Modern Separation Techniques Research Articles

Investigating the potential of electrostatic charging to separate cementitious binder and sand

The environmental footprint of concrete is largely influenced by the binder. It is therefore of high interest to investigate the potential reuse of the binder retrieved by modern separation techniques. However, studies found that the recycled cement fraction (RCF) still contained a certain amount of siliceous concrete aggregates, which forms an obstacle in the upcycling of RCF. In this study, the potential of electrostatic separation as a method to separate cementitious binder (hydrated and unhydrated) and sand (silica) is evaluated. Different cementitious powders and silica (sand) were prepared, resulting in a total of 9 powders and 8 mixtures. The mixtures consisted of a combination of silica and one of the cementitious powders (50/50 wt%) with a particle size of the components <125 μm. The potential of the studied technique was evaluated through charging measurements and x-ray fluorescence (XRF). Silica was assumed to contain no CaO and the detected CaO was therefore assigned to the cementitious powders. Results showed that silica and silica-rich fly ash (FA) particles became negatively charged, blast furnace slag (BFS) particles remained largely charge neutral and all other cementitious particles obtained a positive charge. Through electrostatic separation an enrichment of the cementitious binder fraction for all mixtures was obtained at the negative electrode. FA-Silica achieved the highest enrichment (89.9%), CEM III/B-Silica the lowest (4.7%) and the hydrates were enriched ranging from 28.0 to 31.8%.

Advancing Ion Separation: Covalent-Organic-Framework Membranes for Sustainable Energy and Water Applications.

ConspectusMembranes are pivotal in a myriad of energy production processes and modern separation techniques. They are essential in devices for energy generation, facilities for extracting energy elements, and plants for wastewater treatment, each of which hinges on effective ion separation. While biological ion channels show exceptional permeability and selectivity, designing synthetic membranes with defined pore architecture and chemistry on the (sub)nanometer scale has been challenging. Consequently, a typical trade-off emerges: highly permeable membranes often sacrifice selectivity and vice versa. To tackle this dilemma, a comprehensive understanding and modeling of synthetic membranes across various scales is imperative. This lays the foundation for establishing design criteria for advanced membrane materials. Key attributes for such materials encompass appropriately sized pores, a narrow pore size distribution, and finely tuned interactions between desired permeants and the membrane. The advent of covalent-organic-framework (COF) membranes offers promising solutions to the challenges faced by conventional membranes in selective ion separation within the water-energy nexus. COFs are molecular Legos, facilitating the precise integration of small organic structs into extended, porous, crystalline architectures through covalent linkage. This unique molecular architecture allows for precise control over pore sizes, shapes, and distributions within the membrane. Additionally, COFs offer the flexibility to modify their pore spaces with distinct functionalities. This adaptability not only enhances their permeability but also facilitates tailored interactions with specific ions. As a result, COF membranes are positioned as prime candidates to achieve both superior permeability and selectivity in ion separation processes.In this Account, we delineate our endeavors aimed at leveraging the distinctive attributes of COFs to augment ion separation processes, tackling fundamental inquiries while identifying avenues for further exploration. Our strategies for fabricating COF membranes with enhanced ion selectivity encompass the following: (1) crafting (sub)nanoscale ion channels to enhance permselectivity, thereby amplifying energy production; (2) implementing a multivariate (MTV) synthesis method to control charge density within nanochannels, optimizing ion transport efficiency; (3) modifying the pore environment within confined mass transfer channels to establish distinct pathways for ion transport. For each strategy, we expound on its chemical foundations and offer illustrative examples that underscore fundamental principles. Our efforts have culminated in the creation of groundbreaking membrane materials that surpass traditional counterparts, propelling advancements in sustainable energy conversion, waste heat utilization, energy element extraction, and pollutant removal. These innovations are poised to redefine energy systems and industrial wastewater management practices. In conclusion, we outline future research directions and highlight key challenges that need addressing to enhance the ion/molecular recognition capabilities and practical applications of COF membranes. Looking forward, we anticipate ongoing advancements in functionalization and fabrication techniques, leading to enhanced selectivity and permeability, ultimately rivaling the capabilities of biological membranes.

