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Journal: Critical reviews in analytical chemistry / CRC

25

We have suggested a novel approach for classification of flow methods according to the conditions under which the mass transfer processes and chemical reactions take place in the flow mode: dispersion-convection flow methods (1) and forced-convection flow methods (2). The first group includes continuous flow analysis, flow injection analysis, all injection analysis, sequential injection analysis, sequential injection chromatography, cross injection analysis, multicommutated flow analysis, multisyringe flow injection analysis, multi-pumping flow systems, loop flow analysis and simultaneous injection effective mixing flow analysis. The second group includes segmented flow analysis, zone fluidics, flow batch analysis, sequential injection analysis with a mixing chamber, stepwise injection analysis and multicommutated stepwise injection analysis. The offered classification allows to systematize a large number of the flow methods. Recent development and application of dispersion-convection flow methods and forced-convection flow methods are presented. [Figure: see text].

Concepts: Series, Chemical reaction, Chemical substance, According to Jim, Chemical engineering, Limit of a sequence, Mass transfer, AutoAnalyzer

25

Fusidic acid, an antibiotic produced from the Fusidium coccineum fungus, belongs to the class of steroids, but has no corticosteroid effects. It is indicated for the treatment of infections caused by methicillin-resistant Staphylococcus aureus strains. The aim of this study was to search for the properties of fusidic acid published so far in the literature, as well as the methods developed for its determination in biological samples and pharmaceutical formulations. From the findings, we can conclude that fusidic acid has been used for decades and is indicated for the treatment of serious infections caused by Gram-positive microorganisms to this day. Furthermore, it is a hypoallergenic agent, has low toxicity, shows low resistance, and has no cross-resistance with other clinically used antibiotics. The analytical method of high-performance liquid chromatography has been widely used, since it can reduce the cost and time of analysis, making it more viable for routine quality control in the pharmaceutical industry.

Concepts: Medicine, Bacteria, Staphylococcus aureus, Antibiotic resistance, Chromatography, High performance liquid chromatography, Antibiotic, Penicillin

25

Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano-sized, high surface area, thermally and chemically stable, and provide excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions and H-bonding) for organic compounds and covalent interactions for metal ions. These properties lead to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous publications on graphene applications are available in recent times, but few review papers focused on its applications in analytical chemistry. This article focuses on recent pre-concentration of trace elements, organic compounds and biological species using SPE-based graphene, graphene oxide and their modified forms. Solid phase microextraction and micro SPE (µSPE) methods based on graphene are discussed.

Concepts: Condensed matter physics, Chemistry, Atom, Chemical element, Analytical chemistry, Organic chemistry, Materials science, Chemical engineering

0

Antibiotics have unquestionable importance in the treatment of many infections. Oxytetracycline is an antibiotic belonging to the class of tetracyclines, available for use in human and veterinary medicine. Development of analytical methods that prove the quality and efficacy of these drugs is fundamentally important to the pharmaceutical industry. In this context, the research presents an overview of the analytical profile of oxytetracycline, describing its chemical and pharmacological properties, and analytical methods for quantification of this drug in biological samples and pharmaceutical products. Oxytetracycline can be analyzed in these matrices by many types of methodologies. However, High Performance Liquid Chromatography is the most widely used, being recommended by official compendia. This kind of study can be useful to support the development of new efficient and sustainable analytical methods that may be utilized in the quality control routine of oxytetracycline in pharmaceutical products and pharmacokinetic monitoring in biological samples.

Concepts: Pharmacology, Medicine, Drug, Greek loanwords, High performance liquid chromatography, Analytical chemistry, Pharmaceutical drug, Pharmacy

0

There is a significant demand for devices that can rapidly detect chemical-biological-explosive (CBE) threats on-site and allow for immediate responders to mitigate spread, risk, and loss. The key to an effective reconnaissance mission is a unified detection technology that analyzes potential threats in real time. In addition to reviewing the current state of the art in the field, this review illustrates the practicality of colorimetric arrays composed of sensors that change colors in the presence of analytes. The review also describes an outlook towards future technologies, and describes how they could possibly be used in areas such as war zones to detect and identify hazardous substances.

