UV-Spectrophotometric Determination of Roxithromycin in Environmental Water Samples with Separation by Solvent Floatation

Roxithromycin in environmental water was separated and enriched by solvent floatation, and determined by UV spectrophotometry. Floatation was carried out in a K2HPO4 solution of pH 9.0 with isopropanol as floatation solvent and by passing N2-gas through the solution at the rate of 15 mL·min-1 for 30 min. Linear relationship between values of absorbance and mass concentration of roxithromycin were obtained in the range of 8.2-40.2 mg·L-1, with detection limit (3S/N) of 0.26 mg·L-1. In testing for recovery by addition of standard roxithromycin solution at 3 concentration levels to samples of river and lake water, values of average recovery more than 90% were obtained.