Time resolved mass spectral data

A detailed picture of this process is desired so that the chemical information in the time-resolved mass spectral data can be related to the detonation process. The modeling has provided a picture that has proved useful for the highly interactive process of interpretation... 

Figure 3 (A) Single-column GC analysis result. (B) Selected incompletely resolved heartcuts from A are directed to a second column where improved separation is achieved. Here two heart-cuts are performed. (C) Illustration of multidimensional analysis GC/MS, where the second dimension is a mass spectrum recorded at the mass spectral data acquisition rate. The success of this approach depends on the uniqueness of the mass spectrum at each point in the chromatogram. (D) The comprehensive two-dimensional GC method ideally spreads out the components in a two-dimensional space, according to the characteristics of each of the columns. Each component has a characteristic D and D retention time in the plane.

Brown SD and Harper AM (1993) Multivariate analysis of time-resolved pyrolysis mass spectral data. In Wilkins CL (ed) Computer-Enhanced Analytical Spectroscopy, Vol 4, pp 135-163. New York Plenum Press. 

As early GC peaks elute in a few seconds or less, rapid scanning of the mass range of interest is necessary. Fast scanning also allows partially resolved GC peaks to be sampled several times,peak slicing, to facilitate identification of the individual components (Figure 12.5) provided that the dead volume of the interface is small compared to peak volumes. For the speedy interpretation of spectral data from complex chromatograms a... 

M 52] [P 47] The capillary-in-capillary mixer proved functionality for millisecond time-resolved studies by ESI-MS [133]. The experiments were performed in two modes of operation in a spectral mode with recording of entire mass spectra and in a kinetic mode where the intensity of selected ion signals can be monitored as a function of the average reaction time. This enabled new means of resolving kinetic data, i.e. to measure reliably first-order rate constants up to at least 100 s 1. This performance is four times better than for reported ESI-MS experiments. 

Although the most serious problems affecting the spectral quality of the ion trap as a mass analyzer have been resolved, the perception of the ion trap as a reliable mass analyzer was compromised. Early adopters found the instruments to be unstable and difficult to use. It was not possible to obtain quality full-scan mass data useful for library searches so as to identify unknowns. Quadrupole mass filters at the time were better suited for the analysis of environmental and other dirty matrices, as they were not subject to space charging and ion/molecule reactions. 

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