The Mechanism of Chromatographic Retention - Mixed Phases > Page 23

Purnell employed three procedure to examine the effect of binary mixtures as stationary phases on solute retention; first the two fractions were mixed, coated on some support, and packed into the column; second each of the two fractions were coated on separate aliquots of support and then the coated supports mixed and packed in a column; third each fraction was coated on a support and the appropriate quantity packed into separate columns and the columns joined in series. The results demonstrated that all three columns gave exactly the same corrected retention volume for a given solute. These simple experiments were of fundamental importance and are depicted in figure 10.


Purnell experimentally demonstrated that V'1 = V'2 = V'3


Figure 10 Alternative Methods for Combining Volume Fractions of Stationary Phase in GC