Development of an Extractive Spectrophotometric Method for the Determination of Copper(II) in Leafy Vegetable and Pharmaceutical Samples Using 2–acetylpyridine 4–phenyl –3-thiosemicarbazone (APPT)

A highly sensitive extractive spectrophotometric method has been developed for the determination of copper(II) using 2-acetylpyridine-4-phenyl-3-thiosemicarbazone as an analytical reagent. The APPT forms reddish brown complex of copper(II) at a pH range of 3.0-5.5, and the complex was extracted into n-butanol. The Cu(II)-APPT complex shows maximum absorbance at 440 nm, with molar absorptivity and Sandell’s sensitivity being 2.16 x 104 L mol-1cm-1 and 2.94 x 10-3μg cm-2, respectively. The system obeys Beer’s law in the range of 0.2-5.0 mg/L. The regression coefficient of the Beer’s law straight line is 0.338, and the correlation coefficient is 0.96. The detection limit of the method is 0.0065 μg mL-1. Most of the common metal ions generally found associated with copper do not interfere. The repeatability of the method was checked by finding the relative standard deviation. The developed method has been successfully employed for the determination of copper (II) in leafy vegetable and pharmaceutical samples. The method is evaluated by analyzing samples from the Bureau of Analyzed Samples (BCS 233, 266, 216/1, 207, and 179) and by inter-comparison of experimental values using AAS.