386 Fermentation and Biochemical Engineering Handbook Resin Bead Interstitial Liquid Liquid in Rest r Figure 2. Representation of the three phases involved in chromatographic separatic The ratio of individual distribution coefficients is often used as a measure of the possibility of separating two solutes and is called the separation factor, a, or relative retention factor Kdy/k From Table l, the separation factors for acetone-formaldehyde separabil- ity are 0. 49, 0.98 and 1.54 for Dowex 50WX8(H"), Dowex 1X8(CI)and Dowex 1X8(So4)resins, respectively. For comparison purposes, it may be necessary to use the inverse of a, so that the values would be 2.03 and 1.02 for Dowex 50wX8(H)and Dowex 1X8(CI), respectively. When a is less han l, the solute in the numerator will exit the columnfirst. Whenais greater than l, the solute in the denominator will exit the column first386 Fermentation and Biochemical Engineering Handbook -Resin Bead -Interstitial Llquld /iquid In @sin (v,, (Vq) Figure 2. Representation of the three phases involved in chromatographic separation. The ratio of individual distribution coefficients is often used as a measure of the possibility of separating two solutes and is called the separation factor, a, or relative retention factor. From Table 1 , the separation Mors for acetone-formaldehyde separabil￾ity are 0.49, 0.98 and 1.54 for Dowex 50WX8 (H'), Dowex 1X8(C1-) and Dowex 1X8(SOi2) resins, respectively. For comparison purposes, it may be necessary to use the inverse of a, so that the values would be 2.03 and 1.02 for Dowex SOWX8(H') and Dowex 1X8(Cl-), respectively. When a is less than 1 , the solute in the numerator will exit the column first. When a is greater than 1, the solute in the denominator will exit the column first