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Analytical chemistry

Camila Tavares Rebouças, Ana Carolina Kogawa, Hérida Regina Nunes Salgado
Background: A green analytical chemistry method was developed for quantification of enrofloxacin in tablets. The drug, a second-generation fluoroquinolone, was first introduced in veterinary medicine for the treatment of various bacterial species. Objective: This study proposed to develop, validate, and apply a reliable, low-cost, fast, and simple IR spectroscopy method for quantitative routine determination of enrofloxacin in tablets. Methods: The method was completely validated according to the International Conference on Harmonisation guidelines, showing accuracy, precision, selectivity, robustness, and linearity...
May 18, 2018: Journal of AOAC International
Miriana Kfoury, David Landy, Sophie Fourmentin
Cyclodextrins (CDs) are a family of cyclic oligosaccharides that constitute one of the most widely used molecular hosts in supramolecular chemistry. Encapsulation in the hydrophobic cavity of CDs positively affects the physical and chemical characteristics of the guests upon the formation of inclusion complexes. Such a property is interestingly employed to retain volatile guests and reduce their volatility. Within this scope, the starting crucial point for a suitable and careful characterization of an inclusion complex is to assess the value of the formation constant (Kf ), also called stability or binding constant...
May 17, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Jared L Anderson, Kevin D Clark
No abstract text is available yet for this article.
May 17, 2018: Analytical and Bioanalytical Chemistry
Ruiter L Morais, Mariângela F Santiago, Joachim W Zang, Warde A Fonseca-Zang, Fernando Schimidt
One of the most prominent fields of environmental chemistry is the study and the removal of micro-pollutants from aqueous matrices. Analytical techniques for their identification and quantification are becoming more sensitive and comprehensive and, as a result, an increasing number of drugs have been detected in environmental samples. However, the literature shows that conventional treatments for drinking water and wastewater are not sufficient for remove these compounds. This study aims to check whether the process of hydrothermal carbonization (CHT) is effective in removing the synthetic sex hormones: ethinyl estradiol, gestodene and cyproterone acetate from aqueous samples...
May 14, 2018: Anais da Academia Brasileira de Ciências
Jie Sun, Huihui Liu, Lingpeng Zhan, Caiqiao Xiong, Xi Huang, Jinjuan Xue, Zongxiu Nie
Cell-surface sialoglycoconjugates (sialoglycoproteins & sialoglycolipids) play important roles in cell-cell interactions and related tumor metastasis process. Although there have been some analytical methods to evaluate the sialoglycoconjugates, an effective method providing both qualitative and quantitative information is still deficient. Here we establish an extraction-free, sensitive and high-throughput platform to realize in-situ detection of the cell-surface sialoglycoconjugates on various cell lines, e...
May 16, 2018: Analytical Chemistry
Wolfgang Vautz, Chandrasekhara Hariharan, Maximilian Weigend
Plant volatile organic compounds (pVOCs) are being recognized as an important factor in plant-environment interactions. Both the type and amount of the emissions appear to be heavily affected by climate change. A range of studies therefore has been directed toward understanding pVOC emissions, mostly under laboratory conditions (branch/leaf enclosure). However, there is a lack of rapid, sensitive, and selective analytical methods, and therefore, only little is known about VOC emissions under natural, outdoor conditions...
May 2018: Ecology and Evolution
Michel R Langlois, M John Chapman, Christa Cobbaert, Samia Mora, Alan T Remaley, Emilio Ros, Gerald F Watts, Jan Borén, Hannsjörg Baum, Eric Bruckert, Alberico Catapano, Olivier S Descamps, Arnold von Eckardstein, Pia R Kamstrup, Genovefa Kolovou, Florian Kronenberg, Anne Langsted, Kari Pulkki, Nader Rifai, Grazyna Sypniewska, Olov Wiklund, B Rge G Nordestgaard
BACKGROUND: The European Atherosclerosis Society-European Federation of Clinical Chemistry and Laboratory Medicine Consensus Panel aims to provide recommendations to optimize atherogenic lipoprotein quantification for cardiovascular risk management. CONTENT: We critically examined LDL cholesterol, non-HDL cholesterol, apolipoprotein B (apoB), and LDL particle number assays based on key criteria for medical application of biomarkers. ( a ) Analytical performance: Discordant LDL cholesterol quantification occurs when LDL cholesterol is measured or calculated with different assays, especially in patients with hypertriglyceridemia >175 mg/dL (2 mmol/L) and low LDL cholesterol concentrations <70 mg/dL (1...
