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Nonretained peak

For isocratic LC, the solute does not need to fully elute from the second-dimension column prior to the next sampling period. This is illustrated in Fig. 6.4, where it is shown that more than one sample can be resident in the column at one time. Using the chromatograms shown in Fig. 6.5, which show the effect of various injection volumes that will be discussed later, it is not necessary to wait for the full 2 min of sampling time. This significantly helps to speed up the sampling process and is most useful for SEC, where short elution time ranges are typically found and short times between the injection and nonretained peaks are typical of column operation. [Pg.137]

Equation 10.1 shows that R is a measure of the retardation or slowing of the zone or peak with respect to mobile phase velocity. A peak that experiences no retardation because its solute does not partition into the stationary phase (R = 1) is termed a nonretained peak or void peak such a peak travels at mobile phase velocity v. Solute retained to some extent by the stationary phase migrates as a retained peak, for which R< 1. (The smaller R, the greater the retention.) Because of its key role in specifying retention, R is termed the retention ratio. [Pg.233]

Show that v for a nonretained peak in a GC column equals v0j. The distance-average velocity in a column can be expressed by... [Pg.248]

Other phenomena besides conformational processes can also lead to multizoning effects with polypeptides and proteins when they interact with adsorptive HPLC sorbents. The so-called split peak effect is probably the easiest of these phenomena to be identified and steps taken to remedy. The split peak effect is very often seen in HP-BAC, RP-HPLC, and HP-HIC and to a lesser extent in the HP-IEX of proteins.325-327 This effect is manifested by the presence of a weakly retained (or occasionally as a nonretained peak) and a more strongly retained peak with the bound-to-free ratio between the weakly retained to strongly retained species dependent on the diffusion and adsorption kinetics. An extreme case of the split peak effect involves the weakly interacting component elution in or near to the column breakthrough volume. In this case, the amount of protein in the breakthrough zone is influenced by the nominal pore diameter and ligand density of the sorbent, the flow rate, and the injection volume. This effect can be circumvented by... [Pg.168]

Several theoretical models were constructed to describe the chromatographic process in the frontal 116.191 and the zonal elution mode 20. The conventional method of obtaining the kinetic parameters consists in fitting the model to the experimental breakthrough curves. Another method based on the split-peak effect is a direct measurement of the apparent association rate constant (7,211. Because of the slow adsorption process, a fraction of the solute injected as a pulse into the immunochromatographic column is eluted as a nonretained peak. This behavior is observed at high flow rates, with very short or low-capacity columns 121—251. [Pg.346]

The plate number calculated from a nonretained peak is a measure of the column... [Pg.29]

It is the adjusted retention volume which is directly proportional to the thermodynamic distribution constant and therefore the parameter often used in theoretical equations. In essence it is the retention time measured from the nonretained peak (air or methane) as was shown in Figure 1.5. [Pg.23]

The retention ratio R of particles is defined as the ratio of the elution time for the particles, to that for a nonretained peak, tQf as in usual chromatography, and its expression was obtained by Hovingh et al. ... [Pg.293]


See other pages where Nonretained peak is mentioned: [Pg.362]    [Pg.52]    [Pg.234]    [Pg.234]    [Pg.239]    [Pg.339]    [Pg.246]    [Pg.303]    [Pg.364]    [Pg.833]    [Pg.190]    [Pg.120]    [Pg.127]    [Pg.369]    [Pg.369]    [Pg.761]   
See also in sourсe #XX -- [ Pg.216 , Pg.233 , Pg.234 , Pg.239 ]




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