Ultra-trace levels voltammetric determination of Pb2+ in the presence of Bi3+ at food samples by a Fe3O4@Schiff base Network1 modified glassy carbon electrode

In this research, a highly sensitive electrochemical sensor was developed for the square wave anodic stripping voltammetric determination of Pb2+ at ultra-trace levels. A Glassy carbon electrode was modified with an in-situ electroplated bismuth film and the nanocomposite of a recently synthesized melamine based covalent organic framework (schiff base network1 (SNW1)) and Fe3O4 nanoparticles (Fe3O4@SNW1). The obtained results exhibit clearly that combination of Fe3O4@SNW1 and in-situ electroplated bismuth film enhances the sensitivity of the modified electrode towards Pb2+ remarkably. A Plackett-Burman design was implemented for screening experimental factors to specify the significant variables influencing the sensitivity of the electroanalytical method. Afterward, the effective factors were optimized using Box-Behnken design (BBD). Under optimized conditions, the proposed electrode showed a linear response towards Pb(2+ )in the concentration range of 0.003-0.3 mu mol L-1 with the detection limit of 0.95 nmol L-1. The selectivity of the fabricated electrode towards different ionic species were checked out and no serious interference was observed. At the end, the application of the designed sensor in the determination of Pb2+ at 10 different edible specimens were investigated and the obtained recovery values were in the range of (95.56-106.64%) indicating the successful performance of the designed sensor.

Automated summary

In this study, a highly sensitive electrochemical sensor was developed for the detection of ultra-trace levels of Pb2+. The sensor was modified with an in-situ electroplated bismuth film and a nanocomposite of a recently synthesized melamine based covalent organic framework and Fe3O4 nanoparticles. The combination of Fe3O4@SNW1 and the bismuth film significantly enhanced the sensitivity of the sensor towards Pb2+. The optimized sensor showed a linear response in the concentration range of 0.003-0.3 μmol L-1 with a detection limit of 0.95 nmol L-1. The sensor demonstrated good selectivity towards Pb2+ and was successfully applied for the determination of Pb2+ in different edible specimens.