Nowadays, micro-sized sensors have become a hot topic in electroanalysis. Because of their excellent analytical features, microelectrodes are well-accepted tools for clinical, pharmaceutical, food safety, and environmental applications. In this brief review, we highlight the state-of-art electrochemical non-enzymatic microsensors for quantitative detection of ascorbic acid (also known as vitamin C). Ascorbic acid is a naturally occurring water-soluble organic compound with antioxidant properties and its quantitative determination in biological fluids, foods, cosmetics, etc., using electrochemical microsensors is of wide interest. Various electrochemical techniques have been applied to detect ascorbic acid with extremely high sensitivity, selectivity, reproducibility, and reliability, and apply to in vivo measurements. This review paper aims to give readers a clear view of advances in areas of electrode modification, successful strategies for signal amplification, and miniaturization techniques used in the electroanalytical devices for ascorbic acid. In conclusion, current challenges related to the microelectrodes design, and future perspectives are outlined.

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered. Keywords: biosynthesis; green synthesis; nanomaterials; nanotechnology; modified electrodes

Reliable, rapid, highly selective and sensitive analytical methods for the determination of antineoplastic agent 5-fluorouracil (5-FU) in human body fluids (blood serum/plasma and urine) are required to improve the chemotherapy regimen to reduce its toxicity and improve efficacy. Nowadays, electrochemical techniques provide a powerful analytical tool for 5-FU detection systems. This comprehensive review covers the advances in the development of electrochemical sensors for the quantitative determination of 5-FU, mainly focused on original studies reported from 2015 to date. We have summarized recent trends in the electrochemical sensor systems applied for the analysis of 5-FU in pharmaceutical formulations and biological samples, and critically evaluated the key performance metrics of these sensors (limit of detection, linear range, stability and recovery). Challenges and future outlooks in this field have also been discussed.

Ruthenium oxide hexacyanoferrate (RuOHCF) film was electrochemically deposited onto a glassy carbon (GC) surface using consecutive cyclic voltammetry as a facile and green synthetic strategy. The electrochemical behaviour and electrocatalytic properties of the modified electrode RuОHCF/GC were evaluated with regards to electroreduction of hydrogen peroxide and iodate in a strong acidic medium (pHs 1.0–2.0) by using different electrochemical techniques, including cyclic voltammetry and amperometry at a constant potential. Electrochemical studies indicated that RuОHCF/GC possess a high catalytic activity in both studied reactions, fast response and good reproducibility of the current signal. The RuОHCF/GC exhibits enhanced electrocatalytic behaviour compared with other modified electrodes reported before. The simple and reproducible procedure for electrode fabrication, the wide linear range, anti-interference performance and long-time stability of the RuОHCF/GC make it a promising sensing material for practical quantitative determination of hydrogen peroxide and iodate. Remarkably, the reported modified electrode provided superior sensitive (1050 μA mM–1 cm–2) and highly selective amperometric detection of iodate.

Due to the rapid growth of the cosmetic industry in recent years, the development of new, reliable, cost-effective, ease of use and rapid methods to assay cosmetics’ quality is of particular importance. Modern electrochemistry provides powerful analytical techniques with excellent sensitivity, instrumental simplicity and portability, providing reliable alter­natives to conventional analytical methods. This review aims to give readers a clear view of advances in areas of electrode modification, successful strategies for signal amplification, and miniaturization techniques used in electro­analytical devices for cosmetics control and safety. We have summarized recent trends in the nonenzymatic electrochemical sensor sys­tems applied in the analysis of cosmetic products revealing that there are a variety of ef­ficient sensors for whitening agents, preservatives, UV filters, heavy metals, etc. In con­clu­sion, current challenges related to the sensors design and future perspectives are outlined.