A review of bioanalytical applications of microextraction techniques combined with derivatization.

Microextraction techniques have attracted the attention of many researchers working in the field of bioanalysis due to their unique advantages, mainly in downsizing the scale of sample preparation steps. In parallel, analytical derivatization offers a powerful combination in terms of additional sensitivity, selectivityand compatibility with modern separation techniques. The aim of this review is to discuss the most recent advances in bioanalytical sample preparation based on the combination of microextraction and analytical derivatization. Both innovative fundamental reports and analyte-targeted applications are included and discussed. Dispersive liquid-liquid extraction and solid-phase microextraction are the most common techniques that typically combined with derivatization, while the development of novel and greener protocols is receivingsubstantial consideration in the field of analytical chemistry.

Identification of Anti-Inflammatory and Anti-Proliferative Neolignanamides from Warburgia ugandensis Employing Multi-Target Affinity Ultrafiltration and LC-MS.

Previous reports have illustrated that the incidence and mortality of cancer are increasing year by year worldwide. In addition, the occurrence, development, recurrence and metastasis of cancer are closely related to inflammation, which is a kind of defensive response of human body to various stimuli. As an important medicinal plant in Africa, Warburgia ugandensis has been reported to have certain anti-inflammatory and anti-proliferative activities, but its specific components and mechanisms of action remain elusive. To tackle this challenge, affinity ultrafiltration with drug targets of interest coupled to high-performance liquid chromatography-mass spectrometry (AUF-HPLC-MS/MS) could be utilized to quickly screen out bioactive constituents as ligands against target enzymes from complex extracts of this plant. AUF-HPLC-MS/MS with four drug targets, i.e., cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), topoisomerase I (Top I) and topoisomerase II (Top II) were used to rapidly screen and characterize the anti-inflammatory and anti-proliferative natural ligands from W. ugandensis, and the resulting potential active compounds as ligands with specific binding affinity to COX-2, 5-LOX, Top I and Top II, were isolated with modern separation and purification techniques and identified with spectroscopic method like NMR, and then their antiinflammatory and anti-proliferative activities were tested to verify the screening results from AUF-HPLC-MS/MS. Compounds 1 and 2, which screened out and identified from W. ugandensis showed remarkable binding affinity to COX-2, 5-LOX, Top I and Top II with AUF-HPLC-MS/MS. In addition, 1 new compound (compound 3), together with 5 known compounds were also isolated and identified from W. ugandensis. The structure of compound 3 was elucidated by extensive 1D, 2D NMR data and UPLC-QTOF-MS/MS. Furthermore, compounds 1 and 2 were further proved to possess both anti-inflammatory and anti-proliferative activities which are in good agreement with the screening results using AUF-HPLC-MS/MS. This work showcased an efficient method for quickly screening out bioactive components with anti-inflammatory and anti-proliferative activity from complex medicinal plant extracts using AUF-HPLC-MS/MS with target enzymes of interest, and also demonstrated that neolignanamides (compounds 1 and 2) from W. ugandensis would be the active components responsible for its anti-inflammatory and anti-proliferative activity with the potential to treat cancer and inflammation.

Aldehyde oxidase assay by capillary electrophoresis: From off-line, online up to immobilized enzyme reactor.

