Retardation factor

fully developed

The extent to which substances move on the thin layer plate in a particular mobile phase is a characteristic of the substance is known as the Rf (retardation factor).

The Rf for each spot can be calculated as shown below.

The position of spotting is shown by the line just up from the bottom of the plate.

Rf values are between 0 and 1.

Rf	=	distance spot travels from spotting position
		distance solvent front travels from spotting position

Think about:
Rf(blue spot) is

Rf(yellow spot).

Dr Sheila Woodgate
© The University of Auckland 2002