Scotch tape method like modification of electrode stickers: Bismuth-modified copper-based paper device for simultaneous electrochemical detection of Pb(II) and Cd(II)

Herein we report a simple one-step strategy for surface modification of copper electrode stickers for the fabrication of copper-based paper electrochemical sensing device (Cu-PESD). Taking advantage of conducting adhesive on the copper tape, the scotch tape method is adopted to modify the adhesive surface. Pristine copper electrode stickers fabricated PESD can sense trace metal ions, but the modification of electrodes further improved sensitivity for simultaneous electroanalysis. Bi is selected as a modifier to demonstrate the simple scotch-tape modification strategy. The modified copper electrode stickers with Bi enabled the device to achieve peak resolution, sensitivity, and simultaneous electrochemical detection of Pb(II) and Cd(II). The bismuth-modified copper-based PESD (Bi-Cu-PESD) exhibited the linear range from 0.2 to 12 mg L⁻¹ for simultaneous detection of Pb(II) and Cd(II) ions. The limit of detection was 0.078 mg L⁻¹ and 0.183 mg L⁻¹ for Pb(II) and Cd(II) respectively. Modified electrode stickers were characterized to study the electrode crystallinity, surface morphology, and elemental composition using XRD, SEM, and EDS respectively. The potential of the fabricated PESD was tested by quantifying Pb(II) and Cd(II) ions in the water samples. The electrochemical results were in agreement with the standard AAS method.