Voltammetric monitoring of Cd (II) by nano-TiO2 modified carbon paste electrode sensitized using 1,2-bis-[o-aminophenyl thio] ethane as a new ion receptor

The objective of the work ahead is presentation of a new carbon paste electrode (CPE) modified by TiO2 nanoparticles (TiO2NPs) and 1,2-bis-[o-aminophenyl thio] ethane (APTE) ligand as a selective cation receptor for determination of the Cd (II) ions using differential pulse anodic stripping voltammetry (DPASV). The electrode shows an excellent tendency to Cd (II) ions in presence of some interfering species. Under the optimum conditions, a linear calibration curve was obtained in the concentration range of 2.9 nM to 4.6 μM with a correlation coefficient of 0.9969 in the anodic potential of 0.54 (V vs. Ag/AgCl). The metal detection limit was 2.0 nM after 10 min preconcentration (S/N = 3). The sensor shows high applicability in solutions with the optimal pH of 9.0 adjusted by 0.1 M phosphate buffer as supporting electrolyte and open circuit accumulation optimum time of 10 min. The stability of the modified electrode was studied in the period of 2 months week by week. The results showed that for a series of several determinations of Cd (II) at 25 μM relative standard deviations (RSDs) are below 3.4% for modified CPEs. Eventually, the electrode was successfully used for determination of Cd (II) in tap water, Livergol herbal medicine and garden soil aqueous samples.