Plot of capacity factors

Figure 8. Plot of capacity factors for combination of DB-1 and DB-624 stationary phases.

Figure 1. Plots of capacity factors k vs /5-CD concentration for methylphenobarbital enantiomers. Stationary phase 10 nm LiChrosorb RP-18 mobile phase 20% ethanol-buffer solution of pH=2.0 containing various /9-CD concentrations temperature 25 "C. (Reprinted with permission from ref. 26. Copyright 1986 Marcel Dekker.)...

Fig. 9 Plot of capacity factor term versus k for the modified fundamental resolution equation.

Fig. 7.3. Van t Hoff plots of capacity factors. Chromatographic conditions column, Partisil 1025 ODS (250 mmX4.6 mm I.D.) mobile phase, 0.05 M KH2PO4 flow rate, 1 ml/min temperature, 25° C detection, UV at 254 nm. Reproduced from Horvath et al. (1976), with permission.

Caude and co workers [722] used Pirkle-type tyrosine linked dinitrobenzene stationary phases (X = 254 nm) to study the resolution of the enantiomers of alkyl-AT-arylsulfinamoyl esters. To optimize the separation, various ratios of 98/8 hexane/ethanol and 50/50 hexane/chloroform were mixed to form a ternary eluent An informative plot of capacity factor and separation factor is presented for one compound and a table of retention and selectivity is given for various hexane/polar solvent mixtures (polar solvent=ethanol, IPA, chloroform, or dichloromethane). 

In figure 1.8 the theoretical peak capacities are given for some typical ranges of capacity factors as a function of the number of plates. The resolution values were taken to be equal to one. In the logarithmic plot of figure 1.8 a straight line is obtained with a slope of 1/2. A typical packed column with 5000 plates turns out to yield a peak capacity between 17 (case a) and about 50 (case c). An open column with 200,000 plates may accommodate 100 peaks with capacity factors between 0.2 and 2 (case a). 

Fig. 11.2. Plots of logarithms of capacity factors, log , against volume percent of methanol in eluent in 7 HPLC systems for a pyrazine derivative analyte. A-A ODS, pH 2.4 A - A ODS. pH 7.4 - ODS. pH 7.4, n-octanol, /i-decylamine - Suplex pKb-lOO, pH 2.4 c-c Suplex pKb-lOO, pH 7.4 Unisphere-PBD, pH 2.4 - Unispbere-PBD, pH 1 1.5. (Reprinted with permission from R. Garni-Yilinkou and R. Kaliszan, Pol. J. Pharmacol. Pharm. 44 (1992) 515.)...

Entrainment flooding is the most common. Among different methods the correlation proposed by Fair (1961) found a wide acceptance. Fig. 16.7 presents a generalised plot in terms of capacity factor Cp that includes the flooding velocity u j... 

Figure 9-17 plots flood capacity versus flow parameter. The FP values of 0.4-0.7 are estimated by Kister, el al. [136] in absence of data. The plots show that for low and moderate pressures the flood capacity factor versus FP correlates the effects of liquid rate and pressure on the optimized tray capacity [136]. At higher pressures an additional effect of pressure on capacity shows a decline of optimized tray capacity. 

The capacity factor for the system, therefore, is a linear function of the relative retentlvity on either column and a plot... 

Many chromatographic systems show linear relationships between the logarithm of the capacity factor and the reciprocal of the column temperature (van t Hoff plots) [255,258-261]. In thermodynamic terms the interaction of the solute with the stationary phase can be described by... 

Figure 1.2 Plot of theoretical plate nunber (n), effective plate nunber (N) and separation nuober (SN) against the capacity factor for an open tubular column operated under isothermal conditions. (Reproduced with permission from ref. 41. Copyright Friedr. Vieweg Sohn).

Ten columns of the 24 available in a cartridge were employed to analyze all compounds in duplicate. Uracil, was employed as a dead volume marker (tO) needed for the evaluation of retention factor [k = (tr - t0)/t0]. Two additional columns were used for simultaneous analysis of the unknown. Values for the log of the capacity factor k were calculated for every compound at each percent organic content of the mobile phase log k = log [(tr - t0)/t0. For each compound, a plot of log k versus percent acetonitrile was used to calculate log k w (log k at 0% acetonitrile). 

Since k is proportional to K, mathematical treatments appropriate for equilibrium constants apply to the capacity factor k. Plots of log k vs. 1 IT where T is in degrees Kelvin for any given molecule should yield a straight line over reasonable ranges of temperature. 

The plots of log k vs. log P w and the plots of log k (v) vs. log k (z) were studied for seven cephalosporins. A linear relationship was obtained in micellar solution and in microemulsion solution (Tables 3 and 4). The results obtained indicate that the capacity factor determined by EKC could be used both as parameter to characterize the partition behavior of drugs in ME and MC and as hydrophobic parameter instead of log Pow. k appears to be an evident parameter, and it shows a better diversification than P w. In the 1-octanol/water system, we did not found high values of the partition coefficients. In contrast, the ME systems used provide a better characterization of the drugs according to their hydrophilic/lipophilic properties. 

Figure 4 Plots of the Logarithmic Capacity Factor, In k, versus the Volume Fraction of the Organic Solvent, ip, for the 14-mer Peptide, Bombesinl46 3-1,...

Figure 13 Plots of the Capacity Factors, K, of the Paracelsin A-D as a Function of the n-Alkyl Length of Different RPC Silica Sorbents of Constant Ligand Density in H20/MeOH/MeCN (22 39 39) 1201ab...

An important thermodynamic parameter in cooling tower calculations is the ratio of the thermal capacity of the water stream to that of the sir stream. This parameter is referred to as, the tower capacity factor. It is shown that when air or water efficiency, are plotted against the capacity factor test points for a given tower are found to lie on a single smooth curve. The correlation is obtained, irrespective of whether the equipment is used as a water cooler or air cooler, and irrespective of the temperature levels, temperature ranges and barometric pressures. The paper also shows that when a specified amount of heat has to be rejected into a specified air stream, optimum performance giving the lowest average water temperature is obtained when the water flow rate is chosen so that its thermal capacity is equal to the potential thermal capacity of the air stream. 13 refs, cited. 

Briefly, the method involves determining the capacity factors (retention time corrected for an unretained substance) for a suitable set of reference substances (having known K(k values) using RP-HPLC. The relationship between the capacity factors and Kol for the reference or calibration compounds is determined from regression analysis of a log-log plot of the two properties. The capacity factors of compounds having unknown Koc values then are determined using the identical experimental conditions, and Koc values then are calculated from the regression expression. 

Figure 3.6 Variation of retention with the composition of the stationary phase in GLC. Stationary phase styrene-butadiene polymer blends and copolymers, the butadiene fraction is plotted on the horizontal axis, (a) Specific retention volumes for three n-alkanes and benzene. V is proportional to the capacity factor, (b) the retention index for benzene. The solid line is calculated from the straight lines in figure 3.6a. The circles (polymer blends) and triangles (copolymers) represent experimental data. Figure taken from ref. [310], Reprinted with permission.

Figure 4.11 Calculated characteristics for optimum chromatograms (r = 1) containing 10 equally resolved peaks as a function of the separation factor S. Plotted on a logarithmic scale are the capacity factor of last peak (1 +k eqn.4.46), the required number of plates (Afne eqn.4.47), the required analysis time under conditions of constant flow rate and particle diameter (rne f>(ji eqn.4.48), and required analysis time under conditions of constant pressure drop fne p eqn.4.49). For explanation see text.

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