Journal Name RSCPublishing ARTICLE This journal isIn the present work, an electrochemical sensor for nitrobenzene has been developed based on green synthesized silver nanoparticles (AgNPs) decorated reduced graphene oxide (RGO) modified glassy carbon electrode (GCE). The AgNPs were synthesized using Justicia glauca leaf extract as a reducing and stabilizing agent. RGO-AgNPs composite modified electrode was prepared by a simple electrochemical reduction of AgNPs dispersed GO solution. FESEM of RGO-AgNPs composite confirms that AgNPs are firmly attached on the RGO sheets and the average size of AgNPs is found to be 40 ± 5 nm. The modified electrode shows good efficiency with lower overpotential for electrocatalytic reduction of NB than that of other modified electrodes (AgNPs and RGO). The DPV response confirms that the reduction peak current of NB is linear over the concentrations from 0.5 to 900 µM. The sensitivity of the sensors is found to be 0.836 µAµM -1 cm -2 with the detection limit of 0.261 µM for NB.In addition, the RGO-AgNPs composite modified electrode shows good selectivity in the presence of potentially interfering similar compounds and good practicality in the waste water samples.

In the present study, we report the fabrication of silver nanoparticles (AgNPs) decorated on activated screen printed carbon electrode (ASPCE). The AgNPs were prepared by using Justicia glauca leaf extract as a reducing and stabilizing agent and the ASPCE was prepared by a simple electrochemical activation of screen printed carbon electrode (SPCE). The ASPCE/AgNPs shows a reversible electrochemical behaviour with enhanced response for DA than that of other modified SPCEs. Under optimum conditions, the electrochemical oxidation current response of DA is linear over the concentration range from 0.05 to 45.35 µM. The limit of detection is found as 0.017 µM with a high sensitivity of 7.85 µA µM−1 cm−2.

The green synthesis of metal nanoparticles is found to be more attractive in various disciplines, including analytical chemistry. The present study demonstrates a selective voltammetric determination of painter's colic (lead poisoning) using green synthesized gold nanoparticles (Au-NPs) modified glassy carbon electrode (GCE). The Au-NPs were synthesized by the reduction of chloroaurate ions with the fresh leaf extract of Justicia glauca. The formation of Au-NPs was confirmed by UV-visible spectroscopy using surface plasmon resonance. The average size of the synthesized Au-NPs is found to be 32.5 AE 0.25. A good cathodic response current was observed at the Au-NPs modified electrode, whereas the unmodified electrode does not show any response in the presence of Pb 2+ . With optimum condition, the Au-NPs modified electrode exhibits a good response towards Pb 2+ with a linear response range from 0.005 to 800 mM L À1 and the lowest detection limit of 0.07 nM L À1 . The fabricated sensor exhibits a high selectivity towards Pb 2+ in the presence of 100 fold concentrations of other metal ions. In addition, the proposed sensor also shows a good practicality towards Pb 2+ in river water samples. Fig. 2 Differential pulse voltammetric response of the bare (a) and Au-NPs (b) modified glassy carbon electrode response to 100 mM L À1 Pb 2+ in N 2 saturated pH 5 solution.This journal is

In the present study, we report the simultaneous electrochemical determination of hydroquinone (HQ), catechol (CC) and resorcinol (RC) at gold nanoparticles (Au‐NPs) decorated reduced graphene oxide (RGO) modified electrode. An enhanced and well defined peak current response with a better peak separation of HQ, CC and RC is observed at RGO/Au‐NPs composite than that of RGO and Au‐NPs modified electrodes. The fabricated modified electrode shows a wide linear response in the concentration range of 3–90 µM, 3–300 µM and 15–150 µM for HQ, CC and RC, respectively. The detection limit of HQ, CC and RC is found as 0.15 µM, 0.12 µM and 0.78 µM, respectively.