Improved RP-HPLC determination of quinine in plasma and whole blood stored on filter paper

Analysis of quinine in plasma and whole blood samples dried on filter paper is described. Sample preparation involves liquid extraction of plasma and whole blood from the filter paper and subsequent solid-phase extraction using CS Bond Elut cartridges. A reverse-phase liquid chromatography system with UV detection and fluorescence detection was used. The analytical characteristics of the method are reported, with a quantification limit of 0.1 mug mL(-1) and within an assay coefficient of variation of 5.6-8.4% in plasma and 6.5-12% in whole blood. Representative chromatograms are shown as a function of time for samples from human subjects after ingestion of a single 400-mg dose of quinine sulphate. Quinidine, dihydroquinine and metabolites are well separated from quinine with a resolution of above 1 (Rs. > 1). Copyright (C) 2000 John Wiley & Sons, Ltd.