Electrochemical sensing of hydrogen peroxide based on nano γ-Fe2O3 modified glassy carbon electrode

162-166Maghemite (γ-Fe2O3) nanoparticles were prepared using chemical synthesis method and used for sensing the hydrogen peroxide. The morphology of the γ-Fe2O3 nanoparticles was characterized by scanning electron microscopy. The γ-Fe2O3 nanoparticles were used to modify glassy carbon electrode (GCE) to form nano γ-Fe2O3 modified GC electrode for electrochemical sensing of hydrogen peroxide (H2O2). A potential controlled cyclic voltammetric (CV) technique was performed to sense hydrogen peroxide using nano γ-Fe2O3 modified GC electrode. The nano γ-Fe2O3 modified GC electrode showed excellent electrocatalytic ability towards H2O2 in 0.1M KCl supporting electrolyte. A significant enhancement in anodic peak current was observed for the nano γ-Fe2O3 modified GC electrode than those of bare electrode. The electrochemical characteristics of hydrogen peroxide on nano γ-Fe2O3 modified GC electrode  had been explored in this research communication

Electrochemical sensing of hydrogen peroxide based on nano γ-Fe2O3 modified glassy carbon electrode

Maghemite (γ-Fe2O3) nanoparticles were prepared using chemical synthesis method and used for sensing the hydrogen peroxide. The morphology of the γ-Fe2O3 nanoparticles was characterized by scanning electron microscopy. The γ-Fe2O3 nanoparticles were used to modify glassy carbon electrode (GCE) to form nano γ-Fe2O3 modified GC electrode for electrochemical sensing of hydrogen peroxide (H2O2). A potential controlled cyclic voltammetric (CV) technique was performed to sense hydrogen peroxide using nano γ-Fe2O3 modified GC electrode. The nano γ-Fe2O3 modified GC electrode showed excellent electrocatalytic ability towards H2O2 in 0.1M KCl supporting electrolyte. A significant enhancement in anodic peak current was observed for the nano γ-Fe2O3 modified GC electrode than those of bare electrode. The electrochemical characteristics of hydrogen peroxide on nano γ-Fe2O3 modified GC electrode  had been explored in this research communication

Emerging MXene–Polymer Hybrid Nanocomposites for High-Performance Ammonia Sensing and Monitoring

Ammonia (NH3) is a vital compound in diversified fields, including agriculture, automotive, chemical, food processing, hydrogen production and storage, and biomedical applications. Its extensive industrial use and emission have emerged hazardous to the ecosystem and have raised global public health concerns for monitoring NH3 emissions and implementing proper safety strategies. These facts created emergent demand for translational and sustainable approaches to design efficient, affordable, and high-performance compact NH3 sensors. Commercially available NH3 sensors possess three major bottlenecks: poor selectivity, low concentration detection, and room-temperature operation. State-of-the-art NH3 sensors are scaling up using advanced nano-systems possessing rapid, selective, efficient, and enhanced detection to overcome these challenges. MXene–polymer nanocomposites (MXP-NCs) are emerging as advanced nanomaterials of choice for NH3 sensing owing to their affordability, excellent conductivity, mechanical flexibility, scalable production, rich surface functionalities, and tunable morphology. The MXP-NCs have demonstrated high performance to develop next-generation intelligent NH3 sensors in agricultural, industrial, and biomedical applications. However, their excellent NH3-sensing features are not articulated in the form of a review. This comprehensive review summarizes state-of-the-art MXP-NCs fabrication techniques, optimization of desired properties, enhanced sensing characteristics, and applications to detect airborne NH3. Furthermore, an overview of challenges, possible solutions, and prospects associated with MXP-NCs is discussed

Highly Sensitive and Selective Hydrogen Gas Sensor with Humidity Tolerance Using Pd-Capped SnO₂ Thin Films of Various Thicknesses

Detecting and identifying hydrogen gas leakage before a potential disaster is a critical safety concern. To address this issue, a low-cost and simple-design sensor is required with high response and fast sensing time, capable of detecting hydrogen gas even at low concentrations of 5–500 ppm. This study investigates the use of magnetron-sputtered SnO2 thin films with palladium as a catalytic layer to achieve better sensing output. The developed Pd-caped SnO2 thin film sensors showed increased sensitivity with increasing thickness, up to 246.1 nm at an operating temperature of 250 °C. The sensor with a thickness of 246.1 nm exhibited excellent selectivity for H2 gas, even in humid conditions, and was able to distinguish it from other gases such as CO, NH3, and NO2. The sensor demonstrated high response (99%) with a response/recovery time of 58 s/35 s for (5–500 ppm) hydrogen gas. The sensor showed linear response to H2 gas concentration variation (5–500 ppm) at 250 °C. The sensor was found to be mechanically stable even after 60 days in a high-humidity environment. The LOD of sensor was 151.6 ppb, making it a suitable candidate for applied sensing applications. The Pd-caped SnO2 thin film sensor with thickness of ~245 nm could potentially improve the safety of hydrogen gas handling

