extraction and determination of cyproheptadine in human urine by dllme-hplc method

novel dispersive liquid-liquid microextraction (dllme), coupled with high performance liquid chromatography with photodiode array detection (hplc-dad) has been applied for the extraction and determination of cyproheptadine (cph), an antihistamine, in human urine samples. in this method, 0.6 ml of acetonitrile (disperser solvent) containing 30 µl of carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5 ml urine sample. after centrifugation, the sedimented phase containing enriched analyte was dissolved in acetonitrile and an aliquot of this solution injected into the hplc system for analysis. development of dllme procedure includes optimization of some important parameters such as kind and volume of extraction and disperser solvent, ph and salt addition. the proposed method has good linearity in the range of 0.02-4.5 µg ml-1 and low detection limit (13.1 ng ml-1). the repeatability of the method, expressed as relative standard deviation was 4.9% (n = 3). this method has also been applied to the analysis of real urine samples with satisfactory relative recoveries in the range of 91.6-101.0%.