COMPARATIVE-STUDY OF DIFFERENT SOLID-PHASE EXTRACTION CARTRIDGES IN THE SIMULTANEOUS RP-HPLC ANALYSIS OF MORPHINE AND CODEINE IN BIOLOGICAL-FLUIDS

A comparative study of different Solid-Phase Extraction (SPE) Cartridg es for the extraction and purification of morphine and codeine in plas ma and urine samples is presented. A rapid and sensitive Reversed-Phas e isocratic High-Performance Liquid Chromatographic (RP-HPLC) method h as been developed for the simultaneous determination of morphine and c odeine in plasma and urine samples, using quinine as internal standard . The drugs were extracted from the sample matrices by using the SPE t echnique and a series of cartridges from different manufacturers and w ith different sorbents were tested. The best recovery from plasma was achieved with Alltech C18 cartridges and the best recovery from urine with Bakerbond C18 cartridges. The HPLC analysis was performed with an Adsorbosphere HS C18, ODS, 5 mum, 250 x 4.6 mm I.D., column and UV de tection at 241 nm and it was completed within approximately 10 min. Th e mobile phase was a mixture of methanol-acetonitrile 0.1 M ammonium a cetate (40 : 25 : 35 v/v) and the flow rate was 0.80 ml/min. The detec tion limits were found to be 2.0 ng on-column for morphine and 1.0 ng on-column for codeine.