Capillary electrophoresis is a modern separation technique characterized by many benefits, which qualify it also for enzyme assays and the study of enzyme kinetics during drug development. Homogeneous or heterogeneous approaches can be followed for the enzymatic incubation. In this study, an immobilization procedure of aldehyde oxidase on magnetic particles was developed considering their integration with capillary electrophoresis. A number of magnetic nano/microparticle types were tested for this purpose, showing that aldehyde oxidase was most active when immobilized on bare silica magnetic nanoparticles. Primarily, the reusability of the enzyme immobilized on bare silica nanoparticles was tested. Three consecutive incubations with substrate could be performed, but the activity considerably dropped after the first incubation. One reason could be an enzyme detachment from the nanoparticles, but no release was detected neither at 4°C nor at 37°C during 5 h. The drop in enzymatic activity observed in consecutive incubations, could also be due to inactivation of the enzyme over time at given temperature. For the immobilized enzyme stored at 4°C, the activity decreased to 83% after 5 h, in contrast with a steep decrease at 37°C to 37%.

Response surface methodology for microwave-assisted extraction of pectin from cocoa pod husk (Theobroma cacao) mediated by oxalic acid

Rather than disposed of as waste, cocoa pod husk has a potential to be the source of natural pectin. An efficient extraction process can provide a sufficient amount of pectin. This study aims to analyze the performance of microwave-assisted extraction to separate pectin from cocoa pod husk mediated by cheaper and milder acidifying agent, oxalic acid. Response surface methodology was performed to investigate the effect of pH, ratio of liquid to solid, and irradiation time on the quantity of pectin extracted. Our model showed that reducing ratio of liquid to solid did not dramatically affect extraction yield. Higher oxalic acid concentration, i.e. lower pH, and prolonged irradiation time increased yield, yet decreased degree of esterification which influences the gelling ability of pectin. This technique also significantly shortened the extraction time compared to conventional method. Our finding complements the application of microwave-assisted extraction as a modern separation technique.

Regulation of Herbal Medicine in Hungary

In order to meet the growing needs of the European Union medicinal and aromatic plants, Hungary is still one of the major exporters today, although earlier, until the 1980s, we were considered a great herb-growing nation. Therefore, the development of the national medicinal and aromatic herb growing sector is an essential requirement for maintaining and developing our market position. The natural conditions of Hungary favor the cultivation of medicinal and aromatic plants. There are more than 330 herbs in our country. About seventy percent of the drugs grown and harvested are exported. However, significant changes are needed in domestic sales and further processing in order to become a leading industrial sector. Hungary also possesses modern separation techniques and large instruments for analysis, which allow the proper analytical examination of drugs and the precise determination of their active substances. Our universities and research institutes are also prepared to study the active ingredients of herbs by molecular biological methods, which may allow the exact mechanism of action of bioactive substances to be determined and the herbs to be reassessed. Our accession to the European Union the palette of products made from former herbs has significantly changed. From 2013, the category of medicinal product was discontinued, and the preparations were classified as either food or medicine. However, there are significant costs associated with qualifying as a drug, so drugs or extracts are largely added to dietary supplements. As a result, the strange situation is that dietary supplements are prohibited from making any health claims, even though the dietary supplement is actually not for the benefit of a healthy population, but for those who have a health problem or do not have suitable foods, which are rich in bioactive substances. The justification of phytotherapy must be demonstrated, depending on the state of the art. In the context of safe therapy, studies must follow the requirements of medicines and only then can they become herbal medicines. There is still much to be desired in this area in our country. Classification as a drug is based on expensive animal tests and clinical studies. A new problem arises here, as herbal cure is currently part of the arsenal of complementary medicine. With few exceptions, clinical doctors do not use herbal therapies. Patients usually ask the advice of pharmacists, naturalists, and more rarely, dietitians. At the Arteriosclerosis Research Group, at the II. Department of Medicine and Institute of Pharmacognosy several decades of biomedical research have served and serve the purpose of evaluating and reassessing the effects of plants used in folk medicine. Over the years, we have been searching for drugs, extracts, and medicines of natural origin that are useful in liver and intestinal diseases known in folk medicine, and are believed to have lipid lowering, antioxidant and immune stimulating effects. In the article, animal and human studies will be also presented.

