Catalytic kinetic spectrophotometric determination of trace amounts of copper (II) in biosamples using tween-20 microemulsion as sensitizer

A sensitive and selective kinetic catalytic spectrophotometric method has been developed for the determination of trace amounts of Cu (II) in Tween-20 microemulsion medium. The method is based on the catalytic effect of Cu (11) on the reaction of Nuclear Fast Red with Potassium Periodate in the NH3H2O-NH4Cl butter (pH 10.0). It is obvious that the microemulsion medium has higher sensitivity, better solubility, and stability than that of micelle and aqueous systems, so the new method is recommended for the determination of Cu (11). The reaction was followed spectrophotometrically at 530nm. Calibration lines were in the range of 0.05-20.0 ng mL(-1), and the detection limit was 1.44 x 10(-11) g mL(-1). The optimum operating conditions and the corresponding kinetic parameters of the three systems were presented. The proposed method has been applied to many real samples such as urine and serum samples with satisfactory results. The recoveries were 94.8- 106%, and the relative standard deviation (RSD) was below 4.6%.