In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial ...uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na
2CO
3 and K
2SO
4. The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63
μmol/g and 667.40
μmol/g, respectively. The desorptive solutions of HCl, NaOH, Na
2CO
3, K
2SO
4, CaCO
3, humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1
M HCl.
A method for qualitative and quantitative the determination of concentrations volatile organic compounds (VOCs) in human breath samples using solid phase microextraction (SPME) and gas ...chromatography–time of flight–mass spectrometry (GC–TOF/MS) has been carried out. They are employed for the preconcentration, separation and analysis of biological samples. The technique to rapid determination compounds present in human air, at the level of parts per billion (ppb) is applied. This method was optimized and evaluated. It showed linear correlations ranging from 0.83 to 234.05
ppb, limit of detection in the range of 0.31 to 0.75
ppb and precision, expressed as the RSD, was less then 10.00%. The unique combination of statistical methods allowed reduce the number of compounds to significant ones only and indicate the potential way to find the biomarkers of the lung cancer. Presented an analytical and statistical methods for detection composition of exhaled air could be applied as a potential non-intrusive tool for screening of lung cancer.
Interactions of Whey Proteins with Metal Ions Rodzik, Agnieszka; Pomastowski, Paweł; Sagandykova, Gulyaim N ...
International journal of molecular sciences,
03/2020, Letnik:
21, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Whey proteins tend to interact with metal ions, which have implications in different fields related to human life quality. There are two impacts of such interactions: they can provide opportunities ...for applications in food and nutraceuticals, but may lead to analytical challenges related to their study and outcomes for food processing, storage, and food interactions. Moreover, interactions of whey proteins with metal ions are complicated, requiring deep understanding, leading to consequences, such as metalloproteins, metallocomplexes, nanoparticles, or aggregates, creating a biologically active system. To understand the phenomena of metal-protein interactions, it is important to develop analytical approaches combined with studies of changes in the biological activity and to analyze the impact of such interactions on different fields. The aim of this review was to discuss chemistry of β-lactoglobulin, α-lactalbumin, and lactotransferrin, their interactions with different metal ions, analytical techniques used to study them and the implications for food and nutraceuticals.
Amino acids and peptides (di- and tripeptides) as chemically bonded ligands in liquid chromatography were investigated. The comparison between 9 home-made amino acid- and peptide-silica stationary ...phases in hydrophilic interaction liquid chromatography (HILIC) and reversed-phase liquid chromatography (RP HPLC) systems has been presented. The investigated stationary phases were modified by the following amino acids: phenylalanine, leucine, alanine, glycine, and aspartic acid. Desired interactions were derived from the retention variation between pairs of similar solutes differing with particular structure properties. In the case of HILIC mode, the characterization was performed in terms of the degree of hydrophilicity, selectivity for hydrophilic–hydrophobic compounds, selectivity for the regio and configurational substituents, anion and cation exchange properties, and acidic or basic nature of the stationary phase surface. Under RP HPLC conditions, following features were elucidated: hydrophobicity, hydrophobic selectivity, shape selectivity, hydrogen bonding, electrostatic interactions at pH values 2.7 and 7.6. The results of the selectivity for partial structural differences were presented as radar-shaped plots and in tabular format. The factor analysis (FA) based on the principal component analysis (PCA) was also used in the stationary phase comparison. The performed research assisted in the evaluation of the relation between the chemical properties of bonded amino acid sequence and their role in the retention mechanism.
Flow cytometry is a sophisticated technology used widely in both basic research and as a routine tool in clinical diagnosis. The technology has progressed from single parameter detection in the 1970s ...and 1980s to high end multicolor analysis, with currently 30 parameters detected simultaneously, allowing the identification and purification of rare subpopulations of cells of interest. Flow cytometry continues to evolve and expand to facilitate the investigation of new diagnostic and therapeutic avenues. The present review gives an overview of basic theory and instrumentation, presents and compares the advantages and disadvantages of conventional, spectral and imaging flow cytometry as well as mass cytometry. Current methodologies and applications in both research, pre- and clinical settings are discussed, as well as potential limitations and future evolution. This finding encourages the reader to promote such relationship between basic science, diagnosis and multidisciplinary approach since the standard methods have limitations (e.g., in differentiating the cells after staining). Moreover, such path inspires future cytometry specialists develop new/alternative frontiers between pre- and clinical diagnosis and be more flexible in designing the study for both human as well as veterinary medicine.
