Intensifed Pb(II) adsorption using functionalized KCC‑1 synthesized from rice husk ash in batch and column adsorption studies

An attempt to investigate the feasibility of 3-aminopropyltriethoxysilane (3-APTES)-functionalized KCC-1 (NH2/KCC-1) prepared from rice husk ash (RHA) for Pb(II) removal was executed. An effective functionalization of fibrous silica nanospeheres (KCC-1) by NH3 was confirmed by FTIR analysis. The optimized condition of Pb(II) adsorption in the batch system was at an initial Pb(II) concentration (X1) of 307 mg/L, adsorbent dosage (X2) of 2.43 g/L, and time (X3) of 114 min, with the Pb(II) removal (Y) of 90.1% (predicted) and 91.2% (actual). NH2/KCC-1 can be regenerated by nitric acid (0.1 M) with insignificant decline of Pb(II) removal percentage (adsorption=91.2–67.3%, desorption=77.7–51.9%) during 5 cycles adsorption–desorption study. The examination of column adsorption study at a varying flow rate (1–3 mL/min) and bed height (10–20 cm) showed a good performance at a lower flow rate and higher bed height. Both Adam–Bohalt model and Thomas model displayed a good correlation with experimental data. However, Thomas model was more suitable due to the high correlation coefficient, R2=0.91–0.99. This study revealed the intensified Pb(II) adsorption using NH2/KCC-1 synthesized from RHA in batch and column adsorption studies

Green chemistry and coronavirus

The novel coronavirus pandemic has rapidly spread around the world since December 2019. Various techniques have been applied in identification of SARS-CoV-2 or COVID-19 infection including computed tomography imaging, whole genome sequencing, and molecular methods such as reverse transcription polymerase chain reaction (RT-PCR). This review article discusses the diagnostic methods currently being deployed for the SARS-CoV-2 identification including optical biosensors and point-of-care diagnostics that are on the horizon. These innovative technologies may provide a more accurate, sensitive and rapid diagnosis of SARS-CoV-2 to manage the present novel coronavirus outbreak, and could be beneficial in preventing any future epidemics. Furthermore, the use of green synthesized nanomaterials in the optical biosensor devices could leads to sustainable and environmentally-friendly approaches for addressing this crisis. © 202

A screen printed electrode modified with Fe3O4@polypyrrole-Pt core-shell nanoparticles for electrochemical detection of 6-mercaptopurine and 6-thioguanine

In this paper, Fe3O4@ppy-Pt core-shell nanoparticles (NPs) could be produced and utilized for the development of a novel electrochemical sensor to detect 6-mercaptopurine (6-MP). 6-MP determination was examined by cyclic voltammetry (CV), chronoamperometry (CHA), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) at Fe3O4@ppy-Pt core-shell NPs modified screen printed electrode (Fe3O4@ppy-Pt/SPE) in phosphate buffered solution (PBS). The outcomes obtained from DPV demonstrated that the Fe3O4@ppy-Pt/SPE proved a linear concentration range among 0.04 and 330.0 μM having a detection limit of 10.0 nM for 6-MP. Also, modified electrode was satisfactorily utilized to detect 6-MP in the presence of 6-thioguanine (6-TG). This sensor showed two separate oxidative peaks at 530 mV for 6-MP and at 730 mV for 6-TG with a peak potential separation of 200 mV which was large enough for simultaneous detection of the two anticancer drugs. In addition, the proposed sensor presented long-term stability, good repeatability, and excellent reproducibility. Finally, the modified electrode demonstrated satisfactory outcomes while used in real samples, proposing the appropriate potential of Fe3O4@ppy-Pt/SPE in the case of clinical diagnosis, biological samples and pharmaceutical compounds analysis. © 2021 Elsevier B.V

A simple and sensitive approach for the electrochemical determination of amaranth by a Pd/GO nanomaterial-modified screen-printed electrode

