Page 262 - Applied Pharmacognosy

Chiral chromatography

1 Chiral mobile phase additives HPLC
2 Chiral stationary phase
3 Diasteriomeric derivatization

GC has been used with the major limitation of
•Restricted to volatile drugs and volatile derivatives
•High temp. can cause racemization of chiral stationary phases and possibly
the analytes.

I- chiral GC stationary phase
Chiral chromatography is used to separate racemic mixture(enantiomers)
& spatial isomers that are not necessarily optically active e.g. m &p xylenes

Chiral stationary phase is formed of premethylated α or β – cyclodextrins
embeded in a siloxane matrix (35% phenyl , 65% methyl poly siloxane)

Differential interaction between the enantiomers & chiral st.ph. enhance
the resolution

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