Application of dispersive liquid-liquid microextraction and high- performance liquid chromatography for the determination of cetrimonium bromide in water samples

A b s t r a c t A simple, rapid and sensitive method for the determination of cetrimonium bromide at trace levels in water samples was developed by combining a dispersive liquid –liquid microextraction (DLLME) technique with high performance liquid chromatography (HPLC-UV). A mixture of extraction solvent and dispersive solvent were rapidly injected into 10.0 mL aqueous sample, and a cloudy solution was formed. After extraction of the analyte into the fine droplets of extractant, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was determined by HPLC-UV. The factors relevant to the microextraction efficiency, such as the kind and volume of extraction and dispersive solvent, and the extraction time were optimized. Under the optimum conditions (extraction solvent: chlorobenzene, volume, 70 μL; dispersive solvent: ethanol, volume, 0.75 mL), the enrichment factor of 200 was obtained. The linear range was 0.005– 100 µg L -1 . The relative standard deviation of 5.9% (n= 5), and detection limit (signal-to-noise ratio of 3) of 0.10 pg mL -1 were obtained.