•Besides C18 can have C8, C4,
C3, C2,
C1 plus functionalities like cyano (-C2H4CN),
amino (-C2H4NH2),
diol (-C3H6O-CH2-CHOHCH2OH)
•Each has different
polarity
•Can also do Ion Pair
Chromatography or Paired-Ion Chromatography – type of RP-HPLC
used to separate ionic species
•Still partition chrom. but use a reagent like a
quaternary ammonium salt (C4H9)4N+ to pair with analyte ions to
separate by RP