Application of cloud point methodology to the determination of nitroanilines in natural water

We developed a methodology based on cloud point extraction (CPE) for the determination of three nitroanilines, p-nitroaniline (PNAL), m-nitroaniline (MNAL), and o-nitroaniline (ONAL). The CPE methodology was coupled with high performance liquid chromatography determinations. Tergitol 15-S-7, an environmentally friendly nonionic surfactant, was employed as the surfactant. To obtain the optimum extraction efficiency, several experimental factors were investigated, including sample pH, salt concentration, surfactant concentration, equilibration temperature, and incubation time. Under the optimized experimental conditions, the linear ranges were 0.06–1, 0.03–1, and 0.01–1 μg mL for PNAL, MNAL, and ONAL, respectively. The limits of detection (LOD) for PNAL, MNAL, and ONAL were 0.013, 0.005, and 0.002 μg mL with the intraday and interday relative standard deviations less than 3.1% and 6.5%. The present method proved to be simple, green, rapid, sensitive, and competitive when used for the determination of nitroanilines in water samples, and the accuracy was assessed through recovery experiments.