Статті в журналах: "Separation techniques for silicate matrices"

1

Bonnand, P., C. Israel, M. Boyet, R. Doucelance, and D. Auclair. "Radiogenic and stable Ce isotope measurements by thermal ionisation mass spectrometry." Journal of Analytical Atomic Spectrometry 34, no. 3 (2019): 504–16. http://dx.doi.org/10.1039/c8ja00362a.

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Techniques for the separation of Cerium (Ce) from silicate matrices and for the analysis of radiogenic (ε¹³⁸Ce) and mass dependent (δ¹⁴²Ce) Ce isotope variations by Thermal Ionisation Mass Spectrometry (TIMS) are presented in this study.

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2

Muzi, Elisa, Maxime Cavillon, Matthieu Lancry, François Brisset, Ruyue Que, Diego Pugliese, Davide Janner, and Bertrand Poumellec. "Towards a Rationalization of Ultrafast Laser-Induced Crystallization in Lithium Niobium Borosilicate Glasses: The Key Role of the Scanning Speed." Crystals 11, no. 3 (March 15, 2021): 290. http://dx.doi.org/10.3390/cryst11030290.

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Femtosecond (fs)-laser direct writing is a powerful technique to enable a large variety of integrated photonic functions in glass materials. One possible way to achieve functionalization is through highly localized and controlled crystallization inside the glass volume, for example by precipitating nanocrystals with second-order susceptibility (frequency converters, optical modulators), and/or with larger refractive indices with respect to their glass matrices (graded index or diffractive lenses, waveguides, gratings). In this paper, this is achieved through fs-laser-induced crystallization of LiNbO3 nonlinear crystals inside two different glass matrices: a silicate (mol%: 33Li2O-33Nb2O5-34SiO2, labeled as LNS) and a borosilicate (mol%: 33Li2O-33Nb2O5-13SiO2-21B2O3, labeled as LNSB). More specifically, we investigate the effect of laser scanning speed on the crystallization kinetics, as it is a valuable parameter for glass laser processing. The impact of scanning energy and speed on the fabrication of oriented nanocrystals and nanogratings during fs-laser irradiation is studied.Fs-laser direct writing of crystallized lines in both LNS and LNSB glass is investigated using both optical and electron microscopy techniques. Among the main findings to highlight, we observed the possibility to maintain crystallization during scanning at speeds ~5 times higher in LNSB relative to LNS (up to ~600 µm/s in our experimental conditions). We found a speed regime where lines exhibited a large polarization-controlled retardance response (up to 200 nm in LNSB), which is attributed to the texturation of the crystal/glass phase separation with a low scattering level. These characteristics are regarded as assets for future elaboration methods and designs of photonic devices involving crystallization. Finally, by using temperature and irradiation time variations along the main laser parameters (pulse energy, pulse repetition rate, scanning speed), we propose an explanation on the origin of (1) crystallization limitation upon scanning speed, (2) laser track width variation with respect to scanning speed, and (3) narrowing of the nanogratings volume but not the heat-affected volume.

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3

Navin, Michael J., and Michael D. Morris. "Capillary Electrophoresis Separation Techniques and Mechanisms in Dilute Polymer Matrices." Journal of the Chinese Chemical Society 42, no. 1 (February 1995): 5–9. http://dx.doi.org/10.1002/jccs.199500002.

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4

Stepanova, Mariia, Aleksei Eremin, Ilia Averianov, Iosif Gofman, Antonina Lavrentieva, Viktor Korzhikov-Vlakh, and Evgenia Korzhikova-Vlakh. "Comparison of Supermacroporous Polyester Matrices Fabricated by Thermally Induced Phase Separation and 3D Printing Techniques." Key Engineering Materials 822 (September 2019): 277–83. http://dx.doi.org/10.4028/www.scientific.net/kem.822.277.

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Supermacroporous three-dimensional matrices based on poly-D,L-lactide or polycaprolactone were fabricated by thermally induced phase separation method and 3D printing technique. The morphology and mechanical properties of the resulting matrices were studied with the use of optical and scanning electron microscopy and the uniaxial compression test, respectively. All matrices were characterized with supermacroporous structure suitable for cell penetration. A significant increase in Young's modulus and tensile strength was established for both polymer matrices prepared by 3D printing technique.

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Hsu, S. h., S. Huang, Y. C. Wang, and Y. C. Kuo. "Novel nanostructured biodegradable polymer matrices fabricated by phase separation techniques for tissue regeneration." Acta Biomaterialia 9, no. 6 (June 2013): 6915–27. http://dx.doi.org/10.1016/j.actbio.2013.02.012.

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López-Cabeza, Rocío, and Antonio Francioso. "Chiral Pesticides with Asymmetric Sulfur: Extraction, Separation, and Determination in Different Environmental Matrices." Separations 9, no. 2 (January 26, 2022): 29. http://dx.doi.org/10.3390/separations9020029.

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Chiral pesticides with S atoms as asymmetric centers are gaining great importance in the search for new pesticides with new modes of action. As for the rest of the chiral pesticides, the determination of the stereoisomers separately has become crucial in the environmental risks assessment of these pesticides. Therefore, the development of suitable extraction and clean-up methods as well as efficient stereoselective analytical techniques for stereoisomers determination in environmental samples is essential. Currently, liquid/solid phase extraction, microextraction, and QuEChERS-based methods are most commonly used to obtain chiral pesticides from environmental samples. Gas, liquid, and supercritical fluid chromatography together with capillary electrophoresis techniques are the most important for the determination of the stereoisomers of chiral pesticides containing S atoms in its structure. In this study, all these techniques are briefly reviewed, and the advantages and disadvantages of each are discussed.

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Miao, Yu, Tao Long, Jingjun Wang, Fu Lai, Weiran Zuo, and Bao Guo. "The Inadvertent Activation of Silicate Minerals Flotation and Their Depression in Molybdenite Beneficiation." Minerals 11, no. 11 (November 22, 2021): 1296. http://dx.doi.org/10.3390/min11111296.

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The Wushan Operation has been studied as a case study, particularly relevant to the copper-molybdenum separation circuit, in which efforts have been made to improve the quality of the molybdenum concentrate through diagnostic analysis. A key finding has been the appearance of coarser silicate minerals in the molybdenum concentrate due to their inadvertent activation in flotation. The suitable silicate minerals flotation conditions occurs, most likely, due to upstream bulk flotation regarding the usage of novel collectors and metal cations bearing process water. The flotation of silicate minerals can be diminished by the implementation of water glass and regrinding. The mechanisms underlying flotation behaviors have been revealed by using advanced in-situ surface analysis and particle size analysis techniques.

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8

Eikenberg, J., S. Bajo, I. Zumsteg, M. Reuthi, and H. Beer. "Separation and Measurement Techniques for Determination of 228Th, 230Th and 232Th in Various Matrices." Radiation Protection Dosimetry 97, no. 2 (October 1, 2001): 127–31. http://dx.doi.org/10.1093/oxfordjournals.rpd.a006649.

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9

Raks, Victoria, Hossam Al-Suod, and Bogusław Buszewski. "Isolation, Separation, and Preconcentration of Biologically Active Compounds from Plant Matrices by Extraction Techniques." Chromatographia 81, no. 2 (September 22, 2017): 189–202. http://dx.doi.org/10.1007/s10337-017-3405-0.

