Sensors International最新文献

Epilepsy is a chronic neurological disease and its treatment requires the use of anti–epileptic drugs. The determination of anti–epileptic drugs in pharmaceutical and biological samples is carried out using various analytical methods. Potentiometric methods, which have a very important place in electroanalytical chemistry, are used extensively in the determination of various drugs in biological and pharmaceutical samples. In this study, we reviewed potentiometry–based sensors developed for the determination of anti–epileptic drug molecules in biological and pharmaceutical samples.

This work introduced a novel electronic device for simultaneous determination of ferritin and transferrin in real matrices. Here, a pencil graphite electrode was chosen as a platform and its surface was modified with multiwalled carbon nanotubes-ionic liquid and electrochemically reduced fullerene-C₆₀. Finally, the surface of the biosensor was modified by dual template molecularly imprinted polymers which were produced by electropolymerization of 2-amino-5-mercapto-1, 3, 4-thiadiazole, and ferritin and transferrin as template molecules. To generate a square wave voltammetric signal from the biosensor to simultaneous determination of ferritin and transferrin, it was incubated into a solution having ferritin and transferrin and then, it was immersed into an electrochemical probe solution. By incubation of the biosensor with ferritin and transferrin, the pathways within its molecularly imprinted polymer layer were occupied by ferritin and transferrin therefore, it was reasonable to observe decreasing of the height of its square wave voltammetric response. Because of the nature of the square wave voltammetric data (potential shifts), incubation of the biosensor with ferritin and transferrin produced two severely overlapped peaks while incubation of the biosensor with both of them generated a single peak. Therefore, for simultaneous determination of ferritin and transferrin, the biosensor was assisted by three-way calibration with the help of second-order square wave voltammetric data which helped me to develop a very efficient electronic device for simultaneous determination of ferritin (sensitivity: 6.5 ​μA ​nM⁻¹, limit of detection: 0.01 ​nM) and transferrin (sensitivity: 6.1 ​μA ​nM⁻¹, limit of detection: 0.012 ​nM) in serum samples whose performance was comparable with a reference method.

Mechatronics has become an inevitable trend in the development of the industry, manufacturing industry in the rapid development of today has also driven the innovation of technology. In the development process of mechatronics, flexible sensors stand out, flexible sensors have the characteristics of flexibility, and a wider range of applications, which is the frontier direction of contemporary electromechanical development. Mechanical and electronic engineering is for the traditional engineering disciplines, the teaching process of students to accept concepts and other content ability is poor, lack of interest, the need for new solutions to solve problems. And by using flexible sensors in exemplary teaching, electromechanical knowledge can be taught more effectively, which can enhance students' vision, learning ability, indepe, dance, and innovation. In this paper, we outline the principles of flexible sensors, and sensors in electromechanical engineering, the advantages and disadvantages of each type of flsensorsensors, and their broad prospects for electromechanical teaching applications.

We report a liquid-level sensor composed of a laser, prism, and photodiode array. The sensor does not require components, such as a sensor head, inside the container that stores liquid. The sensor detects the liquid level based on the difference between the intensities of laser light reflected at the liquid/glass and air/glass interfaces. As the detected liquid level shows a shift from the correct liquid level owing to surface tension and the broadening of the laser light, we correct the shift through calculations. The sensor can be attached to a flange-type glass viewport, providing compatibility with broad-ranging containers for industrial use. The sensor can accurately detect the liquid level with a maximum error of 0.3875 ​mm. We demonstrate the implementation and operation of the liquid-level sensor using a wireless system comprising a sensor head and wireless voltmeter. The reported sensor allows accurate measurement of the liquid level in a tank inside which foreign objects such as sensor heads cannot be installed.

Covid-19 is a dreadful pandemic of the 21st century that has created fear among people, affected the whole world, and taken thousands of lives. It infects the respiratory system and causes flu-type symptoms. According to the WHO reports, 2,082,745 deaths and 96,267,473 confirmed cases were perceived all around the globe till January 22, 2021. The significant roots of transmission are inhalation and direct contact with the infected surface. Its incubation period is 2–14 days and remains asymptomatic in most people. However, no treatment and vaccine are available for the people, so preventive measures like social distancing, wearing personal protective equipment (PPE), and frequent hand-washing are the practical and only options for cure. It has affected every sector of the world, whether it is trade or health all around the world. There is high demand for diagnostic tools as high-scale and expeditious testing is crucial for controlling disease spread; thus, detection methods play an essential role. Like flu, Covid-19 is also detected through RT-PCR, as the World Health Organization (WHO) suggested, but it is time taking and expensive method that many countries cannot afford. A vaccine is a crucial aspect of eradicating disease, and for SARS-CoV-2), plasma therapy and antibiotics therapy are used in the early spreading phase. The later stage involves forming a vaccine based on spike protein, N-protein, and whole-viral antigen that effectively immunizes the population worldwide until herd immunity can be achieved.

