You're using an outdated browser. Please upgrade to a modern browser for the best experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
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. 
  • 1.4K
  • 08 Dec 2023
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. 
  • 1.4K
  • 27 May 2021
Topic Review
Chromatography in Ukraine
The development of chromatographic science in Ukraine is due to the widespread use of chromatography to solve practical problems. The centers of chromatographic research in Ukraine are in large cities: Kyiv, Kharkiv, Lviv, Odessa, and others. Along with the development of chromatographic research methods, analysis methods for control of food and agricultural raw materials, medicinal products, petroleum products, and determination of the environmental pollution state are created. Chromatography is used in medicine, pharmacology, biology, and other sciences.
  • 1.4K
  • 14 Jun 2022
Topic Review
Glass Fiber Coated Sol–Gel Poly-Diphenylsiloxane
A novel simple and sensitive, time-based flow injection solid phase extraction system was developed for the automated determination of metals at low concentration. The potential of the proposed scheme, coupled with flame atomic absorption spectrometry (FAAS), was demonstrated for trace lead and chromium(VI) determination in environmental water samples. The new sorptive extraction system, consisted of an online microcolumn packed with glass fiber coated with sol–gel poly (diphenylsiloxane) (sol–gel PDPS), which is presented here for the first time.
  • 1.4K
  • 13 Jan 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.
  • 1.4K
  • 21 Jun 2023
Topic Review
Contaminant Cocktails of High Concern in Honey
Environmental pollution is a crucial problem in our society, having a better understanding of its consequences, which include the increase of contaminant cocktails present in the environment. The contamination of honeybees can occur through their interaction with the nearby environment. Therefore, if honeybees are previously contaminated, there is a possibility of contamination of their products, such as honey as natural, or minimally processed, product, resulting from the honeybees’ activity.
  • 1.4K
  • 14 Apr 2023
Topic Review
Trending Methods for Rapid Cannabinoids Detection
Roadside testing of illicit drugs such as tetrahydrocannabinol (THC) requires simple, rapid, and cost-effective methods. The need for non-invasive detection tools has led to the development of selective and sensitive platforms, able to detect phyto- and synthetic cannabinoids by means of their main metabolites in breath, saliva, and urine samples. One may estimate the time passed from drug exposure and the frequency of use by corroborating the detection results with pharmacokinetic data. Modified surfaces can also act as filters that allow only the target analyte to participate in the electrode reaction. In the case of cannabinoids, as in the case of other drugs, the investigation of the mechanism of action within the organism is the basis of biosensor development.
  • 1.4K
  • 18 Nov 2022
Topic Review
Chemical Derivatization in Flow Analysis
Chemical derivatization involves modification of the analyte for improving selectivity and/or sensitivity. It is particularly attractive in flow analysis in view of its highly reproducible reagent addition(s) and controlled timing. Then, measurements without attaining the steady state, kinetic discrimination, exploitation of unstable reagents and/or products, as well as strategies compliant with Green Analytical Chemistry, have been efficiently exploited. Flow-based chemical derivatization has been accomplished by different approaches, involving e.g. flow and manifold programming, solid-phase reagents, and strategies for sample insertion and reagent addition, as well as to increase sample residence time.
  • 1.4K
  • 08 Mar 2022
Topic Review
Liquid Chromatography Separation Mechanism
Separation is a critical process to isolate a particular compound, whether it is a natural product or a synthetic product. Studies of a compound’s characteristics and elucidation structure provides reliable results for pure compounds because there is no interference from other compounds. The primary source of difficulty in a separation process is the high similarity between two or more compounds, such as racemic and homologous mixtures. Liquid chromatography has proven to be an effective solution to those problems. The key to liquid chromatography separation is a sustainable retention and elution process. Stationary phases are essential for separating compounds in liquid chromatography. Various liquid chromatography columns of both preparative and quantitative types have been used and continue to develop. This research will discuss the separation mechanism in liquid chromatography.
  • 1.4K
  • 02 Mar 2022
Topic Review
Electrochemical Biosensing of Dopamine Neurotransmitter
Neurotransmitters are biochemical molecules that transmit a signal from a neuron across the synapse to a target cell, thus being essential to the function of the central and peripheral nervous system. Dopamine is one of the most important catecholamine neurotransmitters since it is involved in many functions of the human central nervous system, including motor control, reward, or reinforcement. It is of utmost importance to quantify the amount of dopamine since abnormal levels can cause a variety of medical and behavioral problems. 
  • 1.4K
  • 17 Jun 2021
Topic Review Peer Reviewed
Catalytic Membrane Ozonation
Catalytic membrane ozonation is a hybrid process that combines membrane filtration and catalytic ozonation. The membrane deposited with an appropriate solid material acts as catalyst. As a consequence, the catalytic membrane contactor can act simultaneously as contactor (i.e., improving the transfer/dissolution of gaseous ozone into the liquid phase), as well as reactor (i.e., oxidizing the organic compounds). It can be used in water and wastewater treatment limiting the disadvantages of membrane filtration (i.e., lower removal rates of emerging contaminants or fouling occurrence) and ozonation (i.e., selective oxidation, low mineralization rates, or bromate (BrO3−) formation). The catalytic membrane ozonation process can enhance the removal of micropollutants and bacteria, inhibit or decrease the BrO3− formation and additionally, restrict the membrane fouling (i.e., the major/common problem of membranes’ use). Nevertheless, the higher operational cost is the main drawback of these processes. 