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10

Tohry, Arash, Reza Dehghan, Saeed Chehreh Chelgani, Jan Rosenkranz, and Omid Rahmani. "Selective Separation of Hematite by a Synthesized Depressant in Various Scales of Anionic Reverse Flotation." Minerals 9, no. 2 (February 20, 2019): 124. http://dx.doi.org/10.3390/min9020124.

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Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. Reverse anionic flotation by using sodium silicate (SS) as an iron oxide depressant is one of the techniques for iron ore processing. This investigation is going to present a synthesized reagent “sodium co-silicate (SCS)” for hematite depression through a reverse anionic flotation. The main hypothesis is the selective depression of hematite and, simultaneously, modification of the pulp pH by SCS. Various flotation experiments, including micro-flotation, and batch flotation of laboratory and industrial scales, were conducted in order to compare the depression selectivity of SS versus SCS. Outcomes of flotation tests at the different flotation scales demonstrated that hematite depression by SCS is around 3.3% higher than by SS. Based on flotation experiment outcomes, it was concluded that SCS can modify the pH of the process at ~9.5, and the plant reagents (including NaOH, Na2CO3, and SS gel) can be replaced by just SCS, which can also lead to a higher efficiency in the plant.

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Manousi, Natalia, George Zachariadis, Eleni Deliyanni, and Victoria Samanidou. "Applications of Metal-Organic Frameworks in Food Sample Preparation." Molecules 23, no. 11 (November 6, 2018): 2896. http://dx.doi.org/10.3390/molecules23112896.

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Food samples such as milk, beverages, meat and chicken products, fish, etc. are complex and demanding matrices. Various novel materials such as molecular imprinted polymers (MIPs), carbon-based nanomaterials carbon nanotubes, graphene oxide and metal-organic frameworks (MOFs) have been recently introduced in sample preparation to improve clean up as well as to achieve better recoveries, all complying with green analytical chemistry demands. Metal-organic frameworks are hybrid organic inorganic materials, which have been used for gas storage, separation, catalysis and drug delivery. The last few years MOFs have been used for sample preparation of pharmaceutical, environmental samples and food matrices. Due to their high surface area MOFs can be used as adsorbents for the development of sample preparation techniques of food matrices prior to their analysis with chromatographic and spectrometric techniques with great performance characteristics.

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12

Bogos, Luisa-Gabriela, Ioana-Ecaterina Pralea, Radu-Cristian Moldovan, and Cristina-Adela Iuga. "Indirect Enantioseparations: Recent Advances in Chiral Metabolomics for Biomedical Research." International Journal of Molecular Sciences 23, no. 13 (July 4, 2022): 7428. http://dx.doi.org/10.3390/ijms23137428.

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Chiral metabolomics is starting to become a well-defined research field, powered by the recent advances in separation techniques. This review aimed to cover the most relevant advances in indirect enantioseparations of endogenous metabolites that were published over the last 10 years, including improvements and development of new chiral derivatizing agents, along with advances in separation methodologies. Moreover, special emphasis is put on exciting advances in separation techniques combined with mass spectrometry, such as chiral discrimination by ion-mobility mass spectrometry together with untargeted strategies for profiling of chiral metabolites in complex matrices. These advances signify a leap in chiral metabolomics technologies that will surely offer a solid base to better understand the specific roles of enantiomeric metabolites in systems biology.

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13

Gad, Hamdi Mohamed Hassan, Sh Labib, and M. I. Aly. "Synthesis, Characterization and Application of Nano-adsorbent Materials in the Sorption of Pb(II), Ni(II), Co(II), Mn(II), Li(I) from Aqueous Solution." JOURNAL OF ADVANCES IN CHEMISTRY 10, no. 8 (August 2, 2014): 3053–67. http://dx.doi.org/10.24297/jac.v10i8.2256.

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In this study, nano-adsorbent materials were synthesized from two different precursors by thermal activation technique. The first was the synthesizing of nano-zinc silicate from chemical reagents of zinc oxide and commercial silica gel. The second was the preparation of nano-pore size activated carbon from different biomass. The synthesized nano-adsorbent materials were characterized by different techniques; Surface Area, FTIR, XRD and SEM. The prepared nano-adsorbent materials were applied in the sorption and separation of some heavy metals from aqueous solution. These metals includes; Pb (II), Ni(II), Co(II), Mn(II) and Li(I). Some factors affecting on the sorption process (e.g. contact time and pH) were investigated. It was found that: the nano-zinc silicate (of ratio 1:1 thermally treated at 700 0C) and nano-pores activated carbon (prepared from saw dust impregnated with 70% H3PO4 overnight, then heated to 500 0C in presence of steam for 80 min.) were the best samples for sorption and separation of concerned heavy metals.

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14

Constantin, Oana Emilia, and Daniela Ionela Istrati. "Extraction, Quantification and Characterization Techniques for Anthocyanin Compounds in Various Food Matrices—A Review." Horticulturae 8, no. 11 (November 16, 2022): 1084. http://dx.doi.org/10.3390/horticulturae8111084.

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Anthocyanins are water-soluble pigments characterized by various intense colors found in fruits and vegetables. Scientific studies have shown growing evidence to support their health benefits. Therefore, estimating the anthocyanin content in food is essential to identify the ideal analytical method. Moreover, due to the instability of plant anthocyanins, it is important to select and optimize their extraction, separation and qualitative and quantitative analysis, steps that are indispensable and important in their study. The present article reviews the latest procedures for extracting anthocyanins from various food matrices and analytical methods for their quantification. Therefore, various forms of preliminary treatments of samples for anthocyanin extraction, extraction procedures for various fruits, vegetables and cereals, purification of samples and quantification of anthocyanins are highlighted and evaluated. Using ultrasound-assisted extraction (UAE) might be effective for anthocyanin extraction and the Amberlite XAD-7HP method is the most effective for purifying anthocyanins. Combining the liquid chromatography (LC) method with electrospray ionization (ESI) and mass spectrometry (MS) or quadrupole time-of-flight (QTOF) with mass spectrometry (MS) better quantifies the anthocyanins in the food complex samples. Therefore, the extraction and separation of anthocyanins and their qualitative and quantitative analyses are essential steps in their research. As a result, the study concentrates on a detailed characterization of various qualitative and quantitative analytical methodologies, while briefly describing the main anthocyanin extraction processes.

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15

Mu, Lingli, Feifan Xie, Sanwang Li, and Peng Yu. "Determination of Strong Acidic Drugs in Biological Matrices: A Review of Separation Methods." Chromatography Research International 2014 (September 29, 2014): 1–10. http://dx.doi.org/10.1155/2014/469562.

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Strong acidic drugs are a class of chemical compounds that normally have high hydrophilicity and large negative charges, such as organophosphatic compounds and organosulphonic compounds. This review focuses on sample preparation and separation methods for this group of compounds in biological matrices in recent years. A wide range of separation techniques, especially chromatographic method, are presented and critically discussed, which include liquid chromatography (e.g., ion-pair and ion-exchange chromatography), capillary electrophoresis (CE), and other types. Due to the extremely low concentration level of target analytes as well as the complexity of biological matrices, sample pretreatment methods, such as dilute and shoot methods, protein precipitation (PP), liquid-liquid extraction (LLE), solid-phase extraction (SPE), degradation, and derivatization strategy, also play important roles for the development of successful analytical methods and thus are also discussed.

