Retention reproducibility of basic drugs in high-performance liquid chromatography on a silica column with a methanol-high-pH buffer eluent. Changes in selectivity with the age of the stationary phase.
The long-term reproducibility of the separation of basic drugs by high-performance liquid chromatography using a silica column with a methanol-high-pH eluent was examined. The relative capacity factors of specific tertiary amines changed systematically compared with the other drugs on storage of the columns for 1 year. The changes were enhanced on storing the column in mobile phase and were accelerated by prolonged washing with water. A comparison of freshly packed columns suggested that similar changes also occurred with the dry silica on storage. These effects may be a contributor to previously observed batch-to-batch differences in the silica.
Smith
R M
RM
Department of Chemistry, Loughborough University of Technology, Leicestershire, UK.
Westlake
J P
JP
Gill
R
R
Osselton
M D
MD
D002110:Caffeine / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003975:Diazepam / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D000432:Methanol; D009567:Nitrazepam / Q000032:analysis*; D015203:Reproducibility of Results; D012822:Silicon Dioxide
D002110:Caffeine; D012822:Silicon Dioxide; D009567:Nitrazepam; D003975:Diazepam; D000432:Methanol