Optimasi Kompleksasi Cd(II) dengan Natrium Dietilditiokarbamat dan Ekstraksi Kloroform Berbasis Spektrofotometri UV-Vis

Abstract

Determination of the toxic metal ion Cd(II) through complex formation and solvent extraction requires evaluation of operating conditions and the effects of interfering ions. This study aimed to evaluate the conditions for complex formation between Cd(II) and diethyldithiocarbamate (DDTC), as well as the effect of Mo(VI) on the analytical response, using UV–Vis spectrophotometry. The parameters examined included absorption wavelength, pH, shaking time, standing time, and Cd(II) concentration. The effect of varying Mo(VI) concentrations was tested at a fixed Cd(II) concentration of 25 ppm. Spectral scanning was performed over the range of 300–600 nm. The results showed that, among the selected data points analyzed, the highest absorbance was recorded at 335 nm, with a value of 0.35928. When pH was varied, the highest mean absorbance of 0.64396 was obtained at pH 5, whereas when shaking time was varied, the highest value of 0.314765 was obtained at 15 min. In the standing time profile, the highest absorbance of 0.448885 was recorded at 50 min. Calibration of Cd(II) over the range of 10–40 ppm yielded the regression equation y = 0.0189x + 0.0397 with R² = 0.9989. Increasing the Mo(VI) concentration from 5 to 25 ppm increased absorbance from 0.532899 to 0.696875, compared with the reference absorbance of 0.5198 for Cd(II) without added Mo(VI). These findings indicate that Mo(VI) affects the analytical response under the test conditions and needs to be considered when evaluating method selectivity. This study provides a preliminary basis for establishing operating conditions for Cd(II)–DDTC complexation and extraction. However, the wavelength profile, selectivity, and analytical performance require further confirmation before the method is applied to real samples.