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16

Thomas, Daniela, Berit Schütze, Wiebke Mareile Heinze, and Zacharias Steinmetz. "Sample Preparation Techniques for the Analysis of Microplastics in Soil—A Review." Sustainability 12, no. 21 (October 31, 2020): 9074. http://dx.doi.org/10.3390/su12219074.

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Although most plastic pollution originates on land, current research largely remains focused on aquatic ecosystems. Studies pioneering terrestrial microplastic research have adapted analytical methods from aquatic research without acknowledging the complex nature of soil. Meanwhile, novel methods have been developed and further refined. However, methodical inconsistencies still challenge a comprehensive understanding of microplastic occurrence and fate in and on soil. This review aims to disentangle the variety of state-of-the-art sample preparation techniques for heterogeneous solid matrices to identify and discuss best-practice methods for soil-focused microplastic analyses. We show that soil sampling, homogenization, and aggregate dispersion are often neglected or incompletely documented. Microplastic preconcentration is typically performed by separating inorganic soil constituents with high-density salt solutions. Not yet standardized but currently most used separation setups involve overflowing beakers to retrieve supernatant plastics, although closed-design separation funnels probably reduce the risk of contamination. Fenton reagent may be particularly useful to digest soil organic matter if suspected to interfere with subsequent microplastic quantification. A promising new approach is extraction of target polymers with organic solvents. However, insufficiently characterized soils still impede an informed decision on optimal sample preparation. Further research and method development thus requires thorough validation and quality control with well-characterized matrices to enable robust routine analyses for terrestrial microplastics.

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17

Selahle, Shirley Kholofelo, Anele Mpupa, and Philiswa Nosizo Nomngongo. "A review of extraction, analytical, and advanced methods for the determination of neonicotinoid insecticides in environmental water matrices." Reviews in Analytical Chemistry 40, no. 1 (January 1, 2021): 187–203. http://dx.doi.org/10.1515/revac-2021-0134.

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Abstract Neonicotinoid insecticides are widely used to kill and prevent unwanted insects from attacking growing crops. Extensive use of insecticides in various compartments of the environment has led to adverse effect on the health of living organisms. Several analytical methodologies have been reported for extraction and quantification of neonicotinoid insecticides in various matrices. The analytical detection techniques range from traditional to modern or state of the art quantification methods. The traditional analytical techniques include gas chromatography and high-performance liquid chromatography. These methods require extensive sample pretreatment before identification, separation, and quantification of target analytes. Advanced detection techniques refer to the sensor technologies based on optical, biorecognition, molecular imprinted polymers chemical, and piezoelectric. In this review, a summary and explanation of the various traditional analytical and advanced methodologies for extraction, separation, detection, and quantification of neonicotinoid insecticides residue in water samples have been discussed.

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18

Loy, Chee W., Khamirul A. Matori, Norhazlin Zainuddin, Andrew E. Whitten, Christine Rehm, Liliana de Campo, Anna Sokolova, and Siegbert Schmid. "Crystallographic characterization of fluorapatite glass-ceramics synthesized from industrial waste." Powder Diffraction 32, S2 (September 5, 2017): S61—S65. http://dx.doi.org/10.1017/s088571561700094x.

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A series of phase transformations of a novel fluoroaluminosilicate glass forming a range of fluorapatite glass-ceramics on sintering are reported. The sintering process induces formation of fluorapatite, mullite, and anorthite phases within the amorphous silicate matrices of the glass-ceramics. The fluoroaluminosilicate glass, SiO2–Al2O3–P2O5–CaO–CaF2, is prepared from waste materials, such as rice husk ash, pacific oyster shells, and disposable aluminium cans. The thermally induced crystallographic and microstructure evolution of the fluoroaluminosilicate glass towards the fluorapatite glass-ceramics, with applications in dental and bone restoration, are investigated by powder X-ray diffraction and small-angle neutron-scattering techniques.

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19

Proulx, Kim, and Kevin J. Wilkinson. "Separation, detection and characterisation of engineered nanoparticles in natural waters using hydrodynamic chromatography and multi-method detection (light scattering, analytical ultracentrifugation and single particle ICP-MS)." Environmental Chemistry 11, no. 4 (2014): 392. http://dx.doi.org/10.1071/en13232.

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Environmental context The effects of engineered nanoparticles on the environment and on human health are difficult to evaluate largely because nanoparticles are so difficult to measure. The main problems are that concentrations are low and the engineered nanoparticles are often difficult to distinguish from the environmental matrices in which they are found. We report a separation technique that facilitates the detection of engineered nanoparticles in natural waters. Abstract Few analytical techniques are presently able to detect and quantify engineered nanoparticles (ENPs) in the environment. The major challenges result from the complex matrices of environmental samples and the low concentrations at which the ENPs are expected to be found. Separation techniques such as asymmetric flow field flow fractionation (AF4) and more recently, hydrodynamic chromatography (HDC) have been used to partly resolve ENPs from their complex environmental matrices. In this paper, HDC was first coupled to light scattering detectors in order to develop a method that would allow the separation and detection of ENPs spiked into a natural water. Size fractionated samples were characterised using off-line detectors including analytical ultracentrifugation (AUC), dynamic light scattering (DLS) and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). HDC was able to separate a complex mixture of polystyrene, silver and gold nanoparticles (radii of 60, 40, 20 and 10nm) contained within a river water matrix. Furthermore, the feasibility of using HDC coupled to SP-ICP-MS was demonstrated by detecting 4µgL–1 of a 20-nm (radius) nAg in a river water sample.

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Khan, Mohammad Sharif, Jannatul Azmir, Ademario Iris da Silva Junior, Yong Foo Wong, Mamun Mollah, Jalal T. Althakafy, and Md Zaidul Islam Sarker. "Strategy for Sustainable and Green Chromatographic Separation Science: Innovation, Technology and Application." Current Chromatography 7, no. 1 (November 26, 2020): 5–16. http://dx.doi.org/10.2174/2213240607999200813195405.

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Green separation science involves extraction, pre-concentration and chromatographic analysis aiming at minimizing environmental impact by reducing energy and reagent usage and reducing or eliminating waste generation. However, the enrichment of trace analytes and/or the analysis of complex matrices most frequently require several steps before analysis, such as extraction, pre-concentration, clean up and preparative chromatography. Thus, alternative and greener separation techniques and solvents are replacing classical methods to diminish the carbon footprint and increase sustainability. Moreover, many innovations are also emerging to curtail the environmental impact of samples analysis; such as micro or nano analytical platforms, sensor-based systems and direct injection to high-resolution mass spectrometry. The current review provides an updated account of the green and sustainable separation science techniques. The current innovations on greener separations and their application in different fields of study are discussed.

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Sidana, Jasmeen, and Lokesh Kumar Joshi. "Recycle HPLC: A Powerful Tool for the Purification of Natural Products." Chromatography Research International 2013 (November 6, 2013): 1–7. http://dx.doi.org/10.1155/2013/509812.

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Natural compounds occur as various isomeric or closely related structures in biological matrices. These compounds are difficult to separate from the complex mixtures, and hence, the need for effective and innovative separation techniques arises. Recycle HPLC allows the recycling of sample, in part or full, and increases the separation efficiency of the process while keeping the peak dispersion to a minimum. Recycling in an HPLC system has been used in the isolation and purification of different types of natural products including enantiomers, diastereomers, epimers, positional isomers, and structurally related or unrelated compounds having similar retention characteristics. The present paper overviews the development of instrumentation and setup of recycle HPLC and its applications in the separation of natural products.

