Dave Eggers’s You Shall Know Our Velocity (2002) can be read as a (post) modern voice in the ongoing debate on educational, transformative and redemptive po- tential of foreign travel for the young ...Americans in the late 1990s. The article focuses on representation of global travel experience in the novel employing American Old World journey conventions on the one hand and tourism-travel dichotomy on the other. The backpackers in Eggers’s novel can be characterized as drifters. Their encounters with otherness most often result in confusion. All in all, the novel downplays the role of travel in the globalized, homogenized world at the turn of the 21st century.
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•The classification of certified reference materials (CRMs) in the field of food matrix is presented.•CRMs that are certified for total selenium and seleno species are ...discussed.•Importance of CRMs for QA/QC and CRMs development for determining Se in food is presented.•The need for certified CRMs for organic forms of Se in the food matrix.
Micronutrients are one of the most important groups of nutrients that our body needs daily in trace amounts to tackle deficiencies. Selenium (Se) is a mineral that occurs naturally in foods and is an essential component of selenoproteins that support the healthy functioning of the human body. Therefore, monitoring dietary Se concentrations must be a higher priority to meet daily intakes. Fulfillment can be addressed through applying various analytical techniques, and the certified reference materials (CRMs) tool plays a crucial role in quality assurance/quality control (QA/QC). The availability of certified CRMs for total Se content with addition to their species is presented. The review emphasizes the necessity of incorporating more food matrix CRMs certifying Se species, apart from total Se content, to meet method validation requirements for food analysis laboratories. This would help CRM producers bridge the gap between available food matrix materials that are not certified for Se species.
Liquid–phase microextraction: A review of reviews Rutkowska, Małgorzata; Płotka-Wasylka, Justyna; Sajid, Muhammad ...
Microchemical journal,
September 2019, 2019-09-00, Letnik:
149
Journal Article
Recenzirano
Sample preparation is an important step in chemical analysis. It is generally done to deal with problems associated with the nature of the matrix, low analyte concentrations in real samples or ...analyte features incompatible with the instrumentation. Classical methods of extraction consume large volumes of hazardous solvents and other reagents and are not in line with the recent emergence of green analytical chemistry. Liquid-phase microextraction is a miniaturized version of classical liquid–liquid extraction and is characterized by the minimum consumption of solvents. Over time, liquid-phase microextraction has gone through many developments, from basic procedures to more advanced modifications. These have consistently been the subject of many review articles. In this article, we attempt to summarize the review articles published on different versions of LPME and its different aspects and areas of application. Special focus has been given to DLLME, which is the most widely used form of LPME.
•Scientific information on the LPME techniques is presented.•Review articles published on different versions of LPME are summarized.•Review articles published on different aspects of LPME and areas of its application is discussed.•The classification of LPME techniques is presented.
Over the last two decades the process of development and application of a new types of molecular imprinted polymer (MIP) sorbents in the field of analytical chemistry have been widely described in ...the literature. One of the new trends in analytical chemistry practice is the use of new types of MIP sorbents as specific sorption materials constituting the stationary phase in advanced separation techniques. The following review paper contains comprehensive information about the application of a specific and well defined MIP sorbents (with the data base in the paper about the reagents used in MIP preparation process) as stationary phases in separation techniques including high performance liquid chromatography and capillary electrochromatography. Coverage includes newly created types of stationary phases (MIP sorbents) used for chiral recognition, with the focus on applications in enantioselective separation.
•The current role of MIP-type affinity materials in chiral recognition is provided.•The application of MIPs in the field of assessing the optical purity of chemical compounds is presented.•Types of MIPs used as stationary phases in separation techniques are mentioned.•Application of MIPs in enantioseparation by chromatographic techniques is discussed.•Future challenges concerning MIPs are discussed.
Extraction with environmentally friendly solvents Płotka-Wasylka, Justyna; Rutkowska, Małgorzata; Owczarek, Katarzyna ...