Hydrogen induced resistance and optical transmittance of pulsed laser deposited Pd/Mg thin films

96-100The hydrogen detection is an important issue for the societal acceptance of H2 as energy carrier. In present research work, we have investigated hydrogen sensing and optical properties of Pd/Mg thin films on glass substrate deposited by pulsed laser (PL). As-deposited thin films have been exposed (hydrogenation) to H2 gas (2 bar) at room temperature in a hydrogenation unit. Hydrogenated and dehydrogenated (at different temperatures) samples have been characterized using X-ray diffractometer (XRD), field-emission scanning electron microscopy (FE-SEM), UV-Vis-NIR spectrophotometer, atomic force microscopy (AFM). XRD results confirm the formation of hydride (MgH2) tetragonal phase upon hydrogenation of Pd/Mg films. Hydrogen induced resistance response of Pd/Mg films has been measured in-situ during hydrogenation/dehydrogenation process by using two- probe electrical method. The response time (sensitivity) of Pd/Mg films for hydrogen gas is ~ 60 s at room temperature. The study of optical transmittance of hydrogenated Pd/Mg films indicates their switchable mirror behavior

Annealing-assisted SnO2 Thin Film for Selective Hydrogen Gas Sensor

823-829Today, monitoring and classification of hydrogen gas by metal oxide-based sensors are widely studying to improve their selectivity and stability. In present work, hydrogen sensing properties of magnetron sputtered deposited pure SnO2 thin films have been studied. The pure SnO2 thin film was deposited on glass substrate and as-deposited film was annealed at 450 °C for 6 hrs. The annealed SnO2 thin film has crystalline tetragonal structure, granular surface morphology and non-stoichiometry elemental composition of tin and oxygen vacancies. A higher gas sensing response is obtained for annealed SnO2 thin film as compare to as-deposited SnO2 thin film.A limit of detection (LOD) ~175 ppb is estimated for annealed SnO2 thin filmbased sensor. This sensor exhibits fast response and recovery time of 42 s/52 s for 50 and 500 ppm hydrogen gas, respectively. The sensor is found highly selective towards H2 gas in compare to different gases such as methane, carbon monoxide and nitrogen dioxide

Role of environmental factors & oxidative stress with respect to in vitro fertilization outcome

Background & objectives: Oxidative stress, lifestyle factors as also exposure to certain environmental factors are known to affect the fertility status in human beings. The aim of this study was to evaluate the role of OS and lifestyle and environmental factors affecting IVF outcome. Methods: A total of 253 couples were included, and biological samples such as blood, follicular fluid (FF), cumulus cells and semen were collected. Relevant biochemical parameters and metals namely lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) were determined in the biological samples. β-human chorionic gonadotropin levels ≥100 IU/l were considered to predict viable pregnancy on the 15th day of embryo transfer (ET). Results: The mean body mass index (BMI) was significantly lower in females with positive IVF outcome compared to those with negative outcome. Couples residing in the residential area showed more percentage of positive IVF outcomes as compared to couples residing in industrial/agricultural area. FF Zn level was significantly higher (P<0.001) among the females' participants who have undergone ET as compared to those who have not undergone ET. FF MDA and serum Cu levels were significantly higher (P<0.05) in the female participants with negative IVF outcome as compared to positive IVF outcome. Logistic regression revealed that maternal BMI (P=0.034) and FF MDA level (P=0.047) were significantly associated with the IVF outcome. Interpretation & conclusions: The success rate of IVF was about 31.8 per cent, and BMI was significantly lower in females with positive outcome. The higher levels of MDA in FF and SP might have a negative impact on IVF outcome, higher Zn level in SP, FF and serum might have a positive role in embryo transfer as well as IVF outcome. The role of stress management and nutrition supplementation during the IVF treatment may be explored

Expression of accessory colonization factor subunit A (ACFA) of Vibrio cholerae and ACFA fused to cholera toxin B subunit in transgenic tomato (Solanum lycopersicum)

In earlier study from our group, cholera toxin B subunit had been expressed in tomato for developing a plant-based vaccine against cholera. In the present investigation, gene for accessory colonization factor (acf) subunit A, earlier reported to be essential for efficient colonization in the intestine, has been expressed in Escherichia coli as well as tomato plants. Gene encoding for a chimeric protein having a fusion of cholera toxin B subunit and accessory colonization factor A was also expressed in tomato to generate more potent combinatorial antigen. CaMV35S promoter with a duplicated enhancer sequence was used for expression of these genes in tomato. Integration of transgenes into tomato genome was confirmed by PCR and Southern hybridization. Expression of the genes was confirmed at transcript and protein levels. Accessory colonization factor A and cholera toxin B subunit fused to this protein accumulated up to 0.25% and 0.08% of total soluble protein, respectively, in the fruits of transgenic plants. Whereas protein purified from E. coli, in combination with cholera toxin B subunit can be used for development of conventional subunit vaccine, tomato fruits expressing these proteins can be used together with tomato plants expressing cholera toxin B subunit for development of oral vaccine against cholera