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Mejía-Carmona, Karen, Marcela Jordan-Sinisterra, and Fernando Lanças. "Current Trends in Fully Automated On-Line Analytical Techniques for Beverage Analysis." Beverages 5, no. 1 (February 1, 2019): 13. http://dx.doi.org/10.3390/beverages5010013.

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The determination of target analytes in complex matrices such as beverages requires a series of analytical steps to obtain a reliable analysis. This critical review presents the current trends in sample preparation techniques based on solid phase extraction miniaturization, automation and on-line coupling. Techniques discussed include solid-phase extraction (SPE), solid-phase microextraction (SPME), in-tube solid-phase microextraction (in-tube SPME) and turbulent-flow chromatography (TFC). Advantages and limitations, as well as several of their main applications in beverage samples are discussed. Finally, fully automated on-line systems that involve extraction, chromatographic separation, and tandem mass spectrometry in one-step are introduced and critically reviewed.

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Amaral, Michelle S. S., and Philip J. Marriott. "The Blossoming of Technology for the Analysis of Complex Aroma Bouquets—A Review on Flavour and Odorant Multidimensional and Comprehensive Gas Chromatography Applications." Molecules 24, no. 11 (May 31, 2019): 2080. http://dx.doi.org/10.3390/molecules24112080.

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Multidimensional approaches in gas chromatography have been established as potent tools to (almost) attain fully resolved analyses. Flavours and odours are important application fields for these techniques since they include complex matrices, and are of interest for both scientific study and to consumers. This article is a review of the main research studies in the above theme, discussing the achievements and challenges that demonstrate a maturing of analytical separation technology.

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Schlosser, Gitta, Petr Kačer, Marek Kuzma, ZoltÃ¯Â¿Â½n SzilÃ¯Â¿Â½gyi, Alida Sorrentino, Carla Manzo, Rosa Pizzano, Livia Malorni, and Gabriella Pocsfalvi. "Coupling Immunomagnetic Separation on Magnetic Beads with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Detection of Staphylococcal Enterotoxin B." Applied and Environmental Microbiology 73, no. 21 (September 7, 2007): 6945–52. http://dx.doi.org/10.1128/aem.01136-07.

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ABSTRACT The growing importance of mass spectrometry for the identification and characterization of bacterial protein toxins is a consequence of the improved sensitivity and specificity of mass spectrometry-based techniques, especially when these techniques are combined with affinity methods. Here we describe a novel method based on the use of immunoaffinity capture and matrix-assisted laser desorption ionization-time of flight mass spectrometry for selective purification and detection of staphylococcal enterotoxin B (SEB). SEB is a potent bacterial protein toxin responsible for food poisoning, as well as a potential biological warfare agent. Unambiguous detection of SEB at low-nanogram levels in complex matrices is thus an important objective. In this work, an affinity molecular probe was prepared by immobilizing anti-SEB antibody on the surface of para-toluene-sulfonyl-functionalized monodisperse magnetic particles and used to selectively isolate SEB. Immobilization and affinity capture procedures were optimized to maximize the density of anti-SEB immunoglobulin G and the amount of captured SEB, respectively, on the surface of magnetic beads. SEB could be detected directly “on beads” by placing the molecular probe on the matrix-assisted laser desorption ionization target plate or, alternatively, “off beads” after its acidic elution. Application of this method to complex biological matrices was demonstrated by selective detection of SEB present in different matrices, such as cultivation media of Staphylococcus aureus strains and raw milk samples.

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Das, Ruchita, and Y. K. Agrawal. "Trends and Advances in Separation and Detection of SSRIs and SNRIs in Biological Matrices." Chromatography Research International 2013 (October 31, 2013): 1–15. http://dx.doi.org/10.1155/2013/139459.

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Nowadays antidepressant drugs like selective serotonin reuptake inhibitors (SSRIs) and selective norepinephrine reuptake inhibitors (SNRIs) represent the first choice in the treatment of moderate to severe depressive illness, various phobias, and personality disorders. In spite of the therapeutic aspects, they often produce very severe and toxic effects in deliberate and accidental cases of poisoning. These are also considered as date-rape drugs used for drugged victims for raping or robbing. Therefore, in recent years, their analyses in different biological matrices for clinical and toxicological analysis purposes has been a target worthy of interest. Thus, the review focuses on recent advancements of various separation techniques like chromatography and electrophoresis that are concernd with the determination of selective serotonin reuptake inhibitor and selective norepinephrine reuptake inhibitor drugs and their metabolites in various biological matrices. In addition to this, a critical discussion on analytical approaches has also been incorporated, suggesting their applicability and limitations for further implementations. Thus, this paper will definitely help in the selection and development of proper analytical methodologies to achieve satisfactory results, better scientific understanding, and test interpretation.

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Dang, Huynh N. P., and Joselito P. Quirino. "Analytical Separation of Carcinogenic and Genotoxic Alkenylbenzenes in Foods and Related Products (2010–2020)." Toxins 13, no. 6 (May 28, 2021): 387. http://dx.doi.org/10.3390/toxins13060387.

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Alkenylbenzenes are potentially toxic (genotoxic and carcinogenic) compounds present in plants such as basil, tarragon, anise star and lemongrass. These plants are found in various edible consumer products, e.g., popularly used to flavour food. Thus, there are concerns about the possible health consequences upon increased exposure to alkenylbenzenes especially due to food intake. It is therefore important to constantly monitor the amounts of alkenylbenzenes in our food chain. A major challenge in the determination of alkenylbenzenes in foods is the complexity of the sample matrices and the typically low amounts of alkenylbenzenes present. This review will therefore discuss the background and importance of analytical separation methods from papers reported from 2010 to 2020 for the determination of alkenylbenzenes in foods and related products. The separation techniques commonly used were gas and liquid chromatography (LC). The sample preparation techniques used in conjunction with the separation techniques were various variants of extraction (solvent extraction, liquid-liquid extraction, liquid-phase microextraction, solid phase extraction) and distillation (steam and hydro-). Detection was by flame ionisation and mass spectrometry (MS) in gas chromatography (GC) while in liquid chromatography was mainly by spectrophotometry.

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Armstrong, Cheryl M., Andrew G. Gehring, George C. Paoli, Chin-Yi Chen, Yiping He, and Joseph A. Capobianco. "Impacts of Clarification Techniques on Sample Constituents and Pathogen Retention." Foods 8, no. 12 (December 3, 2019): 636. http://dx.doi.org/10.3390/foods8120636.

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Determination of the microbial content in foods is important, not only for safe consumption, but also for food quality, value, and yield. A variety of molecular techniques are currently available for both identification and quantification of microbial content within samples; however, their success is often contingent upon proper sample preparation when the subject of investigation is a complex mixture of components such as foods. Because of the importance of sample preparation, the present study employs a systematic approach to compare the effects of four different separation techniques (glass wool, 50 μm polypropylene filters, graphite felt, and continuous flow centrifugation (CFC)) on sample preparation. To define the physical effects associated with the use of these separation methods, a multifactorial analysis was performed where particle size and composition, both pre- and post- processing, were analyzed for four different food matrices including lean ground beef, ground pork, ground turkey and spinach. Retention of three important foodborne bacterial pathogens (Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes) was also examined to evaluate the feasibility of the aforementioned methods to be utilized within the context of foodborne pathogen detection. Data from the multifactorial analysis not only delineated the particle size ranges but also defined the unique compositional profiles and quantified the bacterial retention. The three filtration membranes allowed for the passage of bacteria with minimal loss while CFC concentrated the inoculated bacteria. In addition, the deposition and therefore concentration of food matrix observed with CFC was considerably higher for meat samples relative to spinach. However, filtration with glass wool prior to CFC helped clarify meat samples, which led to considerably lower amounts of solids in the CFC vessel post processing and an increase in the recovery of the bacteria. Overall, by laying a framework for the deductive selection of sample preparation techniques, the results of the study can be applied to a range of applications where it would be beneficial to scientifically guide the pairing of the criteria associated with a downstream detection method with the most advantageous sample preparation techniques for complex matrices such as foods.

