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Topic Review
The Chemical Fingerprint of Fortified Wines
The chemical fingerprint of fortified wines is very complex and fascinating, being constituted by several hundred volatile and non-volatile chemical groups, such as terpenoids, pyrazines, esters, alcohols, acids, furanic compounds, phenolic compounds, and organic acids, among others. These chemical groups were present in fortified wines at different volatilities, polarities, and concentration ranges, from a few ng/L to mg/L. However, the quality of wine also depends on several parameters, such as grape variety, vineyard location, terroir, and vinification conditions (e.g., fermentation, ageing), among others. 
  • 1.7K
  • 12 Jul 2023
Topic Review
Analytical Methods for Codeine Determination
Codeine is derived from morphine, an opioid analgesic, and has weaker analgesic and sedative effects than the parent molecule. This weak opioid is commonly used in combination with other drugs for over-the-counter cough relief medication. Due to the psychoactive properties of opioid drugs, the easily obtained codeine often becomes subject to misuse. Codeine misuse has emerged as a concerning public health issue due to its associated adverse effects such as headache, nausea, vomiting, and hemorrhage. Thus, it is very important to develop reliable analytical techniques to detect codeine for both quality control of pharmaceutical formulations and identifying drug misuse in the community. This review aims to provide critical outlooks on analytical methods napplicable to the determination of codeine.
  • 1.7K
  • 11 Mar 2021
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. 
  • 1.7K
  • 28 Apr 2023
Topic Review
A Graphene-PEDOT
A graphene and poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified conductive paper-based electrochemical impedance spectroscopy (EIS) aptasensor has been successfully fabricated by a simple and continuous coating process. A graphene/PEDOT:PSS modified paper electrode forms the nanocomposite providing a conductive and sensitive substrate for further aptamer functionalization of the biosensor. This low-cost paper-based aptasensor exhibits its sensitivity to carcinoembryonic antigens (CEA) in standard buffer solutions and human serum samples in a linear range of 0.77–14 ng·mL−1. The limit of detection (LOD) is found to be 0.45 ng·mL−1 and 1.06 ng·mL−1 for CEA in both samples, separately. This aptamer-based sensing device was also evaluated and received a good correlation with the immunoassay detection method. The proposed paper-based aptasensor has demonstrated its potential as a rapid simple point-of-care analytical platform for early cancer diagnosis in less developed areas where manufacturing facilities, analytical instruments, and trained specialists are limited.
  • 1.7K
  • 01 Nov 2020
Topic Review
Cyclodextrins
Cyclodextrins (CDs) are a family of cyclic oligosaccharides artificially obtained from the union of glucose monomers linked by α-1,4 glycosidic bonds. They are shaped as truncated cones due to the constitutional asymmetry of the glucopyranose rings. Their central cavity of the cone is lined with the skeletal carbons and ethereal oxygen of the glucose residues, which produce a hydrophobic zone that is capable of forming inclusion complexes with a variety of molecules. For this reason, a number of CDs have become everyday commodities in separation sciences, and so chemical aspects such as their structures or their intercalation mode have been more profoundly studied. The structural aspects of CDs can enable the improvement of different chromatographic separations, the enhancement of sensitivity, and the accuracy of analytical methods. 
  • 1.7K
  • 08 Jan 2021
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. 
  • 1.7K
  • 01 Sep 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.
  • 1.7K
  • 16 Dec 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. 
  • 1.6K
  • 02 Jun 2023
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
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.
  • 1.6K
  • 03 Apr 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. 
  • 1.6K
  • 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.
  • 1.6K
  • 25 Aug 2022
Topic Review
Gas-Sensing Mechanisms of MXenes and MXene-Based Heterostructures
MXenes are a class of 2D transition-metal carbides, nitrides, and carbonitrides with exceptional properties, including substantial electrical and thermal conductivities, outstanding mechanical strength, and a considerable surface area, rendering them an appealing choice for gas sensors. 
  • 1.6K
  • 08 Dec 2023
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.
  • 1.6K
  • 21 Jul 2022
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).
  • 1.6K
  • 18 Sep 2021
Topic Review
Rare Earth Elements (REE)
The rare earth elements (REE) comprise a group of 16 chemically very similar elements that occur widespread in rocks, soils, and water bodies, share similar ionic radii to the essential element Ca2+, and consequently also occur in biota. Given that REE form mainly trivalent cations, they also share similarities to Al3+. Compared to their chemical cognate Ca, they have a higher reactivity. Thus, their accumulation in soils may constitute a severe environmental threat. Over the last decades, the increasing use of REE in modern technology and fertilizers raised concerns about the pollution of soils and water bodies, which led to a rapidly increasing number of publications dealing with REE toxicity to plants, animals and humans, the fate of REE in soil–plant systems, REE cycling in ecosystems and impacts of REE pollution on food security.
  • 1.6K
  • 05 Feb 2024
Topic Review
Polyphenols Analysis in Plants Matrices
Phenolic compounds are plants’ bioactive metabolites that have been studied for their ability to confer extensive benefits to human health. As currently there is an increased interest in natural compounds identification and characterization, new analytical methods based on advanced technologies have been developed. 
  • 1.6K
  • 27 May 2021
Topic Review
Analytical Techniques for Detection and Quantification of PFAS
The established methods for performing poly-fluoroalkyl substances (PFAS) analysis are based on Liquid Chromatography-Mass Spectrometry (LC-MS). Both the sample preparation and the development of the chromatographic set-up are crucial steps for reliable, precise, and accurate measurements. According to the literature, the conventional reverse phase separation stationary phase column is the most widely utilized approach. To improve the chromatographic performance, columns equipped with polar functionalized C18 alkyl chains were introduced.
  • 1.6K
  • 21 Jun 2023
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
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
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