2-(3- indolyl) 4,5 di phynyl imidazole.(IDPI) was used as a complexing agent in cloud point extraction for the first time and applied for selective pre-concentration of trace amounts of cadmium. The method is based on the extraction of cadmium at pH= 7.0 by using non-ionic surfactant Triton-X114 and 2-(3- indolyl) 4,5 di phynyl imidazole. (IDPI) as a chelating agent. The adopted concentrations for IDPI, Triton X-114 and HNO3, bath temperature were optimized, The response are linear over concentration range of 8.0-90 (ng mL-1) for Cd2+ and RSD % (n =5) 1.8 for Cd2+, Detection limits (3SDb/m, n =10, m = slope of calibration) of 2.8 (ng.mL-1) for Cd2+ respectively. The enrichment factors was 33 for Cd2+. the preconcentration factors was 39 for Cd2+ respectively. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method was successfully applied to the ultra-trace determination of cadmium in real and water samples. تفاصيل المقالة