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Kraševec, Ida, and Helena Prosen. "Solid-Phase Extraction of Polar Benzotriazoles as Environmental Pollutants: A Review." Molecules 23, no. 10 (September 29, 2018): 2501. http://dx.doi.org/10.3390/molecules23102501.

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Анотація:

Polar benzotriazoles are corrosion inhibitors with widespread use; they are environmentally characterized as emerging pollutants in the water system, where they are present in low concentrations. Various extraction methods have been used for their separation from various matrices, ranging from classical liquid–liquid extractions to various microextraction techniques, but the most frequently applied extraction technique remains the solid-phase extraction (SPE), which is the focus of this review. We present an overview of the methods, developed in the last decade, applied for the determination of benzotriazoles in aqueous and solid environmental samples. Several other matrices, such as human urine and plant material, are also considered in the text. The methods are reviewed according to the determined compounds, sample matrices, cartridges and eluents used, extraction recoveries and the achieved limits of quantification. A critical evaluation of the advantages and drawbacks of the published methods is given.

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D’Ovidio, Cristian, Martina Bonelli, Enrica Rosato, Angela Tartaglia, Halil İbrahim Ulusoy, Victoria Samanidou, Kenneth G. Furton, et al. "Novel Applications of Microextraction Techniques Focused on Biological and Forensic Analyses." Separations 9, no. 1 (January 15, 2022): 18. http://dx.doi.org/10.3390/separations9010018.

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In recent years, major attention has been focused on microextraction procedures that allow high recovery of target analytes, regardless of the complexity of the sample matrices. The most used techniques included liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME), dispersive liquid-liquid microextraction (DLLME), microextraction by packed sorbent (MEPS), and fabric-phase sorptive extraction (FPSE). These techniques manifest a rapid development of sample preparation techniques in different fields, such as biological, environmental, food sciences, natural products, forensic medicine, and toxicology. In the biological and forensic fields, where a wide variety of drugs with different chemical properties are analyzed, the sample preparation is required to make the sample suitable for the instrumental analysis, which often includes gas chromatography (GC) and liquid chromatography (LC) coupled with mass detectors or tandem mass detectors (MS/MS). In this review, we have focused our attention on the biological and forensic application of these innovative procedures, highlighting the major advantages and results that have been accomplished in laboratory and clinical practice.

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30

Chiriac, Elena, Carmen Chiţescu, Elisabeta-Irina Geană, Cerasela Gird, Radu Socoteanu, and Rica Boscencu. "Advanced Analytical Approaches for the Analysis of Polyphenols in Plants Matrices—A Review." Separations 8, no. 5 (May 12, 2021): 65. http://dx.doi.org/10.3390/separations8050065.

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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. This paper summarizes current advances in the state of the art for polyphenols identification and quantification. Analytical techniques ranging from high-pressure liquid chromatography to hyphenated spectrometric methods are discussed. The topic of high-resolution mass spectrometry, from targeted quantification to untargeted comprehensive chemical profiling, is particularly addressed. Structure elucidation is one of the important steps for natural products research. Mass spectral data handling approaches, including acquisition mode selection, accurate mass measurements, elemental composition, mass spectral library search algorithms and structure confirmation through mass fragmentation pathways, are discussed.

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Park, Ilhwan, Seunggwan Hong, Sanghee Jeon, Mayumi Ito, and Naoki Hiroyoshi. "A Review of Recent Advances in Depression Techniques for Flotation Separation of Cu–Mo Sulfides in Porphyry Copper Deposits." Metals 10, no. 9 (September 21, 2020): 1269. http://dx.doi.org/10.3390/met10091269.

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Porphyry copper deposits (PCDs) are some of the most important sources of copper (Cu) and molybdenum (Mo). Typically, the separation and recovery of chalcopyrite (CuFeS2) and molybdenite (MoS2), the major Cu and Mo minerals, respectively, in PCDs are achieved by two-step flotation involving (1) bulk flotation to separate Cu–Mo concentrates and tailings (e.g., pyrite, silicate, and aluminosilicate minerals) and (2) Cu–Mo flotation to separate chalcopyrite and molybdenite. In Cu–Mo flotation, chalcopyrite is depressed using Cu depressants, such as NaHS, Na2S, Nokes reagent (P2S5 + NaOH), and NaCN, meaning that it is recovered as tailings, while molybdenite is floated and recovered as froth product. Although conventionally used depressants are effective in the separation of Cu and Mo, they have the potential to emit toxic and deadly gases such as H2S and HCN when operating conditions are not properly controlled. To address these problems caused by the use of conventional depressants, many studies aimed to develop alternative methods of depressing either chalcopyrite or molybdenite. In this review, recent advances in chalcopyrite and molybdenite depressions for Cu–Mo flotation separation are reviewed, including alternative organic and inorganic depressants for Cu or Mo, as well as oxidation-treatment technologies, such as ozone (O3), plasma, hydrogen peroxide (H2O2), and electrolysis, which create hydrophilic coatings on the mineral surface.

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Pardo, Antonelle, Laetitia Mespouille, Philippe Dubois, Pierre Duez, and Bertrand Blankert. "Targeted extraction of active compounds from natural products by molecularly imprinted polymers." Open Chemistry 10, no. 3 (June 1, 2012): 751–65. http://dx.doi.org/10.2478/s11532-012-0018-1.

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AbstractOne of the most promising separation techniques that have emerged during the last decade is based on the use of molecularly imprinted polymers (MIPs). MIPs are stable polymers that possess specific cavities designed for a template molecule, endowed with excellent selectivity compared to regular solid phase extraction techniques. Molecularly imprinted solid-phase extraction (MISPE) has already shown a high efficiency for the sample preparation from complex matrices. Natural products received huge attention in recent years. Indeed, the application of MISPE for the screening of natural products appears extremely interesting not only for the selective extraction of a target compound but also for the concomitant discovery of new drug candidates, promising sources of therapeutic benefits. In the present review, examples of recognition and separation of active components from natural extracts are emphasized. MIPs are very promising materials to mimic the recognition characteristics exhibited by enzymes or receptors although further developments are necessary to fully exploit their wide potential.

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Rajib, Mohammad, Md Fahad Hossain, and Mahfuza Parveen. "Glass Production from River Silica of Bangladesh: Converting Waste to Economically Potential Natural Resource." Environment and Natural Resources Journal 20, no. 2 (December 7, 2021): 1–8. http://dx.doi.org/10.32526/ennrj/20/202100124.

