Ultra-trace determination of hexavalent chromium by novel two dimensional biphenol-biphenoquinone nanoribbons/silver nanoparticles

In this study, decorated silver nanoparticles on two dimensional (2D)-biphenol-biphenoquinone nanoribbons (AgNPs-BP-BPQ NRs) were prepared for the first time by a novel, fast and simple method. The mentioned compound was then used as modifier for preparation of modified graphite paste electrode (GPE/AgNPs-BP-BPQ NRs) for indirect voltammetric determination of carcinogen hexavalent chromium (Cr (VI). Peak current of BP/BPQ redox system was decreased in the presence of Cr (VI), hence, this decrease in peak current was used as the electroanalytical signal for quantitative determination of Cr (VI). Moreover, the redox reaction of Cr (VI) and BP was investigated in this study for the first time and the product was characterized. Different techniques such as field emission electron microscopy, Energy-dispersive X-ray spectroscopy, transmission electron microscopy, atomic force microscopy and fourier transform infrared spectroscopy were performed for characterization of the AgNPs-BP-BPQ NRs. Different electrochemical methods, such as cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry, were employed to study the behavior of Cr (VI) on the proposed modified electrode. Under the optimum conditions, the calibration curve was liner in the ranges of 8.0 x 10(-11) to 1.0 x 10(-8), 1.0 x 10(-8) to 1.0 x 10(-6) and 1.0 x 10(-6) to 1.0 x 10(-4) M with a detection limit of 2.0 x 10(-12) M. Finally, this sensor was successfully used for determination of Cr (VI) in tap water, river water and electroplating waste water samples.