Effect of surfactants in the determination of orotic acid in aqueous solutions by sensitized terbium fluorescence

Abstract

The determination of orotic acid in aqueous solutions by sensitized terbium fluorescence has been improved by one order of magnitude by the addition of surfactants to the test solution. In the presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB), linearity is found over approximately four orders of magnitude of orotic acid concentration. Detection limits are close to 1.8 × 10^–9 mol dm^–3 and 9.0 × 10^–10 mol dm^–3 in the presence of non-ionic polyoxyethylene–23 lauryl ether (Brij 35) and cationic CTAB, respectively, compared with 1.0 × 10^–8 mol dm^–3 in the absence of surfactant.