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Анотація:

The Ganges-Brahmaputra river system at the Bengal Basin carries large amounts of sediments on the way to finally deposit at the Bay of Bengal. Those river-transported sediments form bar deposits during dry season in many areas of Bangladesh and accumulate economic mineral depositions at suitable geological environments. Dredging is a must for most of those rivers for proper navigation, as well as protecting bank erosion, which generates millions of tons of waste sand. The dredged materials from river beds are mostly composed of silicate minerals, especially quartz and feldspar along with several dark colored heavy minerals. Like the industrial processing of heavy minerals from bulk sands, various physical separation techniques can be utilized for the beneficiation of silica from those river-born silicate minerals in dredged sands. Those silica have been successfully upgraded to near-glass sand grade in the laboratory, however, they have yet to be utilized for any kind of commercial venture. The present study attempts characterization of several river sands through physical separation and laboratory analysis. The upgraded silica was successfully compared with several quality glass sands and laboratory production of glasses. This experimental production of glass from upgraded silica could potentially be economical considering its industrial application with positive environmental consequences through minimizing the dredging cost, increasing the navigability of the river and ecological balance along the flood plain.

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Ayinla, Kuranga Ibrahim, Alafara Abdullahi Baba, Bankim Chandra Tripathy, Malay Kumar Ghosh, Rajan Kumar Dwari, and Subrat Kumar Padhy. "Enrichment of a Nigerian chromite ore for metallurgical application by dense medium flotation and magnetic separation." Metallurgical Research & Technology 116, no. 3 (2019): 324. http://dx.doi.org/10.1051/metal/2018097.

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This study, focused on the beneficiation of a Nigerian complex chromite ore sourced from Tunga-Kaduka, Anka Local Government of Zamfara State, Nigeria, assaying 45.85% Cr2O4 and 54.15% mineral impurities, was enriched concurrently through sink floatation and magnetic separation techniques. The chromite ore initially analyzed to contain silicate impurities was found not suitable for metallurgical purposes. Thus, enrichment was examined through gravity separation studies using organic liquid with different specific gravities at 2.8, 3.3, and 4.0. The separation of chromite ore with lowest particle size fraction was done using Mozley mineral separator followed by the magnetic separation of the sink product by magnetic separator. The results obtained revealed about 77% of the total material containing 300 μm particle size, 52% ˂ 212 μm and 17% below 75 μm. Subsequent analysis of the beneficiated ore was carried out by wet chemical analysis and atomic absorption spectrophotometer. The results showed that Cr2O4 content increased to 78.34% from initial 45.83% with maximum Cr:Fe ratio of 3.2:1, representing 84.27% of chromium metal present in the ore. The enrichment of Cr2O4 obtained in this study could be found metallurgically applicable in the electro-deposition and ferro-chromium alloy production practices.

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35

Tesoro, Carmen, Filomena Lelario, Rosanna Ciriello, Giuliana Bianco, Angela Di Capua, and Maria Assunta Acquavia. "An Overview of Methods for L-Dopa Extraction and Analytical Determination in Plant Matrices." Separations 9, no. 8 (August 17, 2022): 224. http://dx.doi.org/10.3390/separations9080224.

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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. This paper aims to give information on the latest developments in the chemical study of L-dopa, emphasizing the extraction, separation and characterization of this compound by chromatographic, electrochemical and spectral techniques. This study can help select the best possible strategy for determining L-dopa in plant matrices using advanced analytical methods.

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36

Partridge, Ivana K., and George M. Maistros. "Phase Separation in Thermosetting Blends Studied by Dynamic Dielectric Analysis." High Performance Polymers 8, no. 1 (March 1996): 1–17. http://dx.doi.org/10.1088/0954-0083/8/1/001.

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Phase separation in unreinforced reactive blends has been studied using a variety of experimental techniques. A brief review of such studies is given, followed by a detailed description of the theory and practical applications of the new technique of dynamic dielectric analysis, DDA, as used in this context. Methods of data analysis and the extent of information available from in situ, real-time, measurements by dynamic dielectric analysis are illustrated by examples of results on model blends of simple epoxy/hardener mixtures with CTBN or POP rubber, or thermoplastic PES or PMMA. Deliberate ion doping is shown to enhance the phase separation features in the dielectric signal. Data are also presented on complex commercial thermoset/thermoplastic blends utilized as the resin matrices in carbon fibre pre-preg systems. Phase separation in a blend of epoxy and thermoplastic PEI can be studied by DDA within a glass fibre composite; this presents no additional difficulty compared with the studies of the corresponding unreinforced blend.

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Abou-Elwafa Abdallah, Mohamed. "Advances in Instrumental Analysis of Brominated Flame Retardants: Current Status and Future Perspectives." International Scholarly Research Notices 2014 (October 29, 2014): 1–21. http://dx.doi.org/10.1155/2014/651834.

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Анотація:

This review aims to highlight the recent advances and methodological improvements in instrumental techniques applied for the analysis of different brominated flame retardants (BFRs). The literature search strategy was based on the recent analytical reviews published on BFRs. The main selection criteria involved the successful development and application of analytical methods for determination of the target compounds in various environmental matrices. Different factors affecting chromatographic separation and mass spectrometric detection of brominated analytes were evaluated and discussed. Techniques using advanced instrumentation to achieve outstanding results in quantification of different BFRs and their metabolites/degradation products were highlighted. Finally, research gaps in the field of BFR analysis were identified and recommendations for future research were proposed.

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Trivedi, Neerja, Helen Erickson, Veenu Bala, Yashpal Chhonker, and Daryl Murry. "A Concise Review of Liquid Chromatography-Mass Spectrometry-Based Quantification Methods for Short Chain Fatty Acids as Endogenous Biomarkers." International Journal of Molecular Sciences 23, no. 21 (November 3, 2022): 13486. http://dx.doi.org/10.3390/ijms232113486.

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Анотація:

Fatty acids are widespread naturally occurring compounds, and essential constituents for living organisms. Short chain fatty acids (SCFAs) appeared as physiologically relevant metabolites for their involvement with gut microbiota, immunology, obesity, and other pathophysiological functions. This has raised the demand for reliable analytical detection methods in a variety of biological matrices. Here, we describe an updated overview of sample pretreatment techniques and liquid chromatography-mass spectrometry (LC-MS)-based methods for quantitative analysis of SCFAs in blood, plasma, serum, urine, feces and bacterial cultures. The present review incorporates various procedures and their applications to help researchers in choosing crucial parameters, such as pretreatment for complex biological matrices, and variables for chromatographic separation and detection, to establish a simple, sensitive, and robust quantitative method to advance our understanding of the role of SCFAs in human health and disease as potential biomarkers.

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Manousi, Natalia, Orfeas-Evangelos Plastiras, Natasa Kalogiouri, Constantinos Zacharis, and George Zachariadis. "Metal-Organic Frameworks in Bioanalysis: Extraction of Small Organic Molecules." Separations 8, no. 5 (May 4, 2021): 60. http://dx.doi.org/10.3390/separations8050060.

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The quantitative determination of xenobiotic compounds, as well as biotics in biological matrices, is generally described with the term bioanalysis. Due to the complexity of biofluids, in combination with the low concentration of the small molecules, their determination in biological matrices is a challenging procedure. Apart from the conventional solid-phase extraction, liquid-liquid extraction, protein precipitation, and direct injection approaches, nowadays, a plethora of microextraction and miniaturized extraction techniques have been reported. Furthermore, the development and evaluation of novel extraction adsorbents for sample preparation has become a popular research field. Metal-organic frameworks (MOFs) are novel materials composed of metal ions or clusters in coordination with organic linkers. Unequivocally, MOFs are gaining more and more attention in analytical chemistry due to their superior properties, including high surface area and tunability of pore size and functionality. This review discusses the utilization of MOFs in the sample preparation of biological samples for the green extraction of small organic molecules. Their common preparation and characterization strategies are discussed, while emphasis is given to their applications for green sample preparation.

