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Topic Review
Paper-Based Analytical Devices for Colorimetric
The so-called paper-based analytical devices (PADs) have arisen as an efficient, affordable, user-friendly, rapid, and equipment-free technology that is available to citizens. The development of PADs in areas such as clinical diagnostics, food safety and environmental monitoring, etc., as well as fabrication methods, target analytes and analytical performance, has been extensively reviewed during the last decade, with the scientific community showing great interest toward these appealing analytical approaches.
  • 1.6K
  • 06 Dec 2021
Topic Review
Chemical Analysis of Synthetic Antioxidants in Foodstuffs
The information obtained by the systematic search in ScienceDirect® databases, indicated the predominance of the use of separation chromatography, followed by detection techniques in the development of analytical methods for the detection of phenolic antioxidants in foodstuffs. This is because these techniques allow the simultaneous determination of different types of antioxidants, through the separation of these compounds at different stages of a column, thus obtaining different retention times, which are related to the physicochemical characteristics of the antioxidants and their interaction between the stationary and mobile phase. After the separation, the antioxidants are identified and quantified using specific chromatographic detectors, such as ultraviolet–visible, diode array, thermal conductivity, and mass spectroscopy, resulting in a suitable sensitivity and selectivity. However, separation and detection chromatographic, despite being very accurate in the detection of antioxidants, have as their main disadvantage the use of large amounts of organic solvents or inert gases, with elevated purity and, consequently, high cost. Additionally, the use of these techniques requires rigorous steps of extraction and cleanup to prepare the foodstuff samples for analysis, remove interference compounds, and/or preconcentrate the antioxidants to obtain reliable information. Extraction steps can increase the time and costs in the analysis, promote a reduction in the analytical frequency, and generate a great quantity of residues, which goes against a very important principle, taken very seriously today, green chemistry, which orients the reduction or elimination of toxic residues in chemical products and processes, including all cycles of a chemical, in its design, manufacture, use, and final disposal.
  • 1.6K
  • 04 Nov 2022
Topic Review
Derivatization Strategies in Flavor Analysis
Wine and beer are the most appreciated and consumed beverages in the world. This success is mainly due to their characteristic taste, smell, and aroma, which can delight consumer’s palates. These olfactory characteristics are produced from specific classes of volatile compounds called “volatile odor-active compounds” linked to different factors such as age and production. Given the vast market of drinking beverages, the characterization of these odor compounds is increasingly important. However, the chemical complexity of these beverages has led the scientific community to develop several analytical techniques for extracting and quantifying these molecules. Even though the recent “green-oriented” trend is directed towards direct preparation-free procedures, for some class of analytes a conventional step like derivatization is unavoidable.
  • 1.6K
  • 16 Dec 2022
Topic Review
Advances of MXenes
MXenes are synthesized from ‘MAX’ phases by the selective etching of ‘A’ layers. The MAX phases are conductive 2D layers of transition metal carbides/nitrides interconnected by the ‘A’ element with strong ionic, metallic, and covalent bonds.
  • 1.6K
  • 04 Jul 2022
Topic Review
Mechanisms of Graphene-Based Humidity Sensors
Humidity sensors are a common type of sensors in our daily life, and play a significant role in numerous application fields ranging from humidity control for various kinds of industrial processing, agricultural moisture monitoring, and medical fields to weather forecasting, indoor humidity sensing, and domestic machine controlling, and the corresponding research has continued for more than 100 years since the 18th century. Principally, water molecules in the gas environment will adsorb onto the graphene surfaces in a graphene-based humidity sensor, which causes changes of some properties of the graphene materials, corresponding to the humidity change. Various kinds of graphene-based humidity sensors have been developed according to different sensing mechanisms or sensor configurations. This part briefly introduces seven types of sensing mechanisms commonly applied in the graphene-based humidity sensors, and the reviews on progresses of graphene-based humidity sensors working in the last three mechanisms, i.e. SAW, QCM, and optical fiber, are also included.
  • 1.6K
  • 14 Jan 2022
Topic Review
The SIFT-MS Technique
Selected ion flow tube mass spectrometry (SIFT-MS) uses soft chemical ionization (CI) to generate mass-selected reagent ions that can rapidly react with and quantify VOCs down to part-per-trillion concentrations (by volume, pptV). Up to eight reagent ions (H3O+, NO+, O2+, O-, OH-, O2-, NO2- and NO3-) obtained from a microwave discharge in air are available on SIFT-MS instruments. These reagent ions react with VOCs and other trace analytes in well-controlled ion-molecule reactions, but they do not react with the major components of air (N2, O2, CO2 and Ar). This enables direct, real-time analysis of air samples to be achieved at trace and ultra-trace levels without pre-concentration. Rapid switching between reagent ions provides high selectivity because the multiple reaction mechanisms give independent measurements of each analyte. 
