Colorimetric Detection of Copper(II) Ions Using Schiff-Base Derivatives

Two new Schiff base derivatives N,N-dimethyl-4-((2-(phenylthio) phenyl)imino)propenyl)aniline (CSP) and 2-(4-(dimethylamino)phenyl) allylidene) amino)benzenethiol (CSH) were synthesized. Sensing mechanism of the sensors was investigated using UV-Vis spectroscopy in the presence of various metal ions. The sensorCSPshows high sensitivity and selectivity to Cu(2+)over a wide range of other metal ions in acetonitrile (ACN)/water (H2O) (v/v 2 : 1). The sensorCSPcan detect Cu(2+)ions by color change from yellow to pink. The complex stoichiometry between the sensor,CSP, and Cu(2+)was found to be 2 : 1 and the binding constant was calculated to be 2.40 x 10(10) M-2. The absorbance detection limit ofCSPfor Cu(2+)was determined as 2.85 x 10(-6) M. The sensor,CSP, was also applied to real samples successfully.