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Almeida, Cristina M. M. "Overview of Sample Preparation and Chromatographic Methods to Analysis Pharmaceutical Active Compounds in Waters Matrices." Separations 8, no. 2 (February 9, 2021): 16. http://dx.doi.org/10.3390/separations8020016.

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Анотація:

In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.

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Hagarová, Ingrid, Lucia Nemček, Martin Šebesta, Ondřej Zvěřina, Peter Kasak, and Martin Urík. "Preconcentration and Separation of Gold Nanoparticles from Environmental Waters Using Extraction Techniques Followed by Spectrometric Quantification." International Journal of Molecular Sciences 23, no. 19 (September 28, 2022): 11465. http://dx.doi.org/10.3390/ijms231911465.

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The quantification of gold nanoparticles (AuNP) in environmental samples at ultratrace concentrations can be accurately performed by sophisticated and pricey analytical methods. This paper aims to challenge the analytical potential and advantages of cheaper and equally reliable alternatives that couple the well-established extraction procedures with common spectrometric methods. We discuss several combinations of techniques that are suitable for separation/preconcentration and quantification of AuNP in complex and challenging aqueous matrices, such as tap, river, lake, brook, mineral, and sea waters, as well as wastewaters. Cloud point extraction (CPE) has been successfully combined with electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma mass spectrometry (ICP-MS), chemiluminescence (CL), and total reflection X-ray fluorescence spectrometry (TXRF). The major advantage of this approach is the ability to quantify AuNP of different sizes and coatings in a sample with a volume in the order of milliliters. Small volumes of sample (5 mL), dispersive solvent (50 µL), and extraction agent (70 µL) were reported also for surfactant-assisted dispersive liquid–liquid microextraction (SA-DLLME) coupled with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). The limits of detection (LOD) achieved using different combinations of methods as well as enrichment factors (EF) varied greatly, being 0.004–200 ng L−1 and 8–250, respectively.

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Nava, Veronica, and Barbara Leoni. "Comparison of Different Procedures for Separating Microplastics from Sediments." Water 13, no. 20 (October 13, 2021): 2854. http://dx.doi.org/10.3390/w13202854.

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The separation of microplastics from environmental matrices is still challenging, especially for sediments where microplastics can accumulate affecting benthic organisms. Many authors have adopted different procedures, but their effectiveness has been rarely compared. The present study aims to compare the recovery rate of three different methodologies for the separation of dense microplastics from fine sediments and provide insights about contamination processes occurring in microplastic separation techniques. The protocols tested are a density separation method with NaCl and NaI, a density separation with NaI followed by a centrifugation step, and a digestion method with 10%KOH (m/v). The recovery yields of two high-density polymers of three different dimensional classes were tested. The highest recovery rate was reported for the first protocol. However, this method proved to be expensive, and unsatisfactory results were found when using merely NaCl. The digestion method was the one that was proven to be simple, reproducible, and affordable. The contamination tests highlighted as multiple filtration steps can increase the number of fibers deriving from airborne contamination. Since a unified approach for microplastic separation from sediments is still not selected, this study is of paramount importance as it provides data about the reliability of different methods widely adopted.

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JBARI, ATMAN, ABDELLAH ADIB, and DRISS ABOUTAJDINE. "BLIND AUDIO SEPARATION AND CONTENT ANALYSIS IN THE TIME-SCALE DOMAIN." International Journal of Semantic Computing 01, no. 03 (September 2007): 307–18. http://dx.doi.org/10.1142/s1793351x07000184.

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Анотація:

In this paper, we address the problem of Blind Audio Separation (BAS) by content evaluation of audio signals in the Time-Scale domain. Most of the proposed techniques rely on independence or at least uncorrelation assumption of the source signals exploiting mutual information or second/high order statistics. Here, we present a new algorithm, for instantaneous mixture, that considers only different time-scale source signature properties. Our approach lies in wavelet transformation advantages and proposes for this a new representation; Spatial Time Scale Distributions (STSD), to characterize energy and interference of the observed data. The BAS will be allowed by joint diagonalization, without a prior orthogonality constraint, of a set of selected diagonal STSD matrices. Several criteria will be proposed, in the transformed time-scale space, to assess the separated audio signal contents. We describe the logistics of the separation and the content rating, thus an exemplary implementation on synthetic signals and real audio recordings show the high efficiency of the proposed technique to restore the audio signal contents.

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Hoskin, Philippa M., and Elizabeth A. New. "‘BY THE IMPRESSION OF MY SEAL’. MEDIEVAL IDENTITY AND BUREAUCRACY: A CASE STUDY." Antiquaries Journal 100 (September 16, 2019): 190–212. http://dx.doi.org/10.1017/s0003581519000015.

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This paper presents the results of a case study of wax seals dated between 1225 and 1250 from St Ethelbert’s Hospital, Hereford. When medieval matrices were impressed into soft wax, handprints were often left on the reverse of the seal. The use of modern forensic techniques to capture and compare these prints provides evidence about the process of sealing and its relationship to the individual matrix owner. Seals with the same print on the reverse could be impressed with different matrices, and impressions of the same matrix have different prints on the reverse. The impressing of the matrix was not, then, as has been claimed, the responsibility of the matrix owner as the only way to impress their identity into the wax. This evidence allows a reappraisal of administrative developments in sealing, and the separation of the process of sealing from both the performance of livery of seisin and the seal owner.

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Najarneghad, Behrouz, Abbas Asakereh, and Houshang Bahrami. "Strategic Analysis of Household Waste Separation at Source Using Swot Matrix, a Case Study: Ahvaz, Iran." Journal of Solid Waste Technology and Management 48, no. 3 (August 1, 2022): 432–42. http://dx.doi.org/10.5276/jswtm/2022.432.

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Анотація:

Separation of household waste at the source plays an important role in the sustainable management of MSW. In the present study, SWOT analysis, which is one of the strongest strategic planning techniques, was used to determine the effective factors and the most appropriate strategies for household waste separation in Ahvaz, Iran. Data were collected from 20 experts and 523 households using questionnaires. The overall priority scores of the internal and external factor evaluation matrices were 1.579 and 2.736, respectively, which indicates the unfavorable conditions of internal factors and relatively favorable conditions of external factors in the separation of household waste at the source. SWOT analysis showed that the competitive strategy is the most appropriate strategy for household waste separation at the source in Ahvaz, which is based on the maximum exploitation of opportunities with simultaneous reduction of weaknesses. The potential of energy saving as a result of recycling materials and electricity generation from municipal solid waste by anaerobic digestion process in Ahvaz was obtained at about 176 and 53 GWh/year, respectively. The results showed that SWOT analysis can be a promising method to determine the strengths, weaknesses, opportunities, and threats of separation of household waste at the source and provide the most appropriate strategy for their segregation.

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ROBERTSON, L. J., and B. GJERDE. "Factors Affecting Recovery Efficiency in Isolation of Cryptosporidium Oocysts and Giardia Cysts from Vegetables for Standard Method Development." Journal of Food Protection 64, no. 11 (November 1, 2001): 1799–805. http://dx.doi.org/10.4315/0362-028x-64.11.1799.

