Retention slopes

A plot of In n versus L is a straight line whose intercept is In and whose slope is —l/Gt. (For plots on base-10 log paper, the appropriate slope correc tion must be made.) Thus, from a given product sample of known shiny density and retention time it is possible to obtain the nucleation rate and growth rate for the conditions tested if the sample satisfies the assumptions of the derivation and yields a straight hne. A number of derived relations which describe the nucleation rate, size distribution, and average properties are summarized in Table 18-5. 

It is seen that by taking a mean value for the slope, there is very little divergence between the calculated and experimental values. Consequently, the methylene groups can, indeed, be taken as a reference group for assessing the effect of molecular structure on solute retention. The concept will now be applied to a simple n-alkanes series as discussed above, the data for which was obtained on the stationary phase n-heptadecane. 

Thus, if the slope and intercept of the curve relating the reciprocal of the corrected retention volume to the concentration of the moderator are (p) and (tj)) respectively. 

Higher concentrations of solute move through the system more rapidly, thus reducing the retention time of the peak maximum which produces a peak with a sharp front and a sloping tail. 

Higher concentrations of solute move through the system more slowly displacing the peak maximum to a later retention time and, thus, a peak is produced with a sloping front and a sharp back. 

Fig. 17. A schematic of the alkane line obtained by inverse gas chromatography (IGC) measurements. The relative retention volume of carrier gas required to elute a series of alkane probe gases is plotted against the molar area of the probe times the. square root of its surface tension. The slope of the plot is yielding the dispersion component of the surface energy of...

In evaluating the effect of these errors, it must be remembered that these values are errors in retention time. The error in molecular weight will depend on the slope of the calibration curve, but will usually be considerably larger. 

Note that the initial slope of the adsorption isotherm can be easily obtained from the knowledge of the retention time associated to a small injection performed on a column, as this retention time is given by t = t icj where... 

Ethoxy Naphthalene Mean Retention Volume 4.93 ml 10 k Slope-0.070 ml/C 1.44%/C... 

The GPCV2 equations were developed for conventional log(MW) vs. retention volume calibrations. When used in conjunction with a universal calibration, the slope term (Do) must be corrected for the different molecular size/weignt relationships of the calibrants and the samples as derived in the following equations. To understand this correction, consider the conventional calibration curve that could be created from the universal calibration data. 

In Fig. 34.34 the first three local PCs with the associated eigenvalues are given for four retention time regions (a) a zero component region (Fig. 34.34a), (b) selective chromatographic regions at the up-slope side (Fig. 34.34b), (c) and at the... 

Retaining Walls, Sea Walls, etc or carefully selected Planted Trees on slopes, shores and coasts for Soil Retention. 

It is also quite interesting that lipid model 4.0 may be used to obtain alkane partition coefficients at high-throughput speeds, as suggested by Faller and Wohnsland [509,554], It is also interesting to note that since our Pe are corrected for membrane retention, the slope in Fig. 7.11 corresponding to the dashed line (our data) is 1.0, whereas the data not corrected for retention (solid line) show a lesser slope. This may not matter if the objective is to obtain alkane-water log Kp values at high speeds. 

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