TLS Online TPP Program

#Id: 2784

#Unit 13. Methods in Biology

Retention factor (k) is simply the additional time that the analyte takes to elute from the column relative to an unretained or excluded analyte that does not interact with the stationary phase and which, by definition, has a k value of 0. Thus

TLS Online TPP Program

#Id: 2785

#Unit 13. Methods in Biology

The ratio VS/VM is referred to as the volumetric phase ratio, b. Hence:

TLS Online TPP Program

#Id: 2786

#Unit 13. Methods in Biology

Chromatography columns are considered to consist of a number of adjacent zones in each of which there is sufficient space for an analyte to completely equilibrate between the two phases, Each zone is called a theoretical plate (having no N).

TLS Online TPP Program

#Id: 2787

#Unit 13. Methods in Biology

The length of column containing one theoretical plate is referred to as the plate height, H, which has units of length normally in micrometers.

TLS Online TPP Program

#Id: 2788

#Unit 13. Methods in Biology

Therefore, that k is related to the distribution coefficient. Since amount and concentration are related by volume by

TLS Online TPP Program

#Id: 2789

#Unit 13. Methods in Biology

The second component is the time the stationary phase retains the analyte, referred to as the adjusted retention time, t’R.