Simultaneous determination of cholesterol, ascorbic acid and uric acid as three essential biological compounds at a carbon paste electrode modified with copper oxide decorated reduced graphene oxide nanocomposite and ionic liquid

t-Butyl calixarene/Fe2O3@MWCNTs composite-based potentiometric sensor for determination of ivabradine hydrochloride in pharmaceutical formulations

Ivabradine hydrochloride (IVB) has shown high medical importance as it is a medication for lowering the heart rate for the symptomatic chronic heart failure and symptomatic management of stable angina pectoralis. The high dose of IVB may cause severe and prolonged bradycardia, uncontrolled blood pressure, headache, and blurred vision. In this study, a highly sensitive carbon-paste electrode (CPEs) was constructed for the potentiometric determination of IVB in pharmaceutical formulations. t-Butyl calixarene (t-BCX) was used as an ionophore due to its ability to mask IVB in the cavity via multiple H-bonding at the lower rim, as estimated quantitatively by the sandwich membrane method (Log β_ILn = 8.62). Besides, the use of multi-walled carbon nanotubes decorated with Fe₂O₃ nanoparticles (Fe₂O₃@MWCNTs) as an additive for the paste electrode significantly improved the detection limit of the sensor up to 36 nM, with Nernstian response of 58.9 mV decade^-1 in the IVB linear dynamic range of 10^-3-10^-7 M in aqueous solutions. The constructed sensors showed high selectivity against interfering species that may exist in physiological fluids or pharmaceutical formulations (e.g. Na⁺, K⁺, NH₄⁺, Ca²⁺, Mg²⁺, Ba²⁺, Fe³⁺, Co²⁺, Cr³⁺, Sr²⁺, glucose, lactose, maltose, glycine, dopamine, and ascorbic acid). The sensors were successfully employed for IVB determination in the pharmaceutical formulations (Savapran®).

Determination of Ursolic Acid in Extracts From Ligustri lucidum Fruit Using an Electrochemical Method

In this work, we reported a facile wet chemical method for depositing Pt nanoparticles on the surface of boron nitride nanosheets (BNNS-Pt NPs). The deposited nanocomposite was applied for glassy carbon electrode surface modification. The modified electrode was then used for detecting ursolic acid (UA). The results indicate that the BNNS-Pt NPs exhibited excellent electrocatalytic activity toward UA oxidation compared with that of the bare glassy carbon electrode (GCE) and Pt NPs/GCE. The UA oxidation currents is linearly related its concentration from 1 to 1,200 pM. The limit of detection can be calculated to be 0.5 pM. In addition, the UA sensor was also successfully used for the determination of UA in Ligustri lucidum fruit samples.

Monodisperse thiourea functionalized graphene oxide-based PtRu nanocatalysts for alcohol oxidation

Addressed herein, thiourea functionalized graphene oxide-based PtRu nanocatalysts (PtRu@T/GO) has been synthesized and characterized by several techniques and performed for methanol oxidation reactions as novel catalysts. In this study, graphene oxide (GO) was functionalized with thiourea (T/GO) in order to obtain monothiol functionalized graphene and increase the stability and activity of the nanocatalysts. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), TEM (transmission electron microscopy) and high-resolution transmission electron microscopy (HR-TEM) were used for characterization of the prepared nanocatalysts. The results obtained from these techniques showed that the prepared nanocatalysts were in a highly crystalline form, well dispersed on T/GO, very small in size and colloidally stable. The average size of the synthesized nanocatalysts determined by TEM analysis was found to be 3.86 ± 0.59 nm. With HR-TEM analysis, the atomic lattice fringes of the nanocatalysts were calculated to be 0.23 nm. After the full characterization of the prepared nanocatalysts, they were tried for the methanol oxidation reaction (MOR) and it was observed that 97.3% of the initial performance was maintained even after 1000 cycles while exhibiting great catalytic activity and stability with the help of T/GO. Thus, the arranged nanocatalysts displayed great heterogeneous catalyst characteristics for the methanol oxidation response.