Mathematical model of dry coal deshaling by using FGX vibrating air table

Dry coal separation process is a relatively new method for coal separation in Poland. First air separators which were used on bigger scale was in United States before Second World War in 1930s. Nowadays is widely used in China, United States, Russia and all those places where access to water is limited. Last year’s very popular become separation by using vibrating air tables FGX where beneficiation process use air suspension which separate heavier particles from light coal grains. This separation process depends on different parameters like preparation of feed and it parameters, grain size fraction, air supply etc.. This paper will describe what is it a dry coal separation, modern separation techniques and in the main part focus on creating mathematical model which will present the quality of using this kind of process for coal deshaling. Mathematical model will base on dependence between calorific value and ash content in the tested samples.

Designing heparan sulfate-based biocompatible polymers and their application for intracellular stimuli-sensitive drug delivery

Heparan sulfate (HS) is a kind of natural polysaccharides with good biocompatibility. And as drug carriers, it has some advantages compared to heparin. However, the preparation of HS is cumbersome and difficult, which limits its application in drug delivery. Here, we use modern separation technique combined with chromatography to establish a new preparation method of HS. The molecular weight and degree of dispersion of HS were (1.03 × 104 ± 107) kDa and 1.106, respectively. HS also showed low anticoagulation activity in comparison with heparin. Subsequently, novel redox-sensitive heparan sulfate-cystamine-vitamin E succinate (HS-SS-VES, HSV) micelles were designed to increase tumor selectivity and improve the therapeutic effect of doxorubicin (DOX). DOX-loaded HSV micelles (DOX/HSV) with spherical morphology had average particle size of 90–120 nm and good redox-triggered release behavior. The cell viabilities of blank micelles were >90% in both human breast cancer (MCF7) cells and African green monkey SV40-transformed kidney fibroblast (COS7) cells. However, the cytotoxicity of DOX/HSV in MCF7 cells was higher than that of COS7 cells. Flow cytometry analyses and confocal laser scanning microscopy observation indicated that DOX/HSV micelles were internalized by endocytosis, and then the drug was released quickly and entered the nuclei of tumor cells. The results demonstrate that high-purity HS can be prepared and has the potential to be further used for drug delivery in antitumor applications.

Modern separation techniques coupled to high performance mass spectrometry for glycolipid analysis.

Glycolipids (GLs), involved in biological processes and pathologies, such as viral, neurodegenerative and oncogenic transformations are in the focus of research related to method development for structural analysis. This review highlights modern separation techniques coupled to mass spectrometry (MS) for the investigation of GLs from various biological matrices. First section is dedicated to methods, which, although provide the separation in a non-liquid phase, are able to supply important data on the composition of complex mixtures. While classical thin layer chromatography (TLC) is useful for MS analyses of the fractionated samples, ultramodern ion mobility (IMS) characterized by high reproducibility facilitates to discover minor species and to apply low sample amounts, in addition to providing conformational separation with isomer discrimination. Second section highlights the advantages, applications and limitations of liquid-based separation techniques such as high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) in direct or indirect coupling to MS for glycolipidomics surveys. The on- and off-line capillary electrophoresis (CE) MS, offering a remarkable separation efficiency of GLs is also presented and critically assessed from the technical and application perspective in the final part of the review.

ChemInform Abstract: Application of Resorcinarene Derivatives in Chemical Separations

AbstractReview: 62 refs.

