Linear elution chromatography

Linear elution chromatography, 159 Linear free energy relationships, 274 LInuron, 292... 

Figure 6 shows a chromatogram for linear elution chromatography. The amount of probe injected is set to the amount corresponds to the limit of sensitivity of the detector. The retention time, tR, is the time that the average molecule of probe takes to travel the length of column. And the time is measured to be the midpoint of the symmetrical curve for nonpolar probes and to be a position at which the total area of the asymmetrical curve for polar probes is divided into equal areas. The time, to, is the zero retention time reference measured with a non adsorbing probe such as methane simply to pass through the column space from inlet to out let. 

This model assumes the absence of any disturbance of the acetonitrile adsorption equilibrium by the analyte. This assumption limits the application of this model toward very low analyte concentrations—typical conditions for linear elution chromatography. 

A plot of Eq. 11 for any type of linear elution chromatography describes a hyperbola, as shown in Fig. 9 There is an optimum velocity of the mobile phase for carrying out a separation at which the plate height is a minimiun, and thus, the chromatographic separation is most efficient ... 

Linear elution chromatography used to describe the separation process in partition chromatography where a constant partition or distribution ratio is maintained for a given component throughout the separation. Thus the equilibrium that determines the partition of the solute between the mobile and stationary phases remains constant and the rate at which the solute moves through the column will be proportional to the time it spends in the mobile phase relative to the time spent retained on the stationary phase. 

The h-root method without the introduction of dummy species has been appUed to determine the non-linear conpetitive Langmuir isotherms of nadolol, a three chiral center beta-blocker drug [17]. In this method, the individual isomers of interest, which are often not commercially available, are not required and only very small amount of racemic mixture is needed. This facilitates the determination of isotherms for racemic drugs. This method divides the determination of Langmuir parameters into two parts. The intrinsic affinity coefficients a were obtained from linear elution chromatography, and... 

TABLE 16-14 Expressions for Predictions of Chromatographic Peak Properties in Linear Gradient Elution Chromatography under Trace Conditions with a Small Feed Injection and Inlet Gradient Described by op = opo + pt (Adapted from Refs. A and B). 

Equation 19.8 is the basic retention equation of elution chromatography. It is founded on the assumptions that the distribution isotherm, the plot of q against c at constant temperature, is linear and that equilibrium of the solute between phases is achieved instantaneously throughout the column. 

DL-Leucine, resolution of, 222, 262 Leucine encephalin, 290 LFER, see Linear free energy relationships LH-releasing hormone, 263, 290 Ligate, carbon number of, 153 Ligates, solute binding to, 213 Limiting retention factors, 239 Linear elution adsorption chromatography, 58... 

Experimental and theoretical studies of the behavior of 2,2 -, 2,3 -, 3,3 -, and 4,4 -bipyridines in paper and thin-layer chromato-graphy and of 2,2 - and 4,4 -bipyridines in linear-elution adsorp-tion, - gas, and gas-liquid chromatography have been de-... 

Experimental and theoretical studies of the separation of 1,7- and 1,10-phenanthrolines and some substituted derivatives in linear elution adsorption chromatography,44> 145 thin-layer chromatography,146-148 and liquid-liquid partition chromatography149 have been described. 

Snyder, L. R., Linear Elution Adsorption Chromatography, Advan. 

Cyclohexene is oxidized very slowly in the presence of TS-1 little if any epoxide could be obtained under conditions of rapid oxidation of 1- and 2-alkenes to the corresponding epoxides. This low reactivity has been ascribed to the molecular dimensions of cyclohexene, which cannot enter the channel system of TS-1. Evidence for this suggestion was obtained by elution chromatography when TS-1 was loaded in a chromatographic column and a mixture of cyclohexene and 2-hexene injected, the retention time for cyclohexene was much less than that of linear 2-hexenes, despite the higher boiling point of cyclohexene (Tatsumi et al., 1990a). 

The gas chromatographic method is based on the relation between the differential enthalpy of adsorption at zero coverage and the temperature dependence of the Henry s law constant, kn, as expressed in the form of Equation (4.3). In the low-pressure region, where Henry s law applies, the specific retention volume, Vj, is a linear function of kH (Purnell, 1962 Littlewood, 1970). This relationship makes it possible to make use of elution chromatography since... 

If Eq. (1.15) applies in the chromatographic system used, the elution volume Vr of a sample solute in linear gradient-elution chromatography can be calculated using Eq.(1.36) ... 

Ohashi, S. Tsuji, N. Ueno, Y. Takeshita, M. Muto, M. Elution peak positions of linear phosphates in gradient elution chromatography with an anion-exchange resin. J. Chromatogr. 1970, 50, 349. 

RP gradient elution chromatography with linear gradients can be calculated from Eq. 4 ... 

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