 1581-617. 

R. March and J. Brodbelt, Analysis of Flavonoids Tandem Mass Spectrometry, Computational Methods, and NMR , J. Mass Spectrom., 2008, 43, 1581. 

Nesvizhskii, A.I. Vitek, O. Aebersold, R. Analysis and Validation of Proteomic Data Generated by Tandem Mass Spectrometry. Nature Methods 2007, 4, 787-797. 

Recent research has included the areas of laser fluorescence spectrometry, mass spectrometry, tandem accelerator mass spectrometry and improvements in neutron activation analysis (Brauer and Strebin, 1979 Elmore et al., 1980 Goles et al., 1981 Bate and Stokely, 1982 Brauer et al., 1982 Stoffels, 1982). Neutron activation continues to be the method used for most low level analyses. 

Nesvizhskii,A.L, Vitek, O., and Aebersold, R. (2007) Analysis and validation of proteomic data generated by tandem mass spectrometry. Nature Methods, 4,787-797. 

An on-line chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCI/MS/MS) methods was developed for rapid screen of pharmacokinetics of different drugs, including 5 (98RCM1216). The electron impact mass spectrum of 5 and ethyl 9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7Ff-pyrido[l,2,3- fe]-l,4-benzoxazine-6-carboxylate was reported (97MI28). Electron impact/Fourier transform... 

Tandem mass spectrometry (MS/MS) is a method for obtaining sequence and structural information by measurement of the mass-to-charge ratios of ionized molecules before and after dissociation reactions within a mass spectrometer which consists essentially of two mass spectrometers in tandem. In the first step, precursor ions are selected for further fragmentation by energy impact and interaction with a collision gas. The generated product ions can be analyzed by a second scan step. MS/MS measurements of peptides can be performed using electrospray or matrix-assisted laser desorption/ionization in combination with triple quadruple, ion trap, quadrupole-TOF (time-of-flight), TOF-TOF or ion cyclotron resonance MS. Tandem... 

Kasprzyk-Hordern B, Dinsdale RM, Guwy AJ (2008) Multiresidue methods for the analysis of pharmaceuticals, personal care products and illicit drugs in surface water and wastewater by solid-phase extraction and ultra performance liquid chromatography-electrospray tandem mass spectrometry. Anal Bioanal Chem 391(4) 1293-1308... 

Kasprzyk-Hordern B, Dlnsdale RM, Guwy AJ (2007) Multi-residue method for the determination of basic/neutral pharmaceuticals and illicit dmgs in surface water by solid-phase extraction and ultra performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry. J Chromatogr A 1161 132-145... 

Castiglioni S, Bagnati R, Calamari D, Fanelli R, Zuccato E (2005) A multiresidue analytical method using solid-phase extraction and high-pressure liquid chromatography tandem mass spectrometry to measure pharmaceuticals of different therapeutic classes in urban waste-waters. J Chromatogr A 1092 206-215... 

Gros M, Petrovic M, Barcelo D (2006) Development of a multi-residue analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS-MS) for screening and trace level determination of pharmaceuticals in surface and wastewaters. Talanta 70 (4) 678-690... 

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