Determination of Copper in Water, Vegetables, Foodstuffs and Pharmaceuticals by Direct and Derivative Spectrophotometry

Abstract

The quantification of copper in water, vegetables, foodstuffs, human hair and pharmaceutical samples was determined by a simple more sensitive and selective spectrophotometric method. Cu(II) forms an orange - red color complex with 5-{� -methyl-3-hydroxy benzylidene} rhodanine (5M, 3H-BR), at pH 5.5 in sodium acetate and acetic acid buffer. The maximum absorbance was measured at 430 nm. The Beer's law is obeyed in the range of (0.05 µg -13 µg/mL). The molar absorptivity ( �) and the Sandell's sensitivity of the complex were 0.6027 × 10 4 mol -1 cm -1 and 0.01054 µg cm -2 respectively. First, second and third derivative spectrophotometry were also proposed and employed successfully for the determination of copper in the supra. The performance of the present method was also evaluated in terms of RMSEP, REP and RSD, students t- test. This indicates the greater importance of the method than other methods reported in the literature.