Evaluation of thiosemicarbazone derivative as chelating agent for the simultaneous removal and trace determination of Cd(II) and Pb(II) in food and water samples

In the present investigation, prepared N-ethyl-3-carbazolecarbaxaldehyde-3-thiosemicarbazone (ECCT) and employed for the simultaneous removal and determination of trace amounts of Cd(II) and Pb(II) from food and water samples. Cd(II) and Pb(II) gave yellow and orange colored complexes with ECCT in acetate buffer at pH 6.0 with λmax, 380 and 440 nm, respectively. Both complexes were easily extractable into kerosene at 1:1(M:L) composition. It was in accordance with Beer's law in the range of 0.0-12.0 and 0.0-10.0 μg mL−1 with 0.999 and 0.997 correlation coefficient for Cd(II) and Pb(II) complexes, respectively, indicated a good linearity between the two variables. The molar absorptivity and Sandell's sensitivity were found to be 0.740 × 104 L mol−1 cm−1, 1.52 × 10−3 μg cm−2 for Cd(II) and 1.809 × 104 L mol−1 cm−1, 1.15 × 10−3 μg cm−2 for Pb(II). The precision and accuracy of the method was checked for both metal ions by finding the relative standard deviations (n = 8), which were 0.689% and 0.443%, with detection limits of 0.00151 μg L−1 and 0.00264 μg L−1 for Cd(II) and Pb(II), respectively. Further validation using certified reference material, NIST 1568b, resulted in determined concentrations of 0.028 ± 0.253 μg g−1 for Cd(II) and 0.046 ± 0.325 μg g−1 for Pb(II). These determined values agree well with the certified values in the reference materials. The interfering effects of various cations and anions were also studied. The proposed method performance was also evaluated in terms of Student 'T' test and Variance 'F' test, which indicated the significance of the present method parameters, as an inter comparison of the experimental values using ICP-OES.