  • 1.4K
  • 13 Apr 2022
Topic Review
Aurones
Aurones are part of the wide family of polyphenols. More specifically, they may be acknowledged as the lower structural counterparts of the best-known flavones, a subclass of flavonoids.
  • 1.4K
  • 27 Jan 2022
Topic Review
Amorphized Cellulose
Amorphized cellulose is partially or completely decrystallized cellulose. Natural celluloses isolated from terrestrial plants (e.g. cotton, wood, etc.), algae (e.g. Cladophora sp., Valonia ventricosa, etc.), shells of some marine tunicates (e.g. Ascidia sp., Halocynthia roretzi, etc.), and synthesized by some bacteria (e.g. Glucon­aceto­bacter sp., Medusomyces gisevii, etc.) along with microcrystalline cellulose, are semicrystalline biopolymers with a crystallinity degree of 50 to 80%.
  • 1.4K
  • 23 Dec 2021
Topic Review
Origanum majorana Essential Oil—Chemistry and Pesticide Activity
Origanum majorana is a medicinal and aromatic plant that belongs to the Lamiaceae family. It is cultivated in several parts of the world and, due to its splendid aroma and taste, is widely used for culinary purposes and in perfumes. The essential oil of the plant, to which is attributed its aroma, contains many secondary metabolites with valuable biological activity. One of them is the pesticide activity, which has attracted much interest. Given the necessity of replacing synthetic pesticides, essential oils are studied in an attempt to find naturally derived products.
  • 1.3K
  • 09 Dec 2022
Topic Review
Green Extraction Techniques Applications in Different Fields
Green extraction techniques (GreETs) emerged in the last decade as greener and sustainable alternatives to classical sample preparation procedures aiming to improve the selectivity and sensitivity of analytical methods, simultaneously reducing the deleterious side effects of classical extraction techniques (CETs) for both the operator and the environment. The implementation of improved processes that overcome the main constraints of classical methods in terms of efficiency and ability to minimize or eliminate the use and generation of harmful substances will promote more efficient use of energy and resources in close association with the principles supporting the concept of green chemistry.
  • 1.3K
  • 10 May 2022
Topic Review
Effervescence-Assisted Microextraction
Effervescence-assisted microextraction emerged in 2011 as a new alternative in this context. The technique uses in situ-generated carbon dioxide as the disperser, and it has been successfully applied in the solid-phase and liquid-phase microextraction fields. This minireview explains the main fundamentals of the technique, its potential and the main developments reported.
  • 1.3K
  • 14 Jan 2021
Topic Review
Separation and Recycling Potential of Rare Earth Elements
Rare earth elements (REEs) are key chemical raw materials in the development of low-carbon industrial processes and especially in green energy technologies. The REEs include 17 elements that can be found in nature (15 lanthanides La-Lu, Sc, and Y). They are ironically quite well represented in the Earth’s crust, except for the radioactive promethium, which is very rare. However, they are rarely found alone and at economically attractive concentrations, which make them expensive and complicated to extract and separate in high purity with conventional separation techniques. 
  • 1.3K
  • 10 Mar 2022
Topic Review
Aragonite and Unusual Pigments Identification
Aragonite is a mineralogical form of calcium carbonate, mainly of biogenic origin. Historical sources report its use in Roman times as an aggregate in mortars, and in the literature it has only been shown in Roman wall paintings. Thus, its use in 16thcentury wall paintings of the church of Santo Stefano in Selva (Cerignale, Apennines of central Italy) is surprising.
  • 1.3K
  • 01 Nov 2021
Topic Review
Synthetic Hemorphin Analogs Containing Non-Natural Amino Acids
The endogenous hemorphins are bioactive peptides with activity on opioid receptors. Several research teams have synthesized, characterized, and pharmacologically evaluated synthetic hemorphin analogs containing unusual amino acids, D-amino acids, α-aminophosphonic acids, and their derivatives. Research focuses on the structure-activity relationship analysis, details on specific methods for their characterization, and the advantage of synthetic hemorphin analogs compared to endogenous peptides as potent biologically active compounds with a complex mechanism of action.
  • 1.3K
  • 05 Dec 2022
Topic Review
Catalytic Adsorptive Stripping Voltammetric Determination of Germanium
In organic free aqueous solutions, germanium is present in the form of Ge(OH)4 tetrahydroxide (pH < 7) or as H3GeO4−, which dominates in alkaline media (pH > 9). In the presence of many ligands containing carboxylic, di-orthophenolic, and polyalcoholic functional groups, Ge(IV) forms stable five-membered ring chelate complexes displaying coordination number 6.
  • 1.3K
  • 17 Feb 2022
  • Page
  • of
  • 16
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of COVID-19
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Academic Video Service
Feedback