An Electrochemical Sensor of Theophylline on a Boron-Doped Diamond Electrode Modified with Nickel Nanoparticles.

Theophylline is a drug with a narrow therapeutic range. Electrochemical sensors are a potentially effective method for detecting theophylline concentration to prevent toxicity. In this work, a simple modification of a boron-doped diamond electrode using nickel nanoparticles was successfully performed for a theophylline electrochemical sensor. The modified electrode was characterized using a scanning electron microscope and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry methods were used to study the electrochemical behavior of theophylline. The modified nickel nanoparticles on the boron-doped diamond electrode exhibited an electrochemically active surface area of 0.0081 cm2, which is larger than the unmodified boron-doped diamond's area of 0.0011 cm2. This modified electrode demonstrated a low limit of detection of 2.79 µM within the linear concentration range from 30 to 100 µM. Moreover, the modified boron-doped diamond electrode also showed selective properties against D-glucose, ammonium sulfate, and urea. In the real sample analysis using artificial urine, the boron-doped diamond electrode with nickel nanoparticle modifications achieved a %recovery of 105.10%, with a good precision of less than 5%. The results of this work indicate that the developed method using nickel nanoparticles on a boron-doped diamond electrode is promising for the determination of theophylline.

Finger-Actuated Micropump of Constant Flow Rate without Backflow.

This paper presents a finger-actuated micropump with a consistent flow rate and no backflow. The fluid dynamics in interstitial fluid (ISF) extraction microfluidics are studied through analytical, simulation, and experimental methods. Head losses, pressure drop, diodocity, hydrogel swelling, criteria for hydrogel absorption, and consistency flow rate are examined in order to access microfluidic performance. In terms of consistency, the experimental result revealed that after 20 s of duty cycles with full deformation on the flexible diaphragm, the output pressure became uniform and the flow rate remained at nearly constant levels of 2.2 µL/min. The flow rate discrepancy between the experimental and predicted flow rates is around 22%. In terms of diodicity, when the serpentine microchannel and hydrogel-assisted reservoir are added to the microfluidic system integration, the diodicity increases by 2% (Di = 1.48) and 34% (Di = 1.96), respectively, compared to when the Tesla integration (Di = 1.45) is used alone. A visual and experimentally weighted analysis finds no signs of backflow. These significant flow characteristics demonstrate their potential usage in many low-cost and portable microfluidic applications.

Ionic Liquid-Based Gels for Applications in Electrochemical Energy Storage and Conversion Devices: A Review of Recent Progress and Future Prospects.

Ionic liquids (ILs) are molten salts that are entirely composed of ions and have melting temperatures below 100 °C. When immobilized in polymeric matrices by sol-gel or chemical polymerization, they generate gels known as ion gels, ionogels, ionic gels, and so on, which may be used for a variety of electrochemical applications. One of the most significant research domains for IL-based gels is the energy industry, notably for energy storage and conversion devices, due to rising demand for clean, sustainable, and greener energy. Due to characteristics such as nonvolatility, high thermal stability, and strong ionic conductivity, IL-based gels appear to meet the stringent demands/criteria of these diverse application domains. This article focuses on the synthesis pathways of IL-based gel polymer electrolytes/organic gel electrolytes and their applications in batteries (Li-ion and beyond), fuel cells, and supercapacitors. Furthermore, the limitations and future possibilities of IL-based gels in the aforementioned application domains are discussed to support the speedy evolution of these materials in the appropriate applicable sectors.

Further Study of CO2 Electrochemical Reduction on Palladium Modified BDD Electrode: Influence of Electrolyte.

The study of CO2 electrochemical reduction to useful compounds using bare or modified BDD electrode attracts numerous attentions. Meanwhile, the efficiency of products obtained from CO2 electrochemical reduction is known to be determined by the electrode material and the electrolyte. Formic acid as main product and CO as a minor product, have also been known on the CO2 reduction using BDD electrode. Recently, we reported the successful improvement of CO production from the reduction of CO2 by decorating the surface of BDD electrode with palladium particles. Following this, herein, we present further investigation on electrolyte dependence, including cation and anion dependence and also concentration effect in order to understand deeply the CO2 reduction on surface of palladium modified BDD electrode. The results suggest the use of NaCl and KCl as a catholyte for optimum performance, in addition to the improvement of CO2 reduction product in higher electrolyte concentration.

Electrochemical reduction of CO2 using palladium modified boron-doped diamond electrodes: enhancing the production of CO.

In recent years, boron-doped diamond (BDD) has been utilized as an electrode for the electrochemical reduction of CO2, and several reports have been published on this. The wide potential window of BDD enables the hydrogen evolution reaction, which competes with CO2 reduction, to be suppressed. On the other hand, the high overpotential is still a problem. We attempted to overcome this problem by depositing metal on the BDD electrode. Pd metal was chosen to modify the surface of the BDD electrode (PdBDD). Employing this electrode at a lower potential of -1.6 V vs. Ag/AgCl, we increased the production of CO (53.3% faradaic efficiency) from the reduction of CO2. We present various attempts made to improve the CO production.