Abstract
The determination of 3-hydroxyquinine in urine and plasma samples is described. Extraction was performed using a mixture of toluene–butanol (75:25, v/v), followed by back-extraction into the mobile phase, which consisted of 0.1
M phosphate buffer, acetonitrile, tetrahydrofuran and triethylamine. A reversed-phase liquid chromatography system with fluorescence detection and a CT-sil C
18 column were used. The within-assay coefficient of variation of the method was 2% at the higher concentration values in plasma, 2.95 μ
M, 4% at 227 n
M and 9% at the lower limit of quantitation, 4.5 n
M. In urine, the coefficient of variation was 11% at the lower concentration, 227 n
M and was 3% at 56.8 μ
M. The between-assay coefficient of variation was 4% at the low concentration (5.1 n
M) in plasma, 2% at 276.8 n
M and 3% at 1.97 μ
M. In urine, the between assay coefficient of variation was 4% at 204.6 n
M, 3% at 5.12 μ
M and 2% at 56.8 μ
M.