Residence time line broadening

The signal intensity and line shape can be significantly affected in continuous-flow detection and, in the case of CE, additional broadening is produced by the electrophoretic current. The amount of time that a nucleus spends in the NMR flow cell or the residence time, t, is related to the observe volume and the applied flow rate, F,... 

Table 1.1 Variation of residence time and line broadening as a function of detection cell volume and flow rate in continuous-flow NMR spectroscopy.

Bypassing the reactor showed that the broadening of the pulse caused by the feed and effluent lines was negligible. Hence, the normalized pulse response is the residence time distribution (RTD) of the recycle reactor. 

For the localized motion, data were collected only at room temperature (see table 2) the width of the quasi-elastic line was too small to obtain an accurate value for t (12n). Qualitatively, the residence time at the 12n site seems to be longer in these two hydrides than in the LaNi Mn and LaNi 0 5 Q-dependences of the linewidth of the diffusive component is very weak (figure 7). For the LaNi Al hydride at 300K, the width of the quasi-elastic line is at the limit of the measurable broadening. This is in agreement with the results from an NMR investigation (13) ... 

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