Multiple mass spectrometry

U. Berger, M. Oehme and F. Kuhn, Quantitative determination and structure elucidation of type A-and B-trichothecenes by HPLC/ion trap multiple mass spectrometry, 7. Agric. Fd. Chem., 47, 4240-4245 (1999). 

B. R. Larsen, C. Astorga-Llorens, M. H. Florencio, A. M. Nettencourt, Fragmentation pathways of organoarsenical compounds by electrospray ion trap multiple mass spectrometry (MS6), J. Chromatog. A, 926 (2001), 167-174. 

Identification and quantification of low molecular weight and volatile phenols is usually performed by Gas Chromatography and Mass Spectrometry (GC-MS). For analysis and structural characterization of more polar compounds such as polyphenols, liquid-phase and Liquid Chromatography Mass Spectrometry (LC-MS) and Multiple Mass Spectrometry (MS/MS and MSn) techniques are used (Niessen and Tinke, 1995 de Hoffmann, 1996 Abian, 1999 Flamini et al., 2007). 

Wiele Van de, M., De Wasch, K., Vercammen, J., Courtheyn, D., De Brabander, H. and Impens, S. (2000). Determination of 163-hydroxystanozolol in urine and faeces by bquid chromatography-multiple mass spectrometry. 7. Chromatogr. A, 904, 203-209. 

Currently, LC/MS and multiple mass spectrometry (MS/MS) have been used to study the grape polyphenols (anthocyanins, flavonols, tannins and proanthocyanidins, hydroxycinnamic, and hydroxycinnam-oyltartaric acids), which allow to structurally characterize and understand the mechanisms involved in stabilizing the color in wines (Flamini, 2003). 

A GC/ITMS analysis of propanil, acetochlor, myclobutanil, and fenoxycarb in grape juice and wine is performed by recording signals of the collision-produced ions formed by multiple mass spectrometry (MS/MS) reported in Table 9.9. Data in the table compare the GC/ MS-SIM and GC/MS-MS methods used for analysis of these pesticides in grape juice and wine. The two methods have a similar precision and sensitivity in wine analysis, with IT providing a lower sensitivity in the grape juice analysis. 

Detection, characterization, and identification of metabolites require multiple mass spectrometry experiments such as full scan LC/MS and LC/MS/MS. The process becomes very time consuming, particularly when a large number of metabolites are formed. The interpretation of LC/MS/MS data is very laborious and inefficient, and can be a rate-limiting step in the metabolite identification process. Therefore, new approaches to data acquisition that would minimize the need for multiple experiments, and data processing tools that would simplify mass spectral interpretation, are highly desired. 

A series of surveys and reviews [28, 44, 45, 293] dealt with the simultaneous determination of a broad range of polar compounds in environmental samples by API interfaces. Possibilities and Hmitations of stmcture elucidation by bC-ion trap multiple mass spectrometry (bC-ITMS ) were the topic overview [38]. As shown later, pesticide residue analysis was the most frequent application of bC-MS in water sample analysis, as the number of review articles on the subject of pesticide analysis and their degradation products demonstrates [20, 22, 29, 30, 32, 199, 294], The analysis of dyes by means of API interfacing techniques was reviewed by three groups [43, 161, 200], while the bC-MS analysis of surfactants, as compounds of environmental concern, was comprehensively reviewed [21]. 

Melchert, H.-U. Pabel, E (2004). Reliable identification and quantification of trichothecenes and other mycotoxins by electron impact and chemical ionization-gas chromatography-mass spectrometry, using an ion-trap system in the multiple mass spectrometry mode. Candidate reference method for complex matrices. Journal of Chromatography A, Vol. 1056, No. 1-2, (November 2004), 195-199, ISSN 0021-9673. 

Rivier L (2003) Criteria for the identification of compounds by liquid chromatography-mass spectrometry and liquid chromatography-multiple mass spectrometry... 

Schneider, M.J. Donoghue, D.J. Multiresidue analysis of fluoroquinolone antibiotics in chicken tissue using liquid chromatography-fluorescence-multiple mass spectrometry, J.Chromatogr.B, 2002, 780, 83 92. [ciprofloxacin norfloxacin danofloxadn enrofloxacin orbifloxacin sarafloxacin difloxacin LOQ 10 n g]... 

Biancotto, G, Angeletti, R., Piro, R.D., et al. (1997) Ion trap high-performance liquid chromatography/multiple mass spectrometry in the determination of beta-agonists in bovine mines. Journal of Mass Spectrometry, 32,781-784. 

