Determination of water-soluble UV-filters in sunscreen sprays by liquid chromatography

Liquid chromatography was used for the determination of the three most used water-soluble UV filters, benzophenone-4 (BZ4), terephthalylidene dicamphor sulfonic acid (TDS), and phenylbenzimidazole sulphonic acid (PBS), in aqueous sunscreen sprays. A C18 stationary phase and an isocratic mobile phase of EtOH–20 mM sodium acetate buffer of pH 4.6 (30:70, v/v) were used at a flow-rate of 0.5 ml min−1. Mobile phase was also used as solvent for samples and standards. UV detection was at 313 nm. The analytical run took 5.5 min. The limits of detection were 0.5, 0.9 and 2 μg ml−1 for BZ4, TDS and PBS, respectively. The proposed method does not involve highly toxic solvents.