It is essential to develop easy-to-use sensors towards a better monitoring of food additives so that human health can be positively influenced. A type of critical food additive that is widely used in making soft drinks and diverse foodstuff is called amaranth. This study aimed at presenting a novel Pd/GO nanomaterial-modified screen-printed electrode (Pd/GO/SPE), which is responsible for providing a sensing interface during the process of specifying the electrochemical features of amaranth. The morphology and structure of the Pd/GO nanomaterial was investigated by Fourier-transform infrared spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy. When the optimized conditions was adjusted, Pd/GO/SPE proved to be a capable sensor for conducting a very sensitive sensing towards the amaranth under a common working situation of 575 mV. In this regard, it was embarked on measuring some of the sensor features, including its sensitivity, linear dynamic range, and detection limit for amaranth with the values of 0.0948 μA μM�1, 0.08 μM-360.0 μM and 30.0 nM were obtained, respectively. © The Royal Society of Chemistry 2020

BN-Fe3O4-Pd nanocomposite modified carbon paste electrode: Efficient voltammetric sensor for sulfamethoxazole

The present research presents synthesis and substantial utilization of a nanocomposite of boron nitride-Fe3O4�Pd (BN�Fe3O4�Pd) for modifying carbon paste electrode (CPE) to determine sulfamethoxazole (SMZ). Various techniques such as transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were applied to characterize the synthesized nanocomposite. In addition, differential pulse voltammetry (DPV) was employed for anodic peak and quantitatively detecting SMZ. Based on the optimized condition, this novel sensor exhibited a linear response of 0.02�420.0 μM. The limitation of detection and quantitation values for SMZ were determined to be 0.008 μM and 0.027 μM, respectively. Moreover, this electrode could substantially be applied for the analysis of SMZ in the real samples (e.g., urine, tap water, river water). © 2021 Elsevier Ltd and Techna Group S.r.l

Recent Advances in Applications of Voltammetric Sensors Modified with Ferrocene and Its Derivatives

This study is on current developments concerning ferrocene (FC) and its derivatives on the basis of electrochemical biosensors and sensors. The distinct physiochemical characteristics of FC have enabled the development of new sensor devices, specifically electrochemical sensors. Several articles have focused on the implementation of FC as an electrode constituent while discussing its electrochemical behavior. Furthermore, typical FC-design-based biosensors and sensors are considered as well as practical examples. The favorable design of FC-based biosensors and general sensors needs adequate control of their chemical and physical characteristics in addition to their surface immobilization and functionalization. Copyright © 2020 American Chemical Society

Carbon and graphene quantum dots: A review on syntheses, characterization, biological and sensing applications for neurotransmitter determination

Neuro-transmitters have been considered to be essential biochemical molecules, which monitor physiological and behavioral function in the peripheral and central nervous systems. Thus, it is of high pharmaceutical and biological significance to analyze neuro-transmitters in the biological samples. So far, researchers have devised a lot of techniques for assaying these samples. It has been found that electro-chemical sensors possess features of robustness, selectivity, and sensitivity as well as real-time measurement. Graphene quantum dots (GQDs) and carbon QDs (CQDs) are considered some of the most promising carbon-based nanomaterials at the forefront of this research area. This is due to their characteristics including lower toxicity, higher solubility in various solvents, great electronic features, strong chemical inertness, high specific surface areas, plenty of edge sites for functionalization, and versatility, in addition to their ability to be modified via absorbent surface chemicals and the addition of modifiers or nano-materials. Hence in the present review, the synthesis methods of GQDs and CQDs has been summarized and their characterization methods also been analyzed. The applications of carbon-based QDs (GQDs and CQDs) in biological and sensing areas, such as biological imaging, drug/gene delivery, antibacterial and antioxidant activity, photoluminescence sensors, electrochemiluminescence sensors and electrochemical sensors, have also been discussed. This study then covers sensing features of key neurotransmitters, including dopamine, tyrosine, epinephrine, norepinephrine, serotonin and acetylcholine. Hence, issues and challenges of the GQDs and CQDs were analyzed for their further development. This journal is © 2020 The Royal Society of Chemistry

Recent developments in voltammetric and amperometric sensors for cysteine detection

This review article aims to provide an overview of the recent advances in the voltammetric and amperometric sensing of cysteine (Cys). The introduction summarizes the important role of Cys as an essential amino acid, techniques for its sensing, and the utilization of electrochemical methods and chemically modified electrodes for its determination. The main section covers voltammetric and amperometric sensing of Cys based on glassy carbon electrodes, screen printed electrodes, and carbon paste electrodes, modified with various electrocatalytic materials. The conclusion section discusses the current challenges of Cys determination and the future perspectives. © The Royal Society of Chemistry 2021