Uric acid is one of the most important metabolites as its blood levels can help to diagnose important diseases. Tradicionally, uric acid is determined by enzymatic-spectrophotometric techniques, but in recent years new promising alternatives have arisen. This review is devoted to the development over the past decade of non-enzymatic electrochemical studies based on nano-structures of non-noble metal oxides (Fe2O3, CuO, Cu2O, ZnO, NiO, MnO2, CeO2, MgO, SnO2 and Co3O4) for uric acid detection. The proposals showed the application of electrochemical sensors for the determination of uric acid in blood, urine, pharmaceuticals, water, and commercial shellfish. The developed electrodes are based on vitreous carbon electrodes, carbon paste, or screen-printed, mainly modified with nano-structures of metal oxides to electrochemically oxidize uric acid, where the anodic current peak is used as the analytical signal and the results reported are very promising.
Uric acid is an important metabolite as its blood levels can help diagnose significant diseases. The accepted methodology for quantifying uric acid is based on enzymatic-spectrophotometric techniques, but in recent years, new alternatives have emerged. Electroanalytical strategies have emerged as promising alternatives for the accurate and precise determination of uric acid. This review analyzes the development over the last decade of non-enzymatic electrochemical studies based on Metal-Organic Frameworks (MOFs) for the detection of uric acid. MOFs have recently arisen as new materials for the electrochemical determination of organic molecules of biomedical interest. Most of the proposals in the literature reported applications of these sensors for the determination of uric acid in blood, urine, and pharmaceutical products. Vitreous carbon and carbon paste electrodes are the main transductors modified with MOF materials to electro-oxidize uric acid; the maximum anodic peak current is then used as the analytical signal. The reported results are promising, demonstrating that this electroanalytical approach represents a viable alternative for fast and confident analysis of this molecule.
Fe2O3 nanoparticles have interesting properties such as low production cost, chemical stability, biocompatibility, poor toxicity, and high conductivity. In this work, Fe2O3 nanoparticles are used as modifiers to combine their characteristics to those of carbon paste electrodes to enhance the determination of glucose. Differential pulse voltammetry was used as the quantitative analytical technique and then a Box-Behnken design was used to optimize the variables in order to maximize the glucose electro-oxidation response signal. The Fe2O3-NPs/CPE sensor showed excellent electro-catalytic performance toward glucose oxidation and three linear ranges: 0.015 µM – 1 µM (sensitivity of 51.54 µA/ µM), 1 µM – 100 ¬ µM (sensitivity of 4.21 µA/ µM) and, 30 µM – 700 µM (sensitivity of 0.041 µA/µM) and detection limit of 0.044 µM. The sensor also presented good reproducibility and repeatability, excellent selectivity (in the presence of ascorbic acid, uric acid, lactose, caffeine, and paracetamol), and satisfactory applicability for glucose detection in commercial electrolyte beverages and human urine samples. The improved electrochemical detection capability of Fe2O3-NPs/CPE is attributed to the formation of Fe4+=O reactive groups at alkaline pH that allowed the oxidization of glucose by a nonenzymatic mechanism.
Glucose is the principal source of energy for humans and its quantification in physiological samples can diagnose or prevent diseases. Commonly, glucose determination is based on spectrophotometric-enzymatic techniques, but at least since a decade ago, electroanalytical strategies have emerged as promising alternatives providing accuracy and precision in the determination of biomolecules. This review focuses on the development of non-enzymatic methodologies based on modified electrochemical sensors with Metal-Organic Frameworks (MOF) for glucose detection sensors in physiological samples (blood and urine). Glassy carbon electrodes (GCE), carbon paste electrodes (CPE), and screen-printed electrodes (SPE) are the main transductors modified with MOF for the electrochemical oxidation of glucose, and the maximum anodic peak current is taken to the analytical signal. The reported results demonstrated that this electroanalytical approach represents a viable alternative for fast and confident analysis of the glucose molecule.
In this work, Fe2O3 nanoparticles were used for the construction of a modified carbon paste electrode for the electrochemical determination of glucose in an alkaline solution. Differential pulse voltammetry (DPV) was used as a quantitative analytical technique and a Box-Behnken design to optimize the variables related to this technique. The Fe2O3-NPs/CPE sensor showed excellent electro-catalytic performance towards glucose oxidation with a wide linear range of 0.0003 mM - 0.7 mM, a detection limit of 4.42x10-5 mM, and a quantification limit of 1.47x10-4 mM. The sensor also showed good reproducibility and repeatability, excellent selectivity (in the presence of ascorbic acid, uric acid, lactose, caffeine, and paracetamol), and satisfactory applicability for glucose detection in commercial electrolyte drink and human urine samples. Fe2O3 nanostructures are promising for the development of effective non-enzymatic electrochemical sensors for glucose determination in complex samples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.