May 14, 2018: Clinical Chemistry
Shao-Hua Guo, Tao-Hua Leng, Kai Wang, Cheng-Yun Wang, Yong-Jia Shen, Wei-Hong Zhu
Developing fluorescent probes for specific detection of extremely toxic thiophenols is pretty significant in the field of environment, chemistry and biology. We report herein a turn-on red fluorescent xanthene-based probe (RD-Probe) for detecting thiophenol with high selectivity over other analytes including aliphatic thiols. The probe could play the part of a "naked-eye"colorimetric indicator toward thiophenol. Moreover, the relative fluorescence intensity at 653 nm displayed good linearity with the concentration of thiophenol ranging from 0 to 6 μM, and the limit of detection for thiophenol could be as low as 15 nM...
August 1, 2018: Talanta
Dmitry N Makarov
A system of two coupled quantum harmonic oscillators with the Hamiltonian H[over ̂]=1/2(1/m_{1}p[over ̂]_{1}^{2}+1/m_{2}p[over ̂]_{2}^{2}+Ax_{1}^{2}+Bx_{2}^{2}+Cx_{1}x_{2}) can be found in many applications of quantum and nonlinear physics, molecular chemistry, and biophysics. The stationary wave function of such a system is known, but its use for the analysis of quantum entanglement is complicated because of the complexity of computing the Schmidt modes. Moreover, there is no exact analytical solution to the nonstationary Schrodinger equation H[over ̂]Ψ=iℏ∂Ψ/∂t and Schmidt modes for such a dynamic system...
April 2018: Physical Review. E
Tiago Monteiro, Maria Gabriela Almeida
Worldwide legislation is driving the development of novel and highly efficient analytical tools for assessing the composition of every material that interacts with Consumers or Nature. The biosensor technology is one of the most active R&D domains of Analytical Sciences focused on the challenge of taking analytical chemistry to the field. Electrochemical biosensors based on redox enzymes, in particular, are highly appealing due to their usual quick response, high selectivity and sensitivity, low cost and portable dimensions...
May 14, 2018: Critical Reviews in Analytical Chemistry
Sara Tengattini, Francesca Rinaldi, Luciano Piubelli, Tom Kupfer, Benjamin Peters, Teodora Bavaro, Enrica Calleri, Gabriella Massolini, Caterina Temporini
One of the most popular enzymes used for the in vitro cleavage of fusion proteins is enterokinase (EK, E.C. EK cleaves with high specificity after the sequence Asp4 -Lys (DDDDK), which allows the fusion protein to preserve its native amino acid terminus without any additional unwanted cleavage residue from the recognition sequence. However, the complete removal of EK after protein cleavage is a critical step to ensure protein identity and stability. As enzyme immobilization increases stability and reusability of the biocatalyst while reducing operating costs and sample contamination, in this work we report the covalent immobilization of recombinant EK (rEK) on monolithic chromatographic supports with different binding chemistries for the development of a rEK-chromatographic-bioreactor...
May 4, 2018: Journal of Pharmaceutical and Biomedical Analysis
M Scalabrin, S M Dixit, M M Makshood, C E Krzemien, Daniele Fabris
With the goal of expanding the very limited toolkit of cross-linking agents available for nucleic acids and their protein complexes, we evaluated the merits of a wide range of bifunctional agents that may be capable of reacting with the functional groups characteristic of these types of biopolymers. The survey specifically focused on the ability of test reagents to produce desirable inter-molecular conjugates, which could reveal the identity of interacting components and the position of mutual contacts, while also considering a series of practical criteria for their utilization as viable nucleic acid probes...
May 9, 2018: Methods: a Companion to Methods in Enzymology
Ruiqiang Hang, Yanlian Liu, Long Bai, Xiangyu Zhang, Xiaobo Huang, Husheng Jia, Bin Tang
In the present work, nickel-titanium-oxygen nanopores with different length (0.55-114 μm) were anodically grown on nearly equiatomic nickel-titanium (NiTi) alloy. Length-dependent corrosion behavior, nickel ion (Ni2+ ) release, cytocompatibility, and antibacterial ability were investigated by electrochemical, analytical chemistry, and biological methods. The results show constructing nanoporous structure on the NiTi alloy improve its corrosion resistance. However, the anodized samples release more Ni2+ than that of the bare NiTi alloy, suggesting chemical dissolution of the nanopores rather than electrochemical corrosion governs the Ni2+ release...