In this review, we will discuss all possible and developed techniques for identifying SARS-CoV-2 and make a comparison of their specificity, selectivity, and cost; thus, we choose an appropriate method for fast, reliable, and pocket-friendly detection.

In this study, nanocrystalline cupric oxide was produced using a basic, low-cost sonochemical method (CuO). Through powder X-ray diffraction, the phase and nanocrystalline nature of CuO nanoparticles (NPs) were determined. The Kubelka-Monk function revealed that the band gap of CuO in diffuse reflectance spectra (DRS) is 1.75 ​eV. Ingenious photocatalysts for the removal of the dyes Direct green (DG) and Fast orange red (F-OR) have been demonstrated to work with CuO NPs. To examine the photocatalytic characteristics of NPs under UV light and sunlight irradiation, Direct Green (DG) and Fast Orange Red (F-OR) dyes were utilised as traditional dyes. Direct green dye was found to be excited at 624.1 and 623.8 ​nm in UV and sunlight, while Fast orange red dye is excited at 496.8 and 495.1 ​nm. Lead in 0.1 ​N HCl solution was detected using the cyclic voltammetry (CV) method with a modified carbon paste electrode (MCPE). According to electrochemical performance, CuO is an advantageous sensing electrode material for an element like lead.

Interestingly, this work presents two newly designed copper(II)-selective carbon paste electrodes with distinctively low detection limits which is attained utilizing the Schiff base ligands 2-(2-hydroxyphenylimino)carboxythiophene (L1) and 1,2-di(2-carboxythiopheneimino] benzene (L2). The sensors exhibit a Nernstian slope of 29.10 and 29.28 mVdecade⁻¹ for Cu(II) ion over a wide concentration range from 1.18 ​× ​10⁻⁷ – 1.00 ​× ​10⁻² ​M and 7.91 ​× ​10⁻⁸ – 1.00 ​× ​10⁻² ​M with the detection limits of 1.00 ​× ​10⁻⁷ ​M and 5.28 ​× ​10⁻⁸ ​M for L1 and L2 respectively. These sensors exhibit short response time (about 2 ​s) and good stability over the pH range 2.5–5.8. In addition, the present sensors show fairly good selectivity toward copper(II) ion in comparison to other common cations. Furthermore, they were satisfactorily used as indicator electrodes in complexometric titration with EDTA and for determination of copper(II) in water, tea and urine samples.

Electrochemical sensing of biotin-avidin interaction was investigated on gold electrode modified with 3-mercaptopropanoic acid (MPA) successively co-assembled with cysteamine functionalized silver nanoparticles and biotin or avidin. The stable aqueous colloid of cysteamine functionalized silver nanoparticles was synthesized successfully by well-known citric acid reduction method. Gold electrode was first modified with a monolayer of MPA by self-assembly technique. Then, cysteamine functionalized silver nanoparticles and biotin or avidin was co-assembled on the MPA modified gold electrode through an amide linkage. The stepwise modification process was optimized in terms of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurement in [Fe (CN)₆]^3−/4− redox system by varying the ratio of functionalized silver nanoparticles and biotin or avidin, viz., 1:2, 1:1, 2:1. Based on obtained results, the electrochemical sensing performances of 1:1 silver nanoparticle and biotin or avidin co-assembled gold electrode was performed by CV and EIS for varying concentration of complementary bio-affinity molecules in the same redox system. Both the CV and EIS measurements were found to have good response by resistive and capacitive changes due to coupling with a complementary biomolecule on co-assembled gold electrode. The use of avidin assembled gold electrode had led to much better response towards varying concentration of biotin over that of the biotin assembled gold electrode towards avidin.

In this study, an ion–selective electrode was developed for the potentiometric determination of strontium ions. Membrane optimization studies showed that the most suitable membrane composition was 4.0% (w/w) synthesized ionophore, 63.0% (w/w) bis(2–ethylhexyl)sebacate (BEHS), 32.0% (w/w) poly(vinyl chloride; PVC) and 1.0% (w/w) potassium tetrakis(p–chlorophenyl)borate (KTpClPB) in terms of potentiometric performance characteristics. The electrode, which exhibits a stable potentiometric behaviour, shows a linear response in the concentration range of 1.0 ​× ​10⁻⁵ – 1.0 ​× ​10⁻¹ ​mol ​L⁻¹ ​(R² ​= ​0.998). The electrode has a detection limit of 7.94 ​× ​10⁻⁶ ​mol ​L⁻¹ and a fast response time of 7s. The electrode exhibits selectivity against Sr(II) ions in the presence of some cationic species and works without being affected by pH changes in the pH range of 6.0–9.0. The proposed electrode performs the determination of Sr(II) ions in water samples with high recoveries.