Page 71 - Instrumental Analysis - Pharm D Clinical- 07-PA403
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Based upon the relative polarities of the mobile and stationary phases
partition chromatography is distinguished into
Normal phase chromatography Reversed phase chromatography
st. ph. is polar (e.g. diol) st. ph. is non-polar (C8, C18)
(dihydroxypropyl bonded phase silica) mob. Ph. is polar
mob. Ph. is org. solvent e.g. methanol, acetonitrile, water, buffers
more polar components elute faster
e.g. n-hexane, chloroform
less polar components elute faster
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Mobile phase Selection
The solvent (mob.ph.) strength depend on:
1) The solvent physical characteristic of the solvent (polarity,
dielectric constant, lypophilicity…)
2) The used st. ph.
St. ph.: bare silica st. ph.: C18
the more lypophilic a mob. Ph.
the more quickly it will cause
The more polar a mob. Ph., migration of a compound
the more quickly it will cause
migration of a compound 52
PrProf. Omayma Abdelrazak Amin
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