“…They coupled three different columns in series (silica, aminopropylbonded silica, and C 8 -bonded silica) to improve the separation, a move they called "selectivity tuning". Evans and Smith compared the performance of GC, HPLC, and SFC for the separation of hydroxylated dialkyldithiocarbamates with up to three hydroxyl groups, models for drug metabolites (270). SFC compared favorably with the other two techniques.…”