Voltammetry of nanoparticle-coupled imine linkage-based receptors for sensing of Al(III) and Co(II) ions

Zinc oxide nanoparticle-coupled imine linkage-based receptors ( T4 , T5 and T6) were studied for their voltammetric characteristics. T4 and T5 having electron withdrawing and electron donating substituents at meta position of the imine linkage showed prominent cathodic (reduction of imine group) peaks at −0.930 and −1.850 V, respectively, while T6 (without any substituent) showed a cathodic peak at −1.220 V. Voltammograms of the receptors indicated that T4 and T5 responded quantitatively for aluminium ions, while T6 responded for cobalt ions. All the three receptors exhibited linear dynamic concentration ranges between 0.1 and 0.42 µM with regression coefficients ≥0.98. Calibration curves for the determination of aluminium and cobalt ions based on DPV data are reported and supported with potentiometric studies. Energy minimization studies using Gaussian 03W software also supported stability of the complexes. The proposed analytical method has been validated with complexometric method for metal detection in real-time samples.