Graphitic Carbon Nitride/Ni Doped Copper Hydroxide Nanocomposite Based Electrochemical Sensor for Trace Level Detection of Ponceau 4R Food Colorant

In this work, a new nanocomposite of nickel-doped copper hydroxide nanoparticles/graphitic carbon nitride was prepared and used to modify the surface of glassy carbon electrode (Ni:Cu(OH) 2 /g-C 3 N 4 /GCE) without any binder. The modified electrode was employed to determine Ponceau 4 R food colorant in aqueous solution by square wave voltammetry. The newly prepared nanocomposite was characterized by Fourier transform infrared spectroscopy, ultraviolet-visible absorption spectrophotometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Under optimal experimental conditions, Ni:Cu(OH) 2 /g-C 3 N 4 /GCE presented a linear response to Ponceau 4 R oxidation in the concentration range from 0.1 to 10 μ M with a detection limit of 56 nM and sensitivity of 2.273 μ A μ M −1 . Besides, acceptable selectivity against interfering species, good stability and high reproducibility of the electro-oxidation response for 400 successive measurements of Ponceau 4 R on a modified electrode after regeneration in 0.1 M NaOH solution are other advantages of the fabricated electrode. The developed sensor was successfully for the analysis of Ponceau 4 R in complex matrices such as fruit juice and jelly samples with acceptable recoveries.