Concepts: The Key, Real number, The Current, Technology, Identification, Sensor, Nuclear weapon, CBC Radio One

0

Supercritical fluid extraction (SFE), as a new green extraction technology, has been used in extracting various metal species. The solubilities of chelating agents and corresponding metal chelates are the key factors which influence the efficiency of SFE. Other main properties of them such as stability and selectivity are also reviewed. The extraction mechanisms of mainly used chelating agents are explained by typical examples in this paper. This is the important aspect of SFE of metal ions. Moreover, the extraction efficiencies of metal species also depends on other factors such as temperature, pressure, extraction time and matrix effect. The two main complexation methods namely in-situ and on-line chelating SFE are described in detail. As an efficient chelating agent, tributyl phosphate-nitric acid (TBP-HNO3) complex attracts much attention. The SFE of metal ions, lanthanides and actinides as well as organometallic compounds are also summarized. With the proper selection of ligands, high efficient extraction of metal species can be obtained. As an efficient sample analysis method, supercritical fluid chromatography (SFC) is introduced in this paper. Recently, the extraction method combining ionic liquids (ILs) with supercritical fluid has been becoming a novel technology for treating metal ions. The kinetics related to SFE of metal species is discussed with some specific examples.

Concepts: Ligand, Citric acid, Chelation, Chelating agents, Supercritical fluid, Ethylenediamine, Gadolinium

0

Naphthalene sulfonates are highly water-soluble compounds, indicating a high mobility in aquatic systems along with high temperature stability which are important substances in the chemical industry. This review covers analytical methods, instruments and techniques used for the pre-concentration and analysis of naphthalene sulfonates in different matrices. All analytical steps including the extraction from real samples, their detection by spectrophotometric and chromatographic techniques, as well as methods of identification of this class of compounds are described in detail. The methods normally employed for the extraction and pre-concentration of these compounds is solid-phase extraction (including molecularly imprinted polymers and anion-exchange), while their quantification are performed using high-performance liquid chromatography, capillary electrophoresis, gas chromatography- mass spectrometry, liquid chromatography-mass spectrometry, and spectrophotometric techniques. In this review, in addition to chromatographic and spectrophotometric methods, electrochemical innovations appearing in the literature will be also explored.

Concepts: Protein, Chromatography, High performance liquid chromatography, Analytical chemistry, Gas chromatography, Liquid chromatography-mass spectrometry, Thin layer chromatography

0

Cyanotoxins are toxic and are found in eutrophic, municipal and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple and accurate analytical methods for the identification and determination of cyanotoxins are required. In this article, the sampling methodologies and applications of solid phase based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase microextraction (SPME), solid phase extraction (SPE) and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

Concepts: Water, Condensed matter physics, Ice, Analytical chemistry, Phase, Solid phase microextraction, Phases of matter, Water supply network

0

Infections are the second leading cause of mortality worldwide and there are many reasons justifying the need for further studies of antimicrobial agents. The cefadroxil is a drug that has bactericidal activity and broad spectrum of action. Quantitative analyzes about cefadroxil are essential for the understanding of bioavailability, bioequivalence and therapeutic control, which will ensure the product characteristics and patient safety. Thus, this study highlights a brief literature review about drug and existing methods developed for the determination of cefadroxil found in official and scientific papers. According literature to the found methods, liquid chromatography and spectrophotometry of absorption in the ultraviolet region prevailed over the others. Importantly, most of the solvents used for the development of the described analytical methods, are toxic to the environment, making it necessary, educate researchers and pharmaceutical companies insert nontoxic solvents to provide environmentally friendly methods and better benefits to equipment and mainly to analysts.

Concepts: Scientific method, Pharmacology, Environment, Natural environment, Academic publishing, Research, Analytical chemistry, Pharmacokinetics

0

For many years there has been growing demand for gaseous reference materials, which is connected with development in many fields of science and technology. As a result, new methodological and instrumental solutions appear that can be used for this purpose. Appropriate quality assurance/quality control (QA/QC) must be used to make sure that measurement data are a reliable source of information. Reference materials are a significant element of such systems. In the case of gas samples, such materials are generally called reference gas mixtures. This article presents the application and classification of reference gas mixtures, which are a specific type of reference materials, and the methods for obtaining them are described. Construction solutions of devices for the production of reference gas mixtures are detailed, and a description of a prototype device for dynamic production of reference gas mixtures containing aroma compounds is presented.

Concepts: Science, Chemical substance, Liquid, Olfaction, Chemical compound, Gas, Technology, Specific heat capacity