Analytical Sciences

Combination of Microporous Hollow Carbon Spheres and Nafion for the Individual Metal-free Stripping Detection of Pb²⁺ and Cd²⁺

Xiangheng NIU,*,** Hongwei ZHANG,*** Meihua YU,*** Hongli ZHAO,* Minbo LAN,* and Chengzhong YU***

*Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai 200237, China
**Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China
***Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane QLD 4072, Australia

Here, the combination of Nafion with microporous hollow carbon spheres (MHCS) is first proposed to fabricate a disposable metal-free electrode for heavy metal stripping sensing. The MHCS–Nafion composite film electrode is prepared by drop-casting a mixture of MHCS and Nafion onto the lab-made screen-printed carbon electrode (SPCE^*). Results demonstrate that the interfusion of MHCS into Nafion offers enhanced performance for the electro-enrichment and stripping of lead and cadmium over the only Nafion film: 1) abundant MHCS immobilized on the electrode surface serve as effective nucleation sites for metal ion reduction; 2) the mixing of MHCS into Nafion enlarges the active surface of negative-charged Nafion for the electrostatic adsorption of metal cations. The proposed MHCS–Nafion/SPCE^* provides linear responses for Pb²⁺ and Cd²⁺ in the range of 2 – 200 μg/L, with a detection limit of 1.37 and 1.63 μg/L, respectively. Practical applications of the sensor in water sample detection with good accuracy have also been confirmed.

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