Voltammetric simultaneous ion flux measurements platform for Cu²⁺, Pb²⁺ and Hg²⁺ near rice root surface: Utilizing carbon nitride heterojunction film modified carbon fiber microelectrode

© 2017 Elsevier B.V. Developing an available analysis platform for simultaneous heavy metal ion flux measurement at trace level is urgent for understanding the mechanisms of phytoremediation. Herein, oxygenous functionalized carbon nitride nanosheets assembled porous films on multi-walled carbon nanotube formed nano frameworks was firstly prepared on a carbon fiber disk microelectrode by an advanced drop-casting method. The as-prepared electrode shows low detection limit (The 1.0 × 10−13 mol L−1 for Cu2+, 1.8 × 10−11 mol L−1 for Pb2+ and 8.0 × 10−12 mol L−1 for Hg2+), acceptable linear range (6.6 × 10−12 ∼ 8.5 × 10−6 mol L−1 for Cu2+, 8.1 × 10−10 ∼ 8.5 × 10−6 mol L−1 for Pb2+ and 2.2 × 10−11 ∼ 8.5 × 10−6 mol L−1 for Hg2+) and fine selectivity in simultaneous determination. The improved accumulation ability of modifier is attributed to improved conductivity and the porous morphology of the film, which may improve useful rate of the chelation groups. Based on the as-prepared electrode and a stepper motor, the voltammetric platform for simultaneous heavy metal ion flux measurement at trace level is fabricated for the first time. This platform can be utilized for mechanism investigation of simultaneous metal uptake on the surface of rice roots at trace level