Spectrophotometric Determination of CD(II) and Zn(II) with 1,2,3‐Cyclohexanetrione‐1,3‐Dioxime‐2‐Thiosemicarbazone. Simultaneous Determination by first and Second Derivative

1,2,3-Cyclohexanetrione-1,2-dioxime-3-thiosemicarbazone (CTDT), produces coloured complexes with zinc and cadmium ions in basic medium. The yellow colour obtained has been used to develop spectrophotometric methods for zinc and cadmium in the concentration range 1.30-8.50 μg ml−1 of zinc and 1.20-6.50 μg ml−1 of cadmium. A new method for the determination of zinc and cadmium in mixtures is proposed for concentrations between 0.5-6.0 μg ml−1 and 0.8-5.5 μg ml−1 by first derivative spectrophotometry and between 0.5-6.0 μg ml−1 and 0.8-5.5 μg ml−1 by second derivative spectrophotometry.