Efficacy-Driven Quality Control Platform for Chinese Herbal Medicine

The quality control of CHM is always a key issue for the clinical usage, and also is a secure for high quality of clinical trials, especially in the consistency and controllability (5,6). Great progress has been made in the quality control of CHM due to modern separation and characterization techniques. Briefly, it can be divided into three stages. The first stage was the usage of identification of CHM based on material medical's morphology, one or two markers' thin-layer chromatography (TLC) (7). The morphological identification was described in the 1953 and 1963 editions of the Chinese Pharmacopeia. Since 1985, TLC has been employed for the qualitative evaluation of CHM (8). Morphological identification can give a quick identification of CHM; and TLC method has the advantages of operating conveniently, quick identification and preliminary quantification of marker compounds. However, morphological identification cannot explore the substantial basis of CHM; while TLC also has the weaknesses of limitation in multiple compounds detection, low selectivity in quantification. CHM is a multicomponent combination, so just use TLC method for several marker compounds' quality control cannot reflect the real quality of CHM. Nevertheless, the chosen of marker compounds are mostly based on main compounds in CHM, which may have no relevance with pharmacological activity. Based on these weaknesses, Researchers started to focus on multiple active compounds analysis method. So the second stage was the application of comprehensive methods which reflect the characteristics of multiple targets and synergistic action of CHM using fingerprint (including chromatographic and spectroscopic ones, contain TLC, HPLC, GC, CE, IR, NIR, NMR, DNA, GC-MS, LC-MS, LC-DAD- MSn, and LC-DAD-NMR) (9,10). It presents the entire composition information and fulfills the TCM characteristics. Therefore, fingerprint analysis has been internationally accepted for the quality control of herbal medicines (8). To combine chemical character with bioactivity, bio-fingerprint and metabolic fingerprint have also been used for directly selecting the marker constituents for quality control (11). However, these marker components were selected by preliminary comparison of fingerprints, more work need to be done for the activity confirmation.

Use, analysis, and regulation of pesticides in natural extracts, essential oils, concretes, and absolutes

Natural extracts used by the fragrance and cosmetics industries, namely essential oils, concretes, resinoids, and absolutes, are produced from natural raw materials. These are often cultivated by use of monoculture techniques that involve the use of different classes of xenobiotica, including pesticides. Because of these pesticides’ potential effect on public health and the environment, laws regarding permitted residual levels of pesticides used in cultivation of raw materials for fragrance and cosmetic products are expected to become stricter. The purpose of this review is to present and classify pesticides commonly used in the cultivation of these natural raw materials. We will summarize the most recent regulations, and discuss publications on detection of pesticides via chemical analysis of raw natural extracts. Advances in analytical chemistry for identification and quantification of pesticides will be presented, including both sample preparation and modern separation and detection techniques, and examples of the identification and quantification of individual pesticides present in natural extracts, for example essential oils, will be provided.

Application of resorcinarene derivatives in chemical separations

The applications of resorcinarene derivatives in modern separation techniques including high performance liquid chromatography (HPLC), gas chromatography (GC), capillary electrophoresis (CE), ion chromatrography (IC), and liquid membranes are reviewed in this paper. Resorcinarenes are macrocyclic compounds which can be modified with various substituents on upper and lower rims to provide specific functionality and selectivity. The derivatives can be adsorbed or covalently bound to the stationary phase of HPLC, GC, and IC, or used as pseudo-stationary phase in CE to separate organic or inorganic species. They have been tested as carriers to selectively transfer species from source phase to receiving phase in bulk liquid membranes, supported liquid membranes, and polymer inclusion membranes. These broad applications of resorcinarene-based macrocyclic ligands indicate that they are a promising class of compounds that are worthwhile to be explored in both synthesis and separation applications.

Elucidation of Diels-Alder Reaction Network of 2,5-Dimethylfuran and Ethylene on HY Zeolite Catalyst.

The reaction of 2,5-dimethylfuran and ethylene to produce p-xylene represents a potentially important route for the conversion of biomass to high-value organic chemicals. Current preparation methods suffer from low selectivity and produce a number of byproducts. Using modern separation and analytical techniques, the structure of many of the byproducts produced in this reaction when HY zeolite is employed as a catalyst has been identified. From these data, a detailed reaction network is proposed demonstrating that hydrolysis and electrophilic alkylation reactions compete with the desired Diels-Alder/dehydration sequence. This information will allow the rational identification of more selective catalysts and more selective reaction conditions.

