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Analytical chemistry

Betina Klint Nielsen, Tina Frederiksen, Lennart Friis-Hansen, Pia Bükmann Larsen
BACKGROUND: Storage of blood samples after centrifugation, decapping and initial sampling allows ordering of additional blood tests. The pre-analytic stability of biochemistry and immunochemistry analytes has been studied in detail, but little is known about the post-analytical stability in incurred samples. METHODS: We examined the stability of 23 routine analytes on the Dimension Vista® (Siemens Healthineers, Denmark): 42-60 routine samples in lithium-heparin gel tubes (Vacutainer, BD, USA) were centrifuged at 3000×g for 10min...
August 10, 2017: Clinical Biochemistry
Alison R Turnbull, Jessica Y C Tan, Sarah C Ugalde, Gustaaf M Hallegraeff, Katrina Campbell, D Tim Harwood, Juan José Dorantes-Aranda
Detection of paralytic shellfish toxins (PSTs) in bivalve shellfish by analytical methods is complicated and costly, requiring specific expertise and equipment. Following extensive blooms of Alexandrium tamarense Group 1 in Tasmania, Australia, an investigation was made into commercially available screening test kits suitable for use with the toxin profiles found in affected bivalves. The qualitative Neogen rapid test kit, with a modified protocol to convert gonyautoxins GTX1&4 and GTX2&3 into neosaxitoxin and saxitoxin (STX), respectively, with higher cross-reactivities, was the best fit-for-purpose...
August 10, 2017: Journal of AOAC International
(no author information available yet)
No abstract text is available yet for this article.
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Frederico G DE Araujo, Glauco F Bauerfeldt, Yara Peluso Cid
This paper aims to gather and discuss important information about nonylphenol, such as physical chemistry properties, toxicity and analytical methods in various matrices. As a degradation product of ethoxylated alkylphenols, nonylphenol presents a higher degree of reactivity than its precursor. Due to its harmful effects on the environment, use and production of nonylphenol has been banned in European Union countries, alongside their precursors. The guide on quality of drinking water (USEPA) recommends a maximum concentration of 28 µg L-1 for fresh water...
August 7, 2017: Anais da Academia Brasileira de Ciências
Jae-Ho Kim, Jeong-Eun Park, Mouhong Lin, Sungi Kim, Gyeong-Hwan Kim, SungJun Park, GwangPyo Ko, Jwa-Min Nam
One of the most heavily used methods in chemical and biological labeling, detection, and imaging is based on silver shell-based enhancement on Au nanoparticles (AuNPs) that is useful for amplifying Rayleigh scattering, colorimetric signal, surface-enhanced Raman scattering, and electrical signal, but poor structural controllability and nonspecific growth of silver shells have limited its applications, especially with respect to signal reproducibility and quantification. Here, a highly specific, well-defined Cu nanopolyhedral shell overgrowth chemistry is developed with the aid of polyethyleneimine (PEI) on AuNPs, and the use of this PEI-mediated Cu polyhedral nanoshell (CuP) chemistry is shown as a means of light-scattering signal enhancement for the development of naked-eye-based highly sensitive and quantitative detections of DNA and viruses...
August 7, 2017: Advanced Materials
Andreas Herrmann
Profragrances or properfumes are important delivery systems for the controlled release of volatile compounds. They constitute an essential part of a series of commercial body care and household products to ensure the long-lastingness of perfume perception in practical application. Fragrances are released from their respective precursors by covalent bond cleavage under mild environmental conditions. Originating from organic chemistry, modern profragrance research has evolved to a truly interdisciplinary research area covering supramolecular science, physical chemistry, analytical chemistry and various aspects of materials science...
August 9, 2017: Chimia
Richard G Brereton, Jeroen Jansen, João Lopes, Federico Marini, Alexey Pomerantsev, Oxana Rodionova, Jean Michel Roger, Beata Walczak, Romà Tauler
Chemometrics has achieved major recognition and progress in the analytical chemistry field. In the first part of this tutorial, major achievements and contributions of chemometrics to some of the more important stages of the analytical process, like experimental design, sampling, and data analysis (including data pretreatment and fusion), are summarised. The tutorial is intended to give a general updated overview of the chemometrics field to further contribute to its dissemination and promotion in analytical chemistry...
August 3, 2017: Analytical and Bioanalytical Chemistry
Liqun Wang, Roberto Bravo Cardenas, Clifford Watson
CDC's Division of Laboratory Sciences developed and validated a new method for the simultaneous detection and measurement of 11 sugars, alditols and humectants in tobacco products. The method uses isotope dilution ultra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) and has demonstrated high sensitivity, selectivity, throughput and accuracy, with recoveries ranging from 90% to 113%, limits of detection ranging from 0.0002 to 0.0045μg/mL and coefficients of variation (CV%) ranging from 1...
