Low-cost and environment-friendly synthesis of carbon nanorods assembled hierarchical meso-macroporous carbons networks aerogels from natural apples for the electrochemical determination of ascorbic acid and hydrogen peroxide

Efficient Electrochemical Microsensor for the Simultaneous Measurement of Hydrogen Peroxide and Ascorbic Acid in Living Brains

Hydrogen peroxide (H2O2) and ascorbic acid (AA), acting as two significant indicative species, correlate with the oxidative stress status in living brains, which have historically been considered to be involved mainly in neurodegenerative disorders such as Alzheimer's disease, Huntington's disease, and Parkinson's disease (PD). The development of efficient biosensors for the simultaneous measurement of their levels in living brains is vital to understand their roles played in the brain and their interactive relationship in the progress of these diseases. Herein, a robust ratiometric electrochemical microsensor was rationally designed to realize the determination of H2O2 and AA simultaneously. Therefore, a specific probe was designed and synthesized with both recognition units responsible for reacting with H2O2 to produce a detectable signal on the microsensor and linkage units helping the probe modify onto the carbon substrate. A topping ingredient, single-walled carbon nanotubes (SWCNTs) was added on the surface of the electrode, with the purpose of not only facilitating the oxidation of AA but also absorbing methylene blue (MB), prompting to read out the inner reference signal. This proposed electrochemical microsensor exhibited a robust ability to real-time track H2O2 and AA in linear ranges of 0.5-900 and 10-1000 μM with high selectivity and accuracy, respectively. Eventually, the efficient electrochemical microsensor was successfully applied to the simultaneous measurement of H2O2 and AA in the rat brain, followed by microinjection, and in the PD mouse brain.

Nitrogen Doped Porous Biochar/β-CD-MOFs Heterostructures: Bi-Functional Material for Highly Sensitive Electrochemical Detection and Removal of Acetaminophen

Acetaminophen (AC) is one of the most common over-the-counter drugs, and its pollutant in groundwater has attracted more attention due to its serious risk to human health. Currently, the research on AC is mainly focused on its detection, but few are concerned about its removal. In this work, for the first time, nitrogen-doped Soulangeana sepals derived biochar/β-cyclodextrin-Metal-organic frameworks (N-SC/β-CD-MOFs) composite was proposed for the simultaneous efficient removal and detection of AC. N-SC/β-CD-MOFs combined the properties of host-guest recognition of β-CD-MOFs and porous structure, high porosity, and large surface area of N-SC. Their synergies endowed N-SC/β-CD-MOFs with a high adsorption capacity toward AC, which was up to 66.43 mg/g. The adsorption type of AC on the surface of N-SC/β-CD-MOFs conformed to the Langmuir adsorption model, and the study of the adsorption mechanism showed that AC adsorption on N-SC was mainly achieved through hydrogen bonding. In addition, the high conductivity, large specific surface area and abundant active sites of N-SC/β-CD-MOFs were of great significance to the high-performance detection of AC. Accordingly, the sensor prepared with N-SC/β-CD-MOFs presented a wide linear range (1.0-30.0 μM) and a low limit of detection of 0.3 nM (S/N = 3). These excellent performances demonstrate that N-SC/β-CD-MOFs could act as an efficient dual-functional material for the detection and removal of AC.

Current State of Sensors and Sensing Systems Utilized in Beer Analysis

Beer is one of the most consumed beverages in the world. Advances in instrumental techniques have allowed the analysis and characterization of a large number of beers. However, review studies that outline the methodologies used in beer characterization are scarce. Herein, a systematic review investigating the molecular targets and sensometric techniques in beer characterization was performed following the PRISMA protocol. The study reviewed 270 articles related to beer analysis in order to provide a comprehensive summary of the recent advances in beer analysis, including methods using sensors and sensing systems. The results revealed the use of various techniques that include several technologies, such as nanotechnology and electronics, often combined with scientific data analysis tools. To our knowledge, this study is the first of its kind and provides the reader with a faithful overview of what has been done in the sensor field regarding beer characterization.

Highly sensitive detection of carbendazim in juices based on mung bean-derived porous carbon@chitosan composite modified electrochemical sensor

We reported a simple and scalable strategy for the preparation of mung bean-derived porous carbon@chitosan (MBC@CTS) composite, which was used to optimize the glassy carbon electrode (GCE). The MBC@CTS/GCE sensor was applied for the carbendazim (CBZ) detection. For the MBC@CTS composite, MBC with three-dimensional hierarchical structure presented large specific surface area, good adsorbability, and high electrical conductivity, while CTS had good film-forming property, hydrophilicity performance, and adhesion capacity. The MBC@CTS/GCE sensor exhibited wonderful electrochemical detection performance towards CBZ. Under the optimized conditions, the MBC@CTS/GCE sensor showed a linear concentration range from 0.1 to 20 μM with relatively low limit of detection (LOD) of 20 nM. In addition, the fabricated sensor with good reproducibility, stability, and selectivity were successfully applied for the CBZ detection in apple and tomato juices with low relative standard deviation of 2.4 %-4.2% and satisfactory recoveries of 98.8-103.2%.

Electrochemical Methods for the Analysis of Milk

The milk and dairy industries are some of the most profitable sectors in many countries. This business requires close control of product quality and continuous testing to ensure the safety of the consumers. The potential risk of contaminants or degradation products and undesirable chemicals necessitates the use of fast, reliable detection tools to make immediate production decisions. This review covers studies on the application of electrochemical methods to milk (i.e., voltammetric and amperometric) to quantify different analytes, as reported over the last 10 to 15 years. The review covers a wide range of analytes, including allergens, antioxidants, organic compounds, nitrogen- and aldehyde containing compounds, biochemicals, heavy metals, hydrogen peroxide, nitrite, and endocrine disruptors. The review also examines pretreatment procedures applied to milk samples and the use of novel sensor materials. Final perspectives are provided on the future of cost-effective and easy-to-use electrochemical sensors and their advantages over conventional methods.