Mass frontier

Fig. 1.41 (A) Product ion spectrum of remikiren obtained on a QqTOF. (B) Software-predicted fragments (Mass Frontier, HighChem) for the ion at m/z 282.

In addition to software tools to help postacquisition processing, software tools to help mass spectral interpretation, particularly MS/MS, have taken new strides as well (Heinonen et al., 2008). One example of such a software tool is the MathSpec program. The details of the MathSpec approach have been explained (Sweeney, 2003). MathSpec software is used in conjunction with MS/MS spectra obtained under high-resolution conditions. The software systematically attempts to assemble possible parts (from the MS/MS fragment data) of the molecule into a rational molecule. Other examples of structure elucidation software include HighChem s Mass Frontier and ACD/Labs ACD/MS Manager (Bayliss et al., 2007). Other metabolite prediction software tools such as Meteor are also being incorporated into LC-MS software as tools to help accelerate metabolite detection and characterization (Testa et al., 2005 Ives et al., 2007). 

Wang Q, Zhao JG, Ballard JM, Shambor SM, Tsai EW, Ip D. 1999. Application of tandem mass spectrometry to FOSAMAX dissolution testing, presented at the Mass Frontier Symposium, Purdue University, October 10, 1999. 

Lim et al. [93] investigated the use of LTQ-Orbitrap to identify human liver microsomal metabolites of carvedilol, using parent mass list triggered data-dependent multiple stage accurate mass analysis. In this study, LTQ-Orbitrap was used for accurate mass measurements at a resolving power of 60,000 to obtain mass accuracy <2 ppm for all full-scan and MS" spectra in the external calibration mode. The chemical formulas obtained from high-resolution accurate mass measurements were used to confirm structures of the product ions proposed by Mass Frontier. 

FIGURE 10.7 Full-scan accurate mass spectrum of nefazodone (m/z 470) acquired in the Orbitrap mass spectrometer using external mass calibration. The expanded spectrum showed the low-intensity product ions. Product ion assignment resulted from predictive fragmentation using Mass Frontier 4.0. 

Including library spectra for Mass Frontier improved the match values, but had a slight adverse effect on the RRP, while the calculation time increased dramatically (e.g. from minutes to hours) ... 

The best RRP Mass Frontier 3 step) is only slightly better than that for MOLGEN-MS. 

HighChem Ltd. Mass Frontier. HighChem Ltd./Thermo Fisher Scientific, Bratislava, Slovakia, 2012. 

Since the data obtained by low resolution instruments, like QqQ, are enough simple to interpret if compared with the huge amount of data obtained by a HR instrument, interpretation of a product ion spectrum generated by the QqQ is often not straightforward, because of the complex dissociation mechanisms for formation of fragment ions. However, a structure elucidation software, such as ACD/MS Fragmenter or Mass Frontier, developed to predict the fragment ions formed by Cff), has been used to assist the spectral interpretation of unknown structures. 

Keywords product safety pharmaceutical product packaging quality control AMDIS deconvolution unknown identification Mass Frontier spectrum interpretation... 

Mass spectra not satisfactorily identified by hbrary search were analyzed in the fragmentation pattern by using Mass Frontier resulting in structural... 

For unknown mass spectra the Mass Frontier software is a unique tool for spectrum interpretation. Structure proposals and fragmentation pathways are provided for mass spectra allowing a deeper sample and unknown elucidation. 

Keywords chemical analysis identification chemical ionization molecular ion MS/MS ion trap amines Mass Frontier fragmentation pathways... 

PCI with methane and ammonia was used to form the molecular ion, which in the next steps was fragmented for structural elucidation by MS/MS. The Thermo Scientific Mass Frontier software was then used to predict the theoretical fragments and fragmentation pathways of the detected product ions to confirm their identity. 

The high intensity quasi-molecular ion is the ideal precursor for MS/MS. The product ion spectrum with the fragment ion structures predicted by Mass Frontier software for the protonated molecular ion is given with Figure 4.155. The mechanism for confirmation of the m/z 116 ion by Mass Frontier is shown as a fragmentation pathway in Figure 4.156. In conclusion, the generation of the... 

Figure 4.155 Structure Annotated Product Ion Spectrum (Mass Frontier).

Figure 4.156 Product Ion m/z 116 Pathway Confirmation (Mass Frontier).

HighChem (2014) Mass Frontier Operation, http //www.highchem.com/ (accessed 2 November 2014). 

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