Theoretical
plate is a term coined by Martin &
Synge. It is based on a study in
which they imagined that chromatographic columns were analogous to distillation columns and made up or numerous discrete but connected narrow
layers or plates. Movement of the
solute down the column then could be treated as a stepwise transfer.
Theoretical
plates (N) measure how
efficiently a column can separate a mixture into its components. This efficiency is based on the retention time
of the components and the width
of the peaks.