METHODS OF SEPARATION
1
, BASIC PRINCIPLES
• All chromatographic separations rely on the
differences in interaction between analytes
and the two characteristic phases
• Mobile phase: carries/transports the
analytes
• Stationary phase: interacts with the
analytes as they are moving through it.
• Analytes that strongly interact with the
stationary phase are retained longer, thus
elute from the column later than those that
interact weakly with the stationationary
phase.
• Analytes separate into bands
• Analytes are detected at the exit of the
column and their signals recorded
• Plot: chromatogram
2
,• Classification based on the types of mobile and
stationary phases and the kinds of equilibria involved in
the transfer of solutes between phases
• Name based on type of Mobile
3
, Elution
• Elution: washing a
species through a
column by continuous
addition of fresh mobile
phase
• Mobile phase: eluent
• Partition between
mobile and stationary
phase
4