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While recently published techniques for recovering parasites from fruits and vegetables demonstrate a marked increase in efficiency and utility, there is still scope for further improvement in developing a standard method, particularly with difficult, but important, sample matrices such as bean sprouts. Herein, a number of parameters used in published techniques are investigated more closely. While sample size reduction may improve recovery efficiency because of a range of factors, it is important to keep the sample large enough for detection of low-level contamination. Age of sample is also important, and samples should be as fresh as possible. Elution procedures may contribute to losses of Giardia and should be more thoroughly investigated. Improved immunomagnetic separation techniques currently coming onto the market also have the potential to increase recovery efficiency substantially, even with difficult samples such as aged bean sprouts. However, merely increasing magnetic strength of the capturing magnet does not affect recovery efficiency, which must be reliant on a superior bead system, buffering system, or both.

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Cortese, Manuela, Maria Rosa Gigliobianco, Federico Magnoni, Roberta Censi, and Piera Di Martino. "Compensate for or Minimize Matrix Effects? Strategies for Overcoming Matrix Effects in Liquid Chromatography-Mass Spectrometry Technique: A Tutorial Review." Molecules 25, no. 13 (July 3, 2020): 3047. http://dx.doi.org/10.3390/molecules25133047.

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Анотація:

In recent decades, mass spectrometry techniques, particularly when combined with separation methods such as high-performance liquid chromatography, have become increasingly important in pharmaceutical, bio-analytical, environmental, and food science applications because they afford high selectivity and sensitivity. However, mass spectrometry has limitations due to the matrix effects (ME), which can be particularly marked in complex mixes, when the analyte co-elutes together with other molecules, altering analysis results quantitatively. This may be detrimental during method validation, negatively affecting reproducibility, linearity, selectivity, accuracy, and sensitivity. Starting from literature and own experience, this review intends to provide a simple guideline for selecting the best operative conditions to overcome matrix effects in LC-MS techniques, to obtain the best result in the shortest time. The proposed methodology can be of benefit in different sectors, such as pharmaceutical, bio-analytical, environmental, and food sciences. Depending on the required sensitivity, analysts may minimize or compensate for ME. When sensitivity is crucial, analysis must try to minimize ME by adjusting MS parameters, chromatographic conditions, or optimizing clean-up. On the contrary, to compensate for ME analysts should have recourse to calibration approaches depending on the availability of blank matrix. When blank matrices are available, calibration can occur through isotope labeled internal standards and matrix matched calibration standards; conversely, when blank matrices are not available, calibration can be performed through isotope labeled internal standards, background subtraction, or surrogate matrices. In any case, an adjusting of MS parameters, chromatographic conditions, or a clean-up are necessary.

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48

Kircher, Raphael, Sarah Mross, Hans Hasse, and Kerstin Münnemann. "Functionalized Controlled Porous Glasses for Producing Radical-Free Hyperpolarized Liquids by Overhauser DNP." Molecules 27, no. 19 (September 28, 2022): 6402. http://dx.doi.org/10.3390/molecules27196402.

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Overhauser dynamic nuclear polarization (ODNP) can be used as a tool for NMR signal enhancement and happens on very short time scales. Therefore, ODNP is well suited for the measurement of fast-flowing samples, even in compact magnets, which is beneficial for the real-time monitoring of chemical reactions or processes. ODNP requires the presence of unpaired electrons in the sample, which is usually accomplished by the addition of stable radicals. However, radicals affect the nuclear relaxation times and can hamper the NMR detection. This is circumvented by immobilizing radicals in a packed bed allowing for the measurement of radical-free samples when using ex situ DNP techniques (DNP build-up and NMR detection happen at different places) and flow-induced separation of the hyperpolarized liquid from the radicals. Therefore, the synthesis of robust and chemically inert immobilized radical matrices is mandatory. In the present work, this is accomplished by immobilizing the radical glycidyloxy-tetramethylpiperidinyloxyl with a polyethyleneimine (PEI) linker on the surface of controlled porous glasses (CPG). Both the porosity of the CPGs and also the size of the PEI-linker were varied, resulting in a set of distinct radical matrices for continuous-flow ODNP. The study shows that CPGs with PEI-linkers provide robust, inert and efficient ODNP matrices.

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49

Chen, Hongyun, Hongbo Zeng, and Huaming Yang. "Phosphate Removal from Wastewater by Magnetic Amorphous Lanthanum Silicate Alginate Hydrogel Beads." Minerals 12, no. 2 (January 29, 2022): 171. http://dx.doi.org/10.3390/min12020171.

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It is of both fundamental and practical importance to develop effective adsorbents for removing phosphate from aqueous solutions continuously. In this study, magnetic amorphous lanthanum silicate alginate hydrogel beads (MALS-B) were prepared and used for phosphate removal. Mesoporous silica materials with highly ordered and hexagonal channel structures were synthesized from natural mineral rectorite (REC) at room temperature. On this basis, amorphous lanthanum silicate (ALS) was synthesized by theone-pot method using a silicon source from REC and a commercial lanthanum source. Further, MALS-B were synthesized from sodium alginate (SA) with ALS and Fe3O4 as the incorporated adsorbable and magnetic nanoparticles via a simple cross-linking method in CaCl2 solution. The synthesized hydrogel beads were characterized by various techniques. ALS and Fe3O4 existed relatively independently in MALS-B, where ALS provided adsorption sites and Fe3O4 provided magnetism. They played a synergistic role in phosphate removal. The saturation magnetization value of MALS-B was 17.38 emu/g, enabling theirfacile separation from aqueous solutions after phosphate adsorption. MALS-B exhibited a preferable adsorption capacity of 40.14 mg P/g for phosphorus compared to other hydrogel beads based on adsorption experiments. More significantly, MALS-B exhibited excellent selectivity for phosphate in aqueous solutions with various interfering ions and possessed a high affinity to phosphate in a wide pH range. MALS-B showed the treatment volume of 480 BV when effluent phosphate concentration was below 0.5 mg/L in fixed-bed column adsorption. The adsorption mechanism was also revealed. Our work demonstrates that MALS-B can serve as a promising adsorbent for continuous phosphate adsorption.

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Michalski, Rajmund, Sebastian Szopa, Magdalena Jabłońska, and Aleksandra Łyko. "Application of Hyphenated Techniques in Speciation Analysis of Arsenic, Antimony, and Thallium." Scientific World Journal 2012 (2012): 1–17. http://dx.doi.org/10.1100/2012/902464.

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Due to the fact that metals and metalloids have a strong impact on the environment, the methods of their determination and speciation have received special attention in recent years. Arsenic, antimony, and thallium are important examples of such toxic elements. Their speciation is especially important in the environmental and biomedical fields because of their toxicity, bioavailability, and reactivity. Recently, speciation analytics has been playing a unique role in the studies of biogeochemical cycles of chemical compounds, determination of toxicity and ecotoxicity of selected elements, quality control of food products, control of medicines and pharmaceutical products, technological process control, research on the impact of technological installation on the environment, examination of occupational exposure, and clinical analysis. Conventional methods are usually labor intensive, time consuming, and susceptible to interferences. The hyphenated techniques, in which separation method is coupled with multidimensional detectors, have become useful alternatives. The main advantages of those techniques consist in extremely low detection and quantification limits, insignificant interference, influence as well as high precision and repeatability of the determinations. In view of their importance, the present work overviews and discusses different hyphenated techniques used for arsenic, antimony, and thallium species analysis, in different clinical, environmental and food matrices.

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