Chiral separation of drugs by micro-LC with cellulose as a stationary phase

Comparison of morphine and hydromorphone analysis on reversed phase columns with different diameters

A comparison of a reversed phase high-performance liquid chromatographic (HPLC) method performed on columns with different internal diameters is reported for the quantitative routine determination of morphine.HCl and hydromorphone.HCl in solutions used for intramuscular injection. The method is based on the ion-pairing properties of sodium dodecyl sulphate (SDS) with alkaloids on a reversed phase LiChrospher RP-18 packing material and UV-detection at 230 nm. The mobile phase consisted of an acetonitrile: water mixture 35:65 (v/v) containing 0.5% (w/v) SDS and 0.4% (v/v) acetic acid. Precision, linearity and limit of detection were compared on the 2, 3 and 4 mm i.d. x 125 mm columns. A robustness test for the determination of hydromorphone.HCl was also evaluated.

Application of the restricted-access precolumn packing material alkyl-diol silica in a column-switching system for the determination of ketoprofen enantiomers in horse plasma

The group of LiChrospher ADS (alkyl-diol silica) sorbents that make part of a unique family of restricted-access materials, have been developed as special packings for precolumns used in the LC-integrated sample processing of biofluids. The advantage of these sorbents lies in the direct injection of untreated biological fluids, that is without sample clean-up, the elimination of the protein matrix with a quantitative recovery together with an on-column enrichment. The present method is based on previous work applying UV detection at 260 nm for ketoprofen determinations. Plasma samples introduced to the ADS precolumn using a 0.1 M phosphate buffer, pH 7.0. After washing with the buffer the ADS column was backflushed with the mobile phase 0.01 M phosphate buffer-6% (v/v) 2-propanol-5 mM octanoic acid at a pH of 5.5, thus transporting the analytes to the chiral-HSA (human serum albumin) (100x4.0 mm) column where the separation of the ketoprofen enantiomers was achieved with a resolution factor of 1.4. The developed column-switching method was fully applicable to plasma injections.