Analytical & Bioanalytical Electrochemistry
Volume:14 Issue: 11, Nov 2022

Several morphologically different Cu-oxide nanocrystals (cube, exposing only the (100) facets; elongated octahedron, exposing only the (111) facets; normal octahedron, exposing only the (111) facets; rounded octahedron, exposing only the (111) facets; truncated edge cube, exposing the (100), (110), and (111) facets) have been prepared. Mixed oxidation state facets were obtained, with the X-ray Photoelectron Spectroscopy revealing that both CuI and CuII are present in the samples. The % CuI and CuII vary for the different morphologies. Morphologies exposing the (111) facet showed the highest % CuI present, with the morphologies exposing the (100) facet showing the least amount of CuI. The glassy carbon electrode’s surface was modified with these Cu-oxide nanocrystals and their sensing performance for glucose detection was investigated. The limits of detection (LOD) observed for all the Cu-oxide nanocrystal electrodes were < 2 μM. Electrodes modified with Cu-oxide nanocrystals exposing the (111) facets and having more CuI present in the sample resulted in better glucose detection limits.

The present work has been focused on the removal of fluoride from aqueous solutions through the electrocoagulation process. This work aimed to assess the efficiency of electrodes and electrocoagulation process in fluoride removal from aqueous solutions. Batch experiments were carried out using monopolar Iron and Copper electrodes as anode and cathode. Fluoride removal were influenced by operating variables such as current density, nature of electrodes, initial fluoride concentration and NaCl amount which have significant effects on removal efficiency. Indeed, the increase of current density from 0.18 to 27.8 mA/cm2, fluoride removal efficiency increased from 61 to 98% using Fe electrodes while 57 to 63% using Cu electrodes during the electrolysis time indicating the high capacity of Fe electrodes for fluoride removal. The addition of NaCl solution increased the fluoride removal efficiency from 65% to 70% using Fe electrodes. Kinetics modelling revealed that Fluoride was removed on the surface of Fe electrodes following a pseudo-second order kinetic while pseudo-first order kinetic using Cu electrodes. Maximum energy consumption was 70 kWh/m3 with water containing 0.5 g/L of NaCl while an energy of 45 kWh/m3 for water without NaCl. Consequently, electrocoagulation technology is a promising method for defluoridation of water using iron electrodes.

The limit of detection (LOD) is defined as the lowest quantity or concentration of a component that can be reliably distinguished from the limit of blank (LOB). LOD value is one of the most important parameters considered for many determination methods and is usually calculated on the linear correlation between signal and concentration. However, the linear correlation may not always be obtained in experimental studies. We claim that data with low linear correlation have meaning, and we present such a study because analytical studies based on these data are not easily understood in the literature. In this manuscript, we suggest that a calibration curve can be obtained from nonlinear data points and the LOD value can be calculated. We tested this approach for the determination of exosomes and supported it with mathematical calculations. We produced a label-free sensor using anti-CD63 on the gold electrode for selective and reliable impedimetric detection of the exosomes obtained from Colo 320 cell lines in data points that are high concentrations and out of linearity. We characterized in detail what each calculation means. This sensor with a LOD value of 3.90×1011 exosome particles µL-1 and with a cubic polynomial model for the calibration curve was considered sensitive and reliable, especially for high vesicle content of samples such as cell culture medium.

Metal packaging is excellent for storing canned foods. However, due to the acidic nature of the canning solution, the contact of the food with the metal container diminishes its shelf life, and can produce a corrosion problem. The inhibiting effect of olive leaf extract on tin corrosion in 3 wt% acetic acid was examined in this study. The impact of the concentration of inhibitor (0.1–1g/L), immersion time (0.5–12h), and temperature (20–50°C) were investigated employing a statistical approach based on the design of experiment (DOE). For those three factors, response surface methodology (RSM) using face-centered central composite design (FCCD) was chosen and applied to the design matrix. A potentiodynamic polarization (PDP) test was used to assess the output corrosion current density (icorr) under various conditions specified in the design matrix. The model proved correct with a good coefficient of determination of (R² = 97.84%). The outcomes of the PDP method demonstrate that the corrosion current density rises with temperature, indicating that physisorption is the dominant mechanism.

Male development is greatly influenced by testosterone, which also helps to build bone and muscle, as well as the testis, penis, and prostate.  Endocrinology relies heavily on hormone and related biomarkers measurements. Chromatographic techniques are commonly used to analyze hormones because they offer excellent separation and quantification capabilities. Due to their usability, portability, simplicity, and sensitivity, electrochemical biosensors have grown more and more in popularity over time for hormone detection. Electrochemical biosensors are divided into four groups: impedimetric, potentiometric, amperometric, and conductometric. Biosensors based on electrochemistry are ideal for early clinical analysis, but their commercialization is hindered by poor reproducibility. An overview of electrochemical biosensors that detect testosterone hormones is presented in our review. After an introduction to biosensors and electrochemical biosensors, testosterone hormone, the immobilization process and analytical performance of the electrochemical biosensors will be discussed. The linear ranges, the limits of detection, reproducibilities, and regenerations of developed biosensors are discussed in this paper.

Given the importance of La3+ ions in various areas of medicine and industry and the effects these ions can have on humans and animals, the analysis of the species is an important area in analytical chemistry. In the light of the efficiency of the ion-selective electrodes in the determinations of traces amounts of various analytes, including rare earth ions and lanthanum, all published reports on the development of La3+ ions were reviewed with a focus on the ionophores incorporated therein, their composition and the response and selectivity behavior of the developed sensors, to provide the readers with insight on the various factors influencing the analytical performance of lanthanum selective sensors ions, which can also be applied to research on the development of other rare earth ion sensors.