  • 1.6K
  • 28 Apr 2023
Topic Review
MOS Sensors for Detecting Chemical Warfare Agents
On-site detection of chemical warfare agents (CWAs) can be performed by various analytical techniques. Devices using well-established techniques such as ion mobility spectrometry, flame photometry, infrared and Raman spectroscopy or mass spectrometry (usually combined with gas chromatography) are quite complex and expensive to purchase and operate. For this reason, other solutions based on analytical techniques well suited to portable devices are still being sought. Analyzers based on simple semiconductor sensors may be a potential alternative. In sensors of this type, the conductivity of the semiconductor layer changes upon interaction with the analyte. Metal oxides (both in the form of polycrystalline powders and various nanostructures), organic semiconductors, carbon nanostructures, silicon and various composites that are a combination of these materials are used as a semiconductor material. Due to the fact that the dominant group of semiconductor resistive sensors is metal oxide semiconductors (MOS sensors), it will be the focus herein.
  • 1.5K
  • 03 Apr 2023
Topic Review
L-Dopa Extraction and Analytical Determination in Plant Matrices
L-dopa is a precursor of dopamine used as the most effective symptomatic drug treatment for Parkinson’s disease. Most of the L-dopa isolated is either synthesized chemically or from natural sources, but only some plants belonging to the Fabaceae family contain significant amounts of L-dopa. Due to its low stability, the unambiguous determination of L-dopa in plant matrices requires appropriate technologies. Several analytical methods have been developed for the determination of L-dopa in different plants. The most used for quantification of L-dopa are mainly based on capillary electrophoresis or chromatographic methods, i.e., high-performance liquid chromatography (HPLC), coupled to ultraviolet-visible or mass spectrometric detection. HPLC is most often used. 
  • 1.5K
  • 01 Sep 2022
Topic Review
Separation of Chlorophylls and Chlorophyllins in Food Products
Chlorophyll is a natural green hue with a tetrapyrrole ring system with different substituents. 
  • 1.5K
  • 02 Jun 2023
Topic Review
Microextraction Techniques in Lipid Peroxidation Product Detection
Lipid peroxidation, the most aggressive reaction in food, results in the formation of reactive organic compounds that detrimentally impact food sensory qualities and consumers’ health. While controlled lipid peroxidation can enhance flavors and appearance in certain foods, secondary peroxidation products lead to sensory deterioration in a variety of products, such as oils, alcoholic beverages, and meat. Dispersive liquid-liquid microextraction (DLLME), solid-phase microextraction (SPME), and gas-diffusion microextraction (GDME). These techniques offer efficient and sensitive approaches to extracting and quantifying lipid oxidation products and contribute to the understanding of oxidative deterioration in various food products. 
  • 1.5K
  • 26 Oct 2023
Topic Review
Advanced Mass Spectrometry in Service of Forensic Analysis
Mass spectrometry has been used to assist forensic investigation. Due to its unique capabilities, mainly high-resolution mass data and structural information, high sensitivity, and cooperation with separation techniques, this method provides access to many tools streamlining and accelerating sample analysis. Low analyte consumption, advanced derivatization procedures and availability of isotopically labeled standards offer opportunities to study materials previously not considered viable evidence, opening new avenues in forensic investigations.
  • 1.5K
  • 25 Aug 2022
Topic Review
Bioactive Peptides in Dairy Products
All the research pertaining to the detection and identification of minute peptides (<4 amino acids) present in multifarious mixtures are in their early stages because of a lack of stringent peptide identification methodologies. Precise amendments like discerned censoring of ions against previously identified sequences of peptides can help overcome the aforementioned issues faced at times of optimization procedures during or after MS analysis. A state-of-the-art genesis in structure-informedpeptide identification and quantification methodologies can be guaranteed by added enrichment in the sensitivity and resolving capacity of MS, in conjunction with novel cutting edge ionization techniques. Modernization of the software for foodomics and peptidomics research and peptide identification is needed. Also, explicit and coherent structure identification in common and especially in synchronization with LC-MS requires significant attention. A continuous focus will be given to understanding of the biochemical functions of milk ingredients and their dietary implications by using a variety of powerful tools like -omics, cell models, gut microbiome research and imaging. The introduction of innovative facilities including is an absolute requirement for the development of approaches, such as proteomics, recombinant enzymes and microbial fermentation to study and improve the metabolic and health consequences of the various roles of bioactive peptides throughout the expression of genes. Consequently, the formulation of products incorporating bioactive peptides should examine the allergenicity, toxicity and stability of the a ected metabolic functions during gastrointestinal digestion. Despite considerable progress in the isolation, purification and assessment of bioactivities of BP from various natural sources, several hurdles still remain to be overcome, particularly technological advancements to produce them on a broad scale without losing activity. In conclusion, milk-derived bioactive peptides o er substantial future prospects for product development to support health, with their multifunctional assets.  