Fabrication of magnetic iron oxide-supported copper oxide nanoparticles (Fe3O4/CuO): modified screen-printed electrode for electrochemical studies and detection of desipramine

The present investigation examines a sensitive electrochemical technique to detect desipramine through Fe₃O₄/CuO nanoparticles (NPs). Fe₃O₄/CuO NPs were synthesized via a coprecipitation procedure, and the products were characterized via energy disperse spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and vibrating sample magnetometer. The voltage–current curve and differential pulse voltammetry examinations of Fe₃O₄/CuO-modified screen-printed electrode (Fe₃O₄/CuO/SPE) were followed by the determination of electro-catalytic activities toward desipramine oxidation in a phosphate buffer solution (pH = 7.0). In addition, the value of diffusion coefficient (D = 3.0 × 10⁻⁶ cm² s⁻¹) for desipramine was calculated. Then, based on the optimum conditions, it was observed that the currents of the oxidation peak were linearly proportionate to the concentration of desipramine in the broad range between 0.08 and 400.0 μM and LOD of 0.03 μM (S/N = 3). Finally, our new sensor was successfully utilized to detect desipramine in the real samples, with reasonable recovery in the range of 97.2% to 102.7%.

The present investigation examines a sensitive electrochemical technique to detect desipramine through Fe₃O₄/CuO nanoparticles.

Green polymeric nanomaterials for the photocatalytic degradation of dyes: a review

Pure and drinkable water will be rarer and more expensive as the result of pollution induced by industrialisation, urbanisation and population growth. Among the numerous sources of water pollution, the textile industry has become a major issue because effluents containing dyes are often released in natural water bodies. For instance, about two years are needed to biodegrade dye-derived, carcinogenic aromatic amines, in sediments. Classical remediation methods based upon physicochemical reactions are costly and still generate sludges that contain amine residues. Nonetheless, recent research shows that nanomaterials containing biopolymers are promising to degrade organic pollutants by photocatalysis. Here, we review the synthesis and applications of biopolymeric nanomaterials for photocatalytic degradation of azo dyes. We focus on conducting biopolymers incorporating metal, metal oxide, metal/metal oxide and metal sulphide for improved biodegradation. Biopolymers can be obtained from microorganisms, plants and animals. Unlike fossil-fuel-derived polymers, biopolymers are carbon neutral and thus sustainable in the context of global warming. Biopolymers are often biodegradable and biocompatible.

Simplistic one-pot synthesis of an inorganic–organic cubic caged material: a new interface for detecting toxic bisphenol-A electrochemically

Polyhedral oligomeric silsesquioxane (POSS) based hybrid nanomaterials have been terminally functionalised with three different functional groups and are newly explored for the electrochemical sensing of bisphenol A.

Electrochemical Sensors, a Bright Future in the Fabrication of Portable Kits in Analytical Systems

Analysis of food, pharmaceutical, and environmental compounds is an inevitable issue to evaluate quality of the compounds used in human life. Quality of drinking water, food products, and pharmaceutical compounds is directly associated with human health. Presence of forbidden additives in food products, toxic compounds in water samples and drugs with low quality lead to important problems for human health. Therefore, attention to analytical strategy for investigation of quality of food, pharmaceutical, and environmental compounds and monitoring presence of forbidden compounds in materials used by humans has increased in recent years. Analytical methods help to identify and quantify both permissible and unauthorized compounds present in the materials used in human daily life. Among analytical methods, electrochemical methods have been shown to have more advantages compared to other analytical methods due to their portability and low cost. Most of big companies have applied this type of analytical methods because of their fast and selective analysis. Due to simple operation and high diversity of electroanalytical sensors, these types of sensors are expected to be the future generation of analytical systems. Therefore, many scientists and researchers have focused on designing and fabrication of electroanalytical sensors with good selectivity and high sensitivity for different types of compounds such as drugs, food, and environmental pollutants. In this paper, we described the mechanism and different examples of DNA, enzymatic and electro-catalytic methods for electroanalytical determination of drug, food and environmental compounds.