Plasma Steroid Level Measured Using Modern Separation Techniques as Biomarkers in Biological Diagnostics

Plasma Steroid Level Measured Using Modern Separation Techniques as Biomarkers in Biological Diagnostics

Urinary Steroids Measured by Modern Separation Techniques and Applied as Biomarkers in Stress Studies

A biomarker is a measure of the interaction occurring in the biological systems between the organism and the potential risks that may be of chemical, physical, or biological character. The measured response of the body caused by this interaction can be of physiological, functional or biochemical character and can be captured at the cellular or molecular level. Steroids, especially cortisol and cortisone, are valuable biomarkers serving primarily the assessment of the organisms reaction to exposure to chronic stress. The problem of stress and its impact on the development of endocrinological, metabolic, psychiatric and cardiovascular diseases has been the subject of intense research for some years. Studies on cortisol and cortisone in biological materials such as serum, plasma, urine, or saliva were applied to measure stress levels in the body. The advantage of urine-based measurements lies in non-invasive nature of the method of sampling. The serum cortisol and cortisone levels may be increased in certain disease states such as diabetes, obesity, hyperthyroidism, and in pregnancy. Therefore, measurement of free cortisol in urine is the most reliable way to diagnose either stress disorder, or the functioning of the hypothalamic-pituitary-adrenal (HPA) axis. In the review, several validated high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary chromatography (MECC) assays for determination of steroids in urine samples were compared. Because these methods are automated, simple, rapid, and sensitive, they can be applied easily to the analysis of urine samples. However, HPLC is sometimes limited in its separation efficiency, and the consumption of organic solvents is relatively high. On the other hand, the important drawback of MECC is that sometimes it cannot be sensitive enough to determine low concentrations, e.g., when the sample injection volume is low and the optical path-length short. Nevertheless, it finally seems that MECC offers greater separation efficiency than HPLC and significantly reduces the analysis time and the operating costs compared to HPLC. In summary, those methods carry a great analytical potential, especially because urine, used as biological matrix and treated as a biological fluid, is easy to obtain in non-invasive collection procedures. Keywords: Urine, Biomarkers, Steroid hormones, Stress studies, High-performance liquid chromatography (HPLC), Micellar electrokinetic capillary chromatography (MEKC)

Cover Picture: Electrophoresis 18'2008

AbstractIssue number 18 is a Special Issue on “CE and CEC Innovations” consisting of 26 papers arranged into six sections. This Issue has one review article on the application of modern separation techniques in metabonomics, while the remaining articles pertain to microfluidics and miniaturization, novel trends in fundamentals and methodologies, various aspects of capillary coatings, open tubular CEC, MIP‐CE, polar and nonpolar monoliths, MEEKC, MEKC and enantioseparations by CE and CEC.In addition Issue 18 has a “Fast Track” article on the CE‐based assay of sirtuin enzymes.

Some pharmacological studies with Cycleanine, a diphenylbisbenzylisoquinoline alkaloid from Stephania hernandifolia

Stephania hernandifolia belonging to the family Menispermaceae is the biggest storehouse of diphenylbisbenzylisoquinoline (DBBI) alkaloids. Exhaustive chemical processing of the bulb of S. hernandifolia by the application of modern separation techniques yielded a DBBI alkaloid which was identified as cycleanine using spectroscopic methods (UV, IR, . , Mass). Cycleanine showed significant anti-inflammatory activity against carrageenin induced paw oedema, comparable to that produced by diclofenac sodium, used as standard drug. It exhibited potent analgesic effects against chemical and thermal noxious stimuli. It was also found to possess anticonvulsive activity in the strychnine induced convulsion model.

Eighty Years of Polarography – History and Future

AbstractSince 1922, when Professor Jaroslav Heyrovský carried out his pioneering experiment with a dropping mercury electrode, polarography showed remarkable ability to adjust to ever increasing demands on the sensitivity and selectivity and up to now mercury electrodes are among the best sensors for electroanalytical measurements. The aim of this contribution is to show both the historical development of these techniques and their presence and possible future developments and to show that even today in certain cases polarographic and voltammetric techniques on mercury electrodes can successfully compete with modern separation and spectrometric techniques.