Fabrication of electrospun ZnO nanofiber-modified electrode for the determination of trace Cd(II)

ZnO nanofibers (ZnO NFs) were fabricated by electrospinning a dimethylformamide solution of zinc acetate containing polyvinylpyrrolidone and polymethylmethacrylate binary polymer matrix, followed by calcination. The obtained ZnO NFs are composed of close-packed ZnO nanoparticles of ca.20 nm in diameter. With Nafion acting as adhesive, the ZnO NF coated glassy carbon electrode (ZnO NF/GCE) has been prepared and applied as a new sensing platform for heavy metal determination with square wave stripping voltammetry. The high surface area and the strong affinity to cadmium (Cd) render the ZnO NF/GCE sensitive to Cd ion measurement. The experiment parameters were optimized by the design of orthogonal experiment. Under the optimal conditions, the current response exhibits a good linear relationship with the concentration of Cd(II) ranging from 4.8 × 10−9 to 1.3 × 10−6 mol L−1,with the detection limit of 1.8 × 10−9 mol L−1 (S/N > 3). The developed sensor has been successfully applied for the determination of Cd(II) in water sample. The simultaneous analysis of Cd(II), Pb(II), Cu(II) and Hg(II) has been demonstrated to be feasible.