TrAC, Trends in analytical chemistry (Regular ed.),
June 2017, 2017-06-00, Letnik:
91
Journal Article
Recenzirano
The ever-increasing demand for determining compounds at low concentration levels in complex matrices requires a preliminary step of analytes isolation/enrichment in order to employ a detection ...technique characterized by high sensitivity at low LOQ. Sample preparation is considered as crucial part of analytical procedures. Previously the parameter of “greenness” is as important as selectivity in order to avoid using harmful organic solvents in sustainable extraction techniques. These solvents can generate hazardous, toxic waste while consuming large resources volume. Developing new green solvents is one of the key subjects in Green Chemistry in order to reduce the intensity of anthropogenic activities related to analytical laboratories. A lot of new, more eco-friendly media have been employed as extractant phases. These media, besides of being more eco-friendly, provide shorter extraction times, simplicity, low cost, better selectivity in some cases. The most promising, most widely used green extraction solvents are described in this review.
•Replacement of VOCs by eco-friendly solvents is becoming increasingly important.•Several new solvents have been developed and introduced in analytical practice.•Solvents environmental impact assessment is becoming increasingly important.•Analytical chemistry requires solvents “greenness” assessment systems to be comprehensive.
This overview discusses the ideas behind a collection of articles by invited authors on a diverse range of complex chemical mixtures and analytical methods which represent some of the most relevant ...and interesting issues on emerging contaminants of environmental health concerns. These chemicals, including those in high volume production, are released on an ongoing basis as a result of various human activities. Moreover, these emerging contaminants are highly toxic to humans and ubiquitous in the environment. The terms “environmental pollution" and “food web contaminant" became widely known from the first decades of the XX century and as a historical background, they have an early link to the agricultural use of mercury fungicides and DDT. Surprisingly for chemists and society, the 1960s saw the emergence of the global problem of environmental and food contamination with polychlorinated biphenyls (PCBs). The environmental science paradigm has lost none of its importance in the meantime, although it has evolved to encompass a vast number of environmentally hazardous chemicals, many of which are termed as “emerging". To put it simply, air-water-soil/sediment are the first compartments affected and become reservoirs or sinks for environmental pollutants, the next is the food web, topped by the top animal predators and humans. Understanding the occurrence, environmental fate and biotoxicity of emerging contaminants is of interest to many areas of science.
Mesoporous/hierarchical zeolites (HZs) are a relatively new group of materials, and interest in their application in catalysis is continuously growing. This paper presents recent achievements in the ...application of mesoporous zeolites in catalytic reactions of nitrogen pollutant conversion. The analysis presented includes processes such as selective catalytic reduction of NOx with ammonia (NH3-SCR, DeNOx), selective catalytic oxidation of ammonia (NH3-SCO, AMOx), and catalytic decomposition of N2O. Different zeolite topologies and methods of their modification focused on mesoporosity generation (e.g., desilication, dealumination, steaming, self-assembly techniques, and application of hard and soft templates) are reviewed and compared with respect to catalytic processes. Special attention is paid to the role of porous structure and acidity, as well as the form of deposited transition metals, in the catalytic activation of modified zeolites in the elimination of nitrogen pollutants from flue gases.
The use of the ‘omics techniques in environmental research has become common-place. The most widely implemented of these include metabolomics, proteomics, genomics, and transcriptomics. In recent ...years, a similar approach has also been taken with the analysis of volatiles from biological samples, giving rise to the so-called ‘volatilomics’ in plant analysis. Developments in direct infusion mass spectrometry (DI-MS) techniques have made it possible to monitor the changes in the composition of volatile flux from parts of plants, single specimens, and entire ecosystems in real-time. The application of these techniques enables a unique insight into the dynamic metabolic processes that occur in plants. Here, we provide an overview of the use of DI-MS in real-time volatilomics research involving plants.
Direct infusion mass spectrometry (DI-MS) techniques are a valuable tool for real-time monitoring of the plant volatilome.DI-MS techniques are particularly useful in detecting brief episodes of increased biogenic volatile organic compound emissions caused, for instance, by herbivore attacks.Current studies on the use of DI-MS techniques for the determination of plant volatiles are conducted at several scales, from parts of plants and whole specimens to entire ecosystems.Proton transfer reaction MS is the preeminent technique used for the monitoring of volatile plant metabolites.Current developments in DI-MS solutions are focused on the application of tandem MS.
The primary objective of this review article is to strategically screen and highlight the advancements in the area of solid phase microextraction (SPME). The plenty of review articles have been ...written on different aspects of SPME, this review is dedicated to provide the brief but clear overview of the research footprints so produced from SPME. Some of the key advancements in types and designs, coating materials, coating strategies, in vivo sampling and direct coupling of SPME with MS have been critically discussed.
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