August 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Angela-Nadia Albetel, Caryn E Outten
Monothiol glutaredoxins (Grxs) with a conserved Cys-Gly-Phe-Ser (CGFS) active site are iron-sulfur (Fe-S) cluster-binding proteins that interact with a variety of partner proteins and perform crucial roles in iron metabolism including Fe-S cluster transfer, Fe-S cluster repair, and iron signaling. Various analytical and spectroscopic methods are currently being used to monitor and characterize glutaredoxin Fe-S cluster-dependent interactions at the molecular level. The electronic, magnetic, and vibrational properties of the protein-bound Fe-S cluster provide a convenient handle to probe the structure, function, and coordination chemistry of Grx complexes...
2018: Methods in Enzymology
Michael Z Kamrath, Thomas R Rizzo
Ion mobility spectrometry (IMS) has become a valuable tool in biophysical and bioanalytical chemistry because of its ability to separate and characterize the structure of gas-phase biomolecular ions on the basis of their collisional cross section (CCS). Its importance has grown with the realization that in many cases, biomolecular ions retain important structural characteristics when produced in the gas phase by electrospray ionization (ESI). While a CCS can help distinguish between structures of radically different types, one cannot expect a single number to differentiate similar conformations of a complex molecule...
May 10, 2018: Accounts of Chemical Research
Hiroshi Yukawa, Yoshinobu Baba
Quantum dots (QDs) have excellent fluorescence properties in comparison to traditional fluorescence probes. Thus, the optical application of QDs is rapidly expanding to each field of analytical chemistry. In this review paper, we reviewed the application of QDs to regenerative medicine, especially stem cell transplantation therapy. The labeling of stem cells using QDs composed of semiconductor materials in combination with a chemical substance, poly-cationic liposome and cell penetrating peptide is reported...
2018: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Darci R Block, Lucas J Ouverson, Craig A Wittwer, Amy K Saenger, Nikola A Baumann
BACKGROUND: Biochemical analysis of body fluids may lend insight into the pathogenesis of disease. Most commercially-available clinical laboratory methods are intended for blood-derived specimens and/or urine and laboratories must characterize the analytical performance of these methods for other specimen types such as body fluids. The aim of this work is to demonstrate one approach for characterizing analytical performance of assays for clinical analysis of body fluids. METHODS: Residual waste samples were obtained from clinically ordered testing...
May 5, 2018: Clinical Biochemistry
Tatiana Shekhovtsova
No abstract text is available yet for this article.
May 8, 2018: Analytical and Bioanalytical Chemistry
Hossam Al-Suod, Paweł Pomastowski, Magdalena Ligor, Viorica Railean-Plugaru, Bogusław Buszewski
INTRODUCTION: Alfalfa (Medicago sativa L.) is the subject of many studies due to its numerous chemical constituents and beneficial properties. Among these constituents are cyclitols, which have attracted attention due to the variety of biological properties they have. OBJECTIVE: A rapid and sensitive analytical procedure based on matrix-assisted laser desorption ionisation technique with time-of-flight and mass spectrometry (MALDI-TOF-MS) analysis was used for the first time for the identification of three cyclitols from different parts of alfalfa...
May 6, 2018: Phytochemical Analysis: PCA
Hannah M Pezzi, David J Niles, Jennifer L Schehr, David J Beebe, Joshua M Lang
Magnetic bead-based analyte capture has emerged as a ubiquitous method in cell isolation, enabling the highly specific capture of target populations through simple magnetic manipulation. To date, no "one-size fits all" magnetic bead has been widely adopted leading to an overwhelming number of commercial beads. Ultimately, the ideal bead is one that not only facilitates cell isolation but also proves compatible with the widest range of downstream applications and analytic endpoints. Despite the diverse offering of sizes, coatings, and conjugation chemistries, few studies exist to benchmark the performance characteristics of different commercially available beads; importantly, these bead characteristics ultimately determine the ability of a bead to integrate into the user's assay...
April 30, 2018: ACS Omega
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