A specific and precise High-performance liquid chromatography (HPLC) method with diode array detection (DAD) has been sophisticated for tetramethrin determination in environmental water samples. Water samples were collected from two governorates in Upper Egypt: Assiut and Qena. Extraction of tetramethrin from water samples was carried out using liquid-liquid extraction method before the injection of analyte into HPLC-DAD system. The best separation method has been achieved on the Supelcosil TM LC-18-DB column (4.6* 250mm), particle size 5μm, with mobile phase methanol: water (78:22,v/v) at temperature of 30O°C and at a flow rate of 0.8mL/min. The detection wavelength of the detector was set at 220nm. Calibration curves obtained over the concentration range of 10-100µg mL -1 were linear. The accuracy ranged from 99.44% to 102.07%. The suggested study showed that most of samples do not contain tetramethrin residues, while few samples contain tetramethrin residues.

InstrumentationHPLC Instrument: The HPLC system used was Hitachi L-2000 series (Japan), equipped with a Model L-2130 pump, an L injection loop and a UV-Vis detector L2420. The separation was carried out in a Abstract This paper describes an enhanced High-performance liquid chromatography (HPLC) method for the analysis of miconazole in water samples. In this study, determination of miconazole has been carried out according to standard method for water and wastewater analysis. Samples of collected water were agriculture stream water, River Nile (Surface water samples) water and Hospital wastewater samples from El-gharbia governorate in Egypt. Miconazole was extracted by liquid-liquid extraction and analyzed by HPLC. The chromatographic separation was performed using a Phenomenex C8 column, flow rate of 0.8mL/min, and UV detection at 220nm. The optimized HPLC system was achieved using mobile phase composition containing methanol: water (85:15v/v). The intra-day and interday precisions were lower than 0.58 while the accuracy ranged from 99.06% to 101.53%. Finally, liquid-liquid phase extraction in combination with HPLC is a sensitive and effective method for the determination of Miconazole Nitrate in water samples. Miconazole was observed in some agricultural streams and waste water samples of El-gharbia governorate hospitals.