In this report, we discussed rapid, facile one-pot green synthesis of gold and silver nanoparticles (AuNPs and AgNPs) by using tuber extract of Amorphophallus paeoniifolius, and evaluated their antibacterial activity. AuNPs and AgNPs were synthesized by mixing their respective precursors (AgNO₃ and HAuCl₄) with tuber extract of Amorphophallus paeoniifolius as the bio-reducing agent. Characterization of AuNPs and AgNPs were confirmed by applying UV-vis spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS). From UV-vis characterization, surface plasmon resonance spectra were found at 530 nm for AuNPs and 446 nm for AgNPs. XRD data confirmed that both synthesized nanoparticles were face-centered cubic in crystalline nature, and the average crystallite sizes for the assign peaks were 13.3 nm for AuNPs and 22.48 nm for AgNPs. FTIR data evaluated the characteristic peaks of different phytochemical components of tuber extract, which acted as the reducing agent, and possibly as stabilizing agents. The antibacterial activity of synthesized AuNPs and AgNPs were examined in Muller Hinton agar, against two Gram-positive and four Gram-negative bacteria through the disc diffusion method. AuNPs did not show any inhibitory effect, while AgNPs showed good inhibitory effect against both Gram-positive and Gram-negative bacteria.

An electrochemical sensor based on a cobalt oxide nanorod (Co₃O₄NR) modified glassy carbon electrode (GCE) (Co₃O₄NR-GCE) was prepared for simultaneous and selective determination of hydroquinone (HQ) and catechol (CT). Surface morphology and crystallinity of Co₃O₄NR were investigated employing field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The structure (16 nm) of the Co₃O₄ nanorod was observed in the FESEM image. A sharp peak pattern in the XRD survey revealed the following crystal planes in Co₃O₄NR material: (111), (220), (311), (222), (400), (422), (511), and (440). Electrochemical characterization of modified Co₃O₄NR-GCE was carried out performing cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Selective and simultaneous detection of HQ and CT was carried out by performing CV and differential pulse voltammetry (DPV) analysis. In both studies, modified Co₃O₄NR-GCE showed well defined oxidation and reduction peaks for HQ and CT with enhanced peak current, and the oxidation peaks for HQ and CT were observed at 0.152 V and 0.254 V, respectively, in the CV analysis. Scan rate and pH variation analysis were performed to evaluate different kinetic parameters, including charge transfer coefficient (α = 0.56 for HQ and 0.66 for CT), heterogeneous charge transfer rate constant (k_s = 56 for HQ and 72 for CT), and the number of electrons involved in HQ and CT oxidation. Quantitative analysis of HQ and CT was studied by observing the current response of DPV analysis with respect to concentration variation. Here, the detection limit was calculated as 0.2 µM for HQ with a linear concentration range of 5–200 µM, and 0.4 µM for CT with a linear concentration range of 5–150 µM. The practical applicability of the proposed sensor was investigated using sample solutions prepared in tap water. The reported sensor showed impressive selectivity towards HQ and CT in the presence of common interferents.

In this article, an electrochemical sensor was prepared for the simultaneous detection of hydroquinone (HQ) and catechol (CT) by incorporating porous tal palm carbon nanosheets (PTPCNS) as the modifier substance on the surface of glassy carbon electrode (GCE). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to characterize the electrochemical properties of the designed (PTCNS/GCE) sensor. PTPCNS/GCE demonstrated excellent electro‐catalytic property toward resolving the individual voltametric signal of HQ and CT from their mixture. Differential pulse voltammetry (DPV) was applied to quantify the lower limit of HQ and CT. The calculated limit of detection (LOD) was 0.15 µM for HQ with the linear range of 1–300 µM and 0.49 µM for CT with the corresponding linear range 5–225 µM obtained for the proposed sensor. The limit of quantification (LOQ) was found 0.51 µM and 1.63 µM for HQ and CT, respectively. Modified PTPCNS/GCE exhibited excellent selectivity towards HQ and CT even in presence of 10 folds potential interference. The practical applicability of the proposed sensor was analyzed in tap water sample with an excellent recovery of 98–104% for HQ and 99–102% for CT.