Highly sensitive voltammetric determination of Allura Red (E129) food colourant on a planar carbon fiber sensor modified with shungite.

This article presents an original planar carbon fiber electrode (PCFE), in which shungite (SHU) is used as a modifier for the first time. Shungite is a unique natural nanostructured composite consisting of carbon in the form of aggregated graphene stacks, oxides of silicon, titanium, aluminum, iron, magnesium, potassium, etc. Macro- and micro-elements, biologically active components that are present in shungite provide it with attractive antioxidant properties, make it a biocompatible and environmentally friendly material that meets the principles of green chemistry.

Biosensors Based on Phenol Oxidases (Laccase, Tyrosinase, and Their Mixture) for Estimating the Total Phenolic Index in Food-Related Samples.

Plant phenolic compounds demonstrate bioactive properties in vitro and/or in vivo, which creates demand for their precise determination in life sciences and industry. Measuring the concentration of individual phenolic compounds is a complex task, since approximately 9000 plant phenolic substances have been identified so far. The determination of the total phenolic content (TPC) is less laborious and is used for the qualimetric evaluation of complex multicomponent samples in routine analyses.

Carbon Paper Modified with Functionalized Poly(diallyldimethylammonium chloride) Graphene and Gold Phytonanoparticles as a Promising Sensing Material: Characterization and Electroanalysis of Ponceau 4R in Food Samples.

This paper presents a novel eco-friendly sensing material based on carbon paper (CP) volumetrically modified with a composite nanomodifier that includes functionalized poly(diallyldimethylammonium chloride) graphene (PDDA-G) and phytosynthesized gold nanoparticles (phyto-AuNPs). The functionalization of graphene was justified by Fourier-transform infrared spectroscopy. The phyto-AuNPs (d = 6 nm) were prepared by "green" synthesis with the use of strawberry leaf extract.

Electrochemical Properties of Phytosynthesized Gold Nanoparticles for Electrosensing.

Gold nanoparticles are widely used in electrosensing. The current trend is to phytosynthesize gold nanoparticles (phyto-AuNPs) on the basis of the "green" chemistry approach. Phyto-AuNPs are biologically and catalytically active, stable and biocompatible, which opens up broad perspectives in a variety of applications, including tactile, wearable (bio)sensors.

Developing Activated Carbon Veil Electrode for Sensing Salivary Uric Acid.

The paper describes the development of a carbon veil-based electrode (CVE) for determining uric acid (UA) in saliva. The electrode was manufactured by lamination technology, electrochemically activated and used as a highly sensitive voltammetric sensor (CVE). Potentiostatic polarization of the electrode at 2.

The Effect of the Antioxidant Activity of Plant Extracts on the Properties of Gold Nanoparticles.

Synthesis of gold nanoparticles (phyto-AuNPs) with the use of leaf extracts (phytosynthesis) is based on the concept of Green Chemistry. The present study is conducted to discuss how antioxidant activity (AOA) of extracts from plant leaves impacts on the kinetics of phytosynthesis, the size of the formed nanoparticles, and the stability of their nanosuspensions. Results show that the formation rate of phyto-AuNPs suspensions accelerate due to the increase in the AOA of the extracts.

Contact hybrid potentiometric method for on-site and in situ estimation of the antioxidant activity of fruits and vegetables.

A new version of the hybrid potentiometric method (HPM) for evaluating the antioxidant activity (AOA) of fruits and vegetables, which we called contact (CHPM), is proposed. A screen-printed electrode pair coated by a membrane impregnated with a mediator serves as a sensor system. The potential shift, which is observed when the sensor system is exposed to the sample slice is used as a source of information.

Disposable Potentiometric Sensory System for Skin Antioxidant Activity Evaluation.

The skin is a natural barrier between the external and internal environment. Its protective functions and the relationship of its state with the state of health of the organism as a whole are very important. It is known that oxidant stress (OS) is a common indicator of health status.

Potentiometric method of plant microsuspensions antioxidant activity determination.

This paper focuses on the development of a simple, fast and reliable technique of sample preparation to be employed as part of potentiometric measurements of plant total antioxidant activity (AOA). Plant extracts and plant microsuspensions were analysed. The conditions for obtaining plant extracts were chosen: they exhibited the highest antioxidant activity at +80 °C and extraction time 20 min.