In the presented work identification of microorganisms isolated from various types of honeys was performed. Martix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) ...and 16S rDNA sequencing were applied to study environmental bacteria strains.With both approches, problematic spore-forming Bacillus spp, but also Staphylococcus spp., Lysinibacillus spp., Micrococcus spp. and Brevibacillus spp were identified. However, application of spectrometric technique allows for an unambiguous distinction between species/species groups e.g.B. subtilis or B. cereus groups. MALDI TOF MS and 16S rDNA sequencing allow for construction of phyloproteomic and phylogenetic trees of identified bacterial species. Furthermore, the correlation beetween physicochemical properties, geographical and botanical origin and the presence bacterial species in honey samples were investigated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Background/Purpose In this study, an acidophilic actinobacteria strain was used as a novel reducing agent for a single-step synthesis of nanostructure silver particles. We used a ...Streptacidiphilus durhamensis HGG16n isolate for efficient synthesis of bioactive silver nanoparticles bio(AgNPs) in an inexpensive, eco-friendly, and nontoxic manner. The obtained bio(AgNPs) exhibited unique physicochemical and biochemical properties. Methods Structural, morphological, and optical properties of the synthesized biocolloids were characterized by spectroscopy, dynamic light scattering, and electron microscopy approaches. The antimicrobial activity was evaluated using the well- and disc-diffusion methods. Results The obtained crystalline structure and stable biosynthesized silver nanoparticles ranged in size from 8 nm to 48 nm and were mostly spherical in shape. Antimicrobial assays of the silver nanoparticles against pathogenic bacteria showed the highest antimicrobial activity against Pseudomonas aeruginosa , Staphylococcus aureus , and Proteus mirabilis, followed by Escherichia coli , Klebsiella pneumoniae , and Bacillus subtilis . Moreover, the synergistic effect of bio(AgNPs) with various commercially available antibiotics was also evaluated. Conclusion These results provide insight into the development of new antimicrobial agents along with synergistic enhancement of the antibacterial mechanism against clinical bacteria.
Reversed-phase high-performance liquid chromatography (RP-HPLC) is the most popular chromatographic mode, accounting for more than 90% of all separations. HPLC itself owes its immense popularity to ...it being relatively simple and inexpensive, with the equipment being reliable and easy to operate. Due to extensive automation, it can be run virtually unattended with multiple samples at various separation conditions, even by relatively low-skilled personnel. Currently, there are >600 RP-HPLC columns available to end users for purchase, some of which exhibit very large differences in selectivity and production quality. Often, two similar RP-HPLC columns are not equally suitable for the requisite separation, and to date, there is no universal RP-HPLC column covering a variety of analytes. This forces analytical laboratories to keep a multitude of diverse columns. Therefore, column selection is a crucial segment of RP-HPLC method development, especially since sample complexity is constantly increasing. Rationally choosing an appropriate column is complicated. In addition to the differences in the primary intermolecular interactions with analytes of the dispersive (London) type, individual columns can also exhibit a unique character owing to specific polar, hydrogen bond, and electron pair donor–acceptor interactions. They can also vary depending on the type of packing, amount and type of residual silanols, “end-capping”, bonding density of ligands, and pore size, among others. Consequently, the chromatographic performance of RP-HPLC systems is often considerably altered depending on the selected column. Although a wide spectrum of knowledge is available on this important subject, there is still a lack of a comprehensive review for an objective comparison and/or selection of chromatographic columns. We aim for this review to be a comprehensive, authoritative, critical, and easily readable monograph of the most relevant publications regarding column selection and characterization in RP-HPLC covering the past four decades. Future perspectives, which involve the integration of state-of-the-art molecular simulations (molecular dynamics or Monte Carlo) with minimal experiments, aimed at nearly “experiment-free” column selection methodology, are proposed.
Oligonucleotides have many important applications, including as primers in polymerase chain reactions and probes for DNA sequencing. They are proposed as a diagnostic and prognostic tool for various ...diseases and therapeutics in antisense therapy. Accordingly, it is necessary to develop liquid chromatography and solid phase extraction methods to separate oligonucleotides and isolate them from biological samples. Many reviews have been written about the determination of these compounds using the separation technique or sample preparation for their isolation. However, presumably, there are no articles that critically review the adsorbents used in liquid chromatography or solid phase extraction. The present publication reviews the literature from the last twenty years related to supports (silica, polymers, magnetic nanoparticles) and their modifications. The discussed issues concern reversed phase (alkyl, aromatic, cholesterol, mixed ligands), ion-exchange (strong and weak ones), polar (silica, polyhydroxy, amide, zwitterionic), and oligonucleotide-based adsorbents.
This paper describes the most significant achievements related to the creation and development of separation methods. Tswiett Nerst’s achievements and the role of such centers as Lublin, Warsaw, ...Gdańsk, Poznań, Łódź, Silesia, Kraków and Toruń are presented, as well as the role of leaders who created theories and methodological studies on chromatography and related techniques. The role of sample preparation methods is emphasized based on the same or similar theoretical foundations. The directions of developing these techniques in Poland today and in the future are presented.
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