Mateus-Avois, L., Mangin, R, and Saugy, M. (2005) Use of ion trap gas chromatography-multiple mass spectrometry for the detection and confirmation of 3 hydroxystanozolol at trace levels in urine for doping control. Journal of Chromatography B, Analytical Technologies in the Biomedical and Life Sciences, 816,193-201. 

Most of the previous discussion has concerned addition. Subtraction in binary is very similar, but multiplication is awkward (try it ). For this reason it is quicker for a computer to multiply by carrying out a series of additions. Multiplying 3x5 becomes adding 5 -(- 5 -(- 5. Because each addition is very fast, the time taken for even a large multiplication is very little and still appears instantaneous to us. Only with very large computations does this speed become obvious enough to merit special computers, more powerful than the ones being considered here for use in mass spectrometry. Finally, division is very similar to multiplication, except that a series of subtractions is carried out instead of additions. 

When multicharged ions are formed, the simple rule of thumb used widely in mass spectrometry that m/z = m because, usually, z = 1 no longer applies for z > 1 then m/z < m, and the apparent mass of an ion is much smaller than its true mass. Accurate mass measurement is much easier at low mass than at high, and the small m/z values, corresponding to high mass with multiple charges, yield accurate values for the high mass. 

Because of the complexity of the polyether antibiotics tittle progress has been made in stmcture determination by the chemical degradation route. X-ray methods were the techniques most successfully applied for the early stmcture elucidations. Monensin, X206, lasalocid, lysocellin, and salinomycin were included in nineteen distinct polyether x-ray analyses reported in 1983 (190). Use of mass spectrometry (191), and H (192) and nmr (141) are also reviewed. More recently, innovative developments in these latter techniques have resulted in increased applications for stmcture determinations. Eor example, heteronuclear multiple bond connectivity (hmbc) and homonuclear Hartmann-Hahn spectroscopy were used to solve the stmcture of portimicin (14) (193). East atom bombardment mass spectrometry was used in solving the stmctures of maduramicin alpha and co-factors (58). 

Figure 5.64 LC-UV and LC-MS-MS (multiple-reaction monitoring (MRM)) traces from the analysis of a synthetic mixture of four native and five oxidized deoxynucleosides (for nomenclature, see text). Reprinted by permission of Elsevier Science from Comparison of negative- and positive-ion electrospray tandem mass spectrometry for the liquid chromalography-landem mass speclrometry analysis of oxidized deoxynucleosides , by Hua, Y., Wainhaus, S. B., Yang, Y., Shen, L., Xiong, Y., Xu, X., Zhang, F., Bolton, J. L. and van Breemen, R. B., Journal of the American Society for Mass Spectrometry, Vol. 12, pp. 80-87, Copyrighl 2000 by Ihe American Society for Mass Spectrometry.

COWARD L, KIRK M, ALBIN N and BARNES s (1996) Analysis of plasma isoflavones by reversed-phase HPLC-multiple reaction ion monitoring-mass spectrometry. Clin Chim Acta. 247 (1-2) 121-42. 

A further extension of the DFG S19 method was achieved when polar analytes and those unsuitable for GC were determined by LC/MS or more preferably by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Triple-quadrupole MS/MS and ion trap MS" have become more affordable and acceptable in the recent past. These techniques provide multiple analyte methods by employing modes such as time segments, scan events or multiple injections. By improving the selectivity and sensitivity of detection after HPLC separation, the DFG S19 extraction and cleanup scheme can be applied to polar or high molecular weight analytes, and cleanup steps such as Si02 fractionation or even GPC become unnecessary. 

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

LC/MS/MS. LC/MS/MS is used for separation and quantitation of the metabolites. Using multiple reaction monitoring (MRM) in the negative ion electrospray ionization (ESI) mode, LC/MS/MS gives superior specificity and sensitivity to conventional liquid chromatography/mass spectrometry (LC/MS) techniques. The improved specificity eliminates interferences typically found in LC/MS or liquid chro-matography/ultraviolet (LC/UV) analyses. Data acquisition is accomplished with a data system that provides complete instmment control of the mass spectrometer. 

Multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) combines sector-field ICPMS with a multiple collector detector system and has recently emerged as an alternative to TIMS for precise U-Th isotope measurement. The full potential of MC-ICPMS has yet to be realized. Yet despite this, its performance in high precision isotope measurement already challenges and, in some cases, surpasses that ever achieved by TIMS (e.g., Lee and Halliday 1995 Blichert-Toft and Albarede 1997). 

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