SIMULTANEOUS SOLID-PHASE EXTRACTION AND CHROMATOGRAPHIC ANALYSIS OF MORPHINE AND HYDROMORPHONE IN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

High-performance liquid chromatography has become an important analytical tool for the quantitation of opioid drugs. Using solid-phase extraction and coulometric electrochemical detection. we have developed a chromatographic method for the simultaneous measurement of morphine and hydromorphone which is both sensitive and specific. Using 1 ml of plasma, intra-assay and inter-assay data show that the detection limit for accurate quantitation of these compounds is about 1.2 ng/ml (coefficient of variation 11.6%) for morphine and 2.5 ng/ml (coefficient of variation 10.5%) for hydromorphone. The method is simple and readily adaptable to most pharmacokinetic studies and toxic screens involving these drugs.