  • 1.5K
  • 30 Apr 2021
Topic Review
Grapevine Cane Extracts
Grapevine canes are viticulture waste that is usually discarded without any further use. However, recent studies have shown that they contain significant concentrations of healthpromoting compounds, such as stilbenes, secondary metabolites of plants produced as a response to biotic and abiotic stress from fungal disease or dryness. Stilbenes have been associated with antioxidant, anti‐inflammatory, and anti‐microbial properties and they have been tested as potential treatments of cardiovascular and neurological diseases, and even cancer, with promising results. Stilbenes have been described in the different genus of the Vitaceae family, the Vitis genera being one of the most widely studied due to its important applications and economic impact around the world. This entry presents an in‐depth study of the composition and concentration of stilbenes in grapevine canes. The results show that the concentration of stilbenes in grapevine canes is highly influenced by the Vitis genus and cultivar aspects (growing conditions, ultraviolet radiation, fungal attack, etc.). Different methods for extracting stilbenes from grapevine canes have been reviewed, and the extraction conditions have also been studied, underlining the advantages and disadvantages of each technique. After the stilbenes were extracted, they were analyzed to determine the stilbene composition and concentration. Analytical techniques have been employed with this aim, in most cases using liquid chromatography, coupled with others such as mass spectrometry and/or nuclear magnetic resonance to achieve the individual quantification. Finally, stilbene extracts may be applied in multiple fields based on their properties. The five most relevant are preservative, antifungal, insecticide, and biostimulant applications. The current state‐of‐the‐art of the above applications and their prospects are discussed.
  • 1.5K
  • 11 Sep 2020
Topic Review
Flow analysis by Capillary Electrophoresis
Flow analysis is the science of performing quantitative analytical chemistry in flowing streams. Capillary electrophoresis (CE) is an analytical method that separates ions in a narrow channel. Separation is based on ions electrophoretic mobility with the use of an applied voltage. Because of its efficiency and speed of analysis, capillary electrophoresis (CE) is a prospective method for the monitoring of a flow composition withdrawn from various processes (e.g., occurring in bioreactors, fermentation, enzymatic assays, and microdialysis samples).
  • 1.5K
  • 18 Sep 2021
Topic Review
Stability of Cu-Based Catalysts for Methanol Reforming
The stability of copper-based catalysts is an important property that affects the catalytic efficiency, which determines the service life of the catalytic base in the methanol steam reforming (MSR) reaction, and plays an important role in the sustainable production of hydrogen.
  • 1.5K
  • 21 Jul 2022
Topic Review
Determination of Psychoactive Drugs in Air
Understanding of the levels of psychoactive drugs in air is important for assessing both occupational and environmental exposure. Intelligence on the usage and manufacture of illegal drugs can also be gained. Environmental analysis and determination of air quality has recently expanded from its traditional focus to new pollutant categories that include illicit and psychoactive drugs. 
  • 1.5K
  • 22 Feb 2022
Topic Review
HR-MAS NMR in Plant Metabolomics
Metabolomics is used to reduce the complexity of plants and to understand the underlying pathways of the plant phenotype. The metabolic profile of plants can be obtained by mass spectrometry or liquid-state NMR. Extraction of metabolites from the sample is necessary for both techniques to obtain the metabolic profile. This extraction step can be eliminated by making use of high-resolution magic angle spinning (HR-MAS) NMR which allows to get metabolic profile directly in intact plant tissues such as intact leaves. An HR-MAS NMR-based metabolomics workflow is thus established that provide a novel platform for obtaining important information of regular metabolic network non-invasively.
  • 1.5K
  • 14 Jul 2021
Topic Review
Molecularly Imprinted Polymers in Sample Preparation
Molecularly Imprinted Polymers (MIPs) are synthetic polymeric materials with imprinted sites complementary to a specific molecule and high affinity over analytes with analogous molecular structure. Extraction can benefit from the production of MIPs that can be applied as sorbents for the extraction of specific antibiotics. 
  • 1.5K
  • 17 Jul 2023
Biography
Victoria Samanidou
Dr Victoria Samanidou is Full Professor and Director of the Laboratory of Analytical Chemistry in the Department of Chemistry of Aristotle University of Thessaloniki, Greece. Her research interests focus on the development of sample preparation methods using sorptive extraction prior to chromatographic analysis. She has co-authored 202 original research articles in peer reviewed journals and
  • 1.5K
  • 19 Aug 2022
Topic Review
Capacitive Field-Effect Bio-Chemical Sensors
       Electrolyte-insulator-semiconductor (EIS) field-effect sensors belong to a new generation of electronic chips for biochemical sensing, enabling a direct electronic readout. The review gives an overview on recent advances and current trends in the research and development of chemical sensors and biosensors based on the capacitive field-effect EIS structure—the simplest field-effect device, which represents a biochemically sensitive capacitor. Fundamental concepts, physicochemical phenomena underlying the transduction mechanism and application of capacitive EIS sensors for the detection of pH, ion concentrations, and enzymatic reactions, as well as the label-free detection of charged molecules (nucleic acids, proteins, and polyelectrolytes) and nanoparticles, are presented and discussed.
  • 1.5K
  • 19 Apr 2022
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