Novel Aminosilane (APTES)-Grafted Polyaniline@Graphene Oxide (PANI-GO) Nanocomposite for Electrochemical Sensor

Lead is a potentially toxic element (PTE) that has several adverse medical effects in humans. Its presence in the environment became prominent due to anthropogenic activities. The current study explores the use of newly developed composite materials (organic–inorganic hybrid) based on PANI-GO-APTES for electrochemical detection of Pb2+ in aqueous solution. The composite material (PANI-GO-APTES) was synthesized by chemical method and was characterized with SEM, XPS, XEDS, XRD, TGA, FTIR, EIS and CV. The result of characterization indicates the successful synthesis of the intended material. The PANI-GO-APTES was successfully applied for electrochemical detection of Pb2+ using cyclic voltammetry and linear sweep voltammetry method. The limit of detection of Pb2+ was 0.0053 µM in the linear range of 0.01 µM to 0.4 µM. The current response produced during the electrochemical reduction of Pb2+ catalyzed by PANI-GO-APTES was also very repeatable, reproducible and rapid. The application of PANI-GO-APTES-modified GCE in real sample analysis was also established. Therefore, PANI-GO-APTES is presented as a potential Pb2+ sensor for environmental and human health safety

Sensitive Electrochemical Detection of 4-Nitrophenol with PEDOT:PSS Modified Pt NPs-Embedded PPy-CB@ZnO Nanocomposites

In this study, a selective 4-nitrophenol (4-NP) sensor was developed onto a glassy carbon electrode (GCE) as an electron-sensing substrate, which decorated with sol–gel, prepared Pt nanoparticles- (NPs) embedded polypyrole-carbon black (PPy-CB)/ZnO nanocomposites (NCs) using differential pulse voltammetry. Characterizations of the NCs were performed using Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Ultraviolet–visible Spectroscopy (UV–vis), Fourier Transform Infrared Spectroscopy (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction Analysis (XRD). The GCE modified by conducting coating binders [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate; PEDOT:PSS] based on Pt NPs/PPy-CB/ZnO NCs functioned as the working electrode and showed selectivity toward 4-NP in a phosphate buffer medium at pH 7.0. Our analysis of 4-NP showed the linearity from 1.5 to 40.5 µM, which was identified as the linear detection range (LDR). A current versus concentration plot was formed and showed a regression co-efficient R2 of 0.9917, which can be expressed by ip(µA) = 0.2493C(µM) + 15.694. The 4-NP sensor sensitivity was calculated using the slope of the LDR, considering the surface area of the GCE (0.0316 cm2). The sensitivity was calculated as 7.8892 µA µM−1 cm−2. The LOD (limit of detection) of the 4-NP was calculated as 1.25 ± 0.06 µM, which was calculated from 3xSD/σ (SD: Standard deviation of blank response; σ: Slope of the calibration curve). Limit of quantification (LOQ) is also calculated as 3.79 µM from LOQ = 10xLOD/3.3. Sensor parameters such as reproducibility, response time, and analyzing stability were outstanding. Therefore, this novel approach can be broadly used to safely fabricate selective 4-NP sensors based on nanoparticle-decorated nanocomposite materials in environmental measurement

Efficient Detection of 2,6-Dinitrophenol with Silver Nanoparticle-Decorated Chitosan/SrSnO₃ Nanocomposites by Differential Pulse Voltammetry

Herein, an ultra-sonication technique followed by a photoreduction technique was implemented to prepare silver nanoparticle-decorated Chitosan/SrSnO3 nanocomposites (Ag-decorated Chitosan/SrSnO3 NCs), and they were successively used as electron-sensing substrates coated on a glassy carbon electrode (GCE) for the development of a 2,6-dinitrophenol (2,6-DNP) efficient electrochemical sensor. The synthesized NCs were characterized in terms of morphology, surface composition, and optical properties using FESEM, TEM, HRTEM, BET, XRD, XPS, FTIR, and UV-vis analysis. Ag-decorated Chitosan/SrSnO3 NC/GCE fabricated with the conducting binder (PEDOT:PSS) was found to analyze 2,6-DNP in a wide detection range (LDR) of 1.5~13.5 µM by applying the differential pulse voltammetry (DPV) approach. The 2,6-DNP sensor parameters, such as sensitivity (54.032 µA µM−1 cm−2), limit of detection (LOD; 0.18 ± 0.01 µM), limit of quantification (LOQ; 0.545 µM) reproducibility, and response time, were found excellent and good results. Additionally, various environmental samples were analyzed and obtained reliable analytical results. Thus, it is the simplest way to develop a sensor probe with newly developed nanocomposite materials for analyzing the carcinogenic contaminants from the environmental effluents by electrochemical approach for the safety of environmental and healthcare fields in a broad scale

Synthesis and Characterization of Eco-Friendly Bio-Composite from Fenugreek as a Natural Resource

The present study show the usability of starch (tamarind) based-bio-composite film reinforced by fenugreek by various percentages to replace the traditional petrochemical plastics. The prepared bio-composite films were systematically characterized using the universal testing machine (UTM), soil degradation, scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and antibacterial tests. The experiments showed that a lower percentage of fenugreek improves biodegradation and mechanical strength. More than 60% of biodegradation occurred in only 30 days. Almost 3 N/mm2 tensile strength and 6.5% tensile strain were obtained. The presence of micropores confirmed by SEM images may accelerate the biodegradation process. Antibacterial activity was observed with two samples of synthesized bio-composite, due to photoactive compounds confirmed by FTIR spectra. The glass transition temperature was shown to be higher than the room temperature, with the help of thermal analysis. The prepared bio-composite containing 5% and 10% fenugreek showed antibacterial activities

Optimization of Ultrasonic-Assisted Enzymatic Extraction of Freeze-Dried Sea Buckthorn (<i>Hippophae rhamnoides</i> L.) Berry Oil Using Response Surface Methodology

The ultrasound-assisted extraction (UAE) of oil has received immense importance nowadays because of the enormous benefits the process offers. However, the literature evaluating this process is scarce for sea buckthorn oil. Furthermore, to date, to the best of our knowledge, a study evaluating the combined use of enzymes and UAE for this oil is lacking. In this study, oil from freeze-dried sea buckthorn berries was extracted using ultrasound-assisted enzymatic extraction (UAEE) and the effect of variables (time, enzyme concentration, and solvent to sample ratio) was evaluated on oil yield and its physiochemical properties (acid value, peroxide value, iodine value, density, and color). The optimum conditions were determined using the response surface methodology. The optimum conditions established were 5.08 mL/g, 14.65 min, and 3.13 U/g for a solvent to sample ratio, ultra-sonication time, and enzyme units, respectively. The oil yield was 18.32%. Physicochemical parameters were found better in UAEE oil than in the Soxhlet-extracted oil. Gas chromatography detected relatively higher levels of fatty acids, including palmitic, palmitoleic, and oleic acids in UAEE oil. The optimum conditions were also verified for adequacy by validation and results were matched with predicted values with 0.8 to 1.5 error %, which states that the model can be utilized to predict oil yield percentage