July 26, 2017: Journal of Chromatography. A
Elizabeth D Wagner, Michael J Plewa
The disinfection of drinking water is an important public health service that generates high quality, safe and palatable tap water. The disinfection of drinking water to reduce waterborne disease was an outstanding public health achievement of the 20th century. An unintended consequence is the reaction of disinfectants with natural organic matter, anthropogenic contaminants and bromide/iodide to form disinfection by-products (DBPs). A large number of DBPs are cytotoxic, neurotoxic, mutagenic, genotoxic, carcinogenic and teratogenic...
August 2017: Journal of Environmental Sciences (China)
Rupashree Dass, Katarzyna Grudzia Ż, Takao Ishikawa, Michał Nowakowski, Renata Dȩbowska, Krzysztof Kazimierczuk
The biological toolbox is full of techniques developed originally for analytical chemistry. Among them, spectroscopic experiments are very important source of atomic-level structural information. Nuclear magnetic resonance (NMR) spectroscopy, although very advanced in chemical and biophysical applications, has been used in microbiology only in a limited manner. So far, mostly one-dimensional (1)H experiments have been reported in studies of bacterial metabolism monitored in situ. However, low spectral resolution and limited information on molecular topology limits the usability of these methods...
2017: Frontiers in Microbiology
Arjun Chennu, Paul Färber, Glenn De'ath, Dirk de Beer, Katharina E Fabricius
We developed a novel integrated technology for diver-operated surveying of shallow marine ecosystems. The HyperDiver system captures rich multifaceted data in each transect: hyperspectral and color imagery, topographic profiles, incident irradiance and water chemistry at a rate of 15-30 m(2) per minute. From surveys in a coral reef following standard diver protocols, we show how the rich optical detail can be leveraged to generate photopigment abundance and benthic composition maps. We applied machine learning techniques, with a minor annotation effort (<2% of pixels), to automatically generate cm-scale benthic habitat maps of high taxonomic resolution and accuracy (93-97%)...
August 2, 2017: Scientific Reports
Marshall L Timmermans, Yagya P Paudel, Avena C Ross
The phylum proteobacteria contains a wide array of Gram-negative marine bacteria. With recent advances in genomic sequencing, genome analysis, and analytical chemistry techniques, a whole host of information is being revealed about the primary and secondary metabolism of marine proteobacteria. This has led to the discovery of a growing number of medically relevant natural products, including novel leads for the treatment of multidrug-resistant Staphylococcus aureus (MRSA) and cancer. Of equal interest, marine proteobacteria produce natural products whose structure and biosynthetic mechanisms differ from those of their terrestrial and actinobacterial counterparts...
August 1, 2017: Marine Drugs
Adam B Taylor, Peter Zijlstra
Single-molecule detection has long relied on fluorescent labeling with high quantum-yield fluorophores. Plasmon-enhanced detection circumvents the need for labeling by allowing direct optical detection of weakly emitting and completely nonfluorescent species. This review focuses on recent advances in single molecule detection using plasmonic metal nanostructures as a sensing platform, particularly using a single particle-single molecule approach. In the past decade two mechanisms for plasmon-enhanced single-molecule detection have been demonstrated: (1) by plasmonically enhancing the emission of weakly fluorescent biomolecules, or (2) by monitoring shifts of the plasmon resonance induced by single-molecule interactions...
August 8, 2017: ACS Sensors
Francisco Calderón-Celis, Jorge Ruiz Encinar, Alfredo Sanz-Medel
Mass spectrometry-based approaches have enabled important breakthroughs in quantitative proteomics in the last decades. This development is reflected in the better quantitative assessment of protein levels as well as to understand post-translational modifications and protein complexes and networks. Nowadays, the focus of quantitative proteomics shifted from the relative determination of proteins (ie, differential expression between two or more cellular states) to absolute quantity determination, required for a more-thorough characterization of biological models and comprehension of the proteome dynamism, as well as for the search and validation of novel protein biomarkers...
July 31, 2017: Mass Spectrometry Reviews
Xiang-Long Meng, Jun-Nan Ma, Xiao-Hui Guo, Bing-Chen Liu, Nan-Nan Cui, Kun Li, Shuo-Sheng Zhang
OBJECTIVE: To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction (HLD, ) and San Huang Decoction (SHD, ). METHODS: Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures...
July 28, 2017: Chinese Journal of Integrative Medicine
Hardy Z Castada, Sheryl Barringer, Macdonald Wick
RATIONALE: 4-methyloctanoic acid, 4-ethyloctanoic acid, 4-methylnonanoic acid, and 3-methylindole are primary contributors to the distinctive aroma and flavor of lamb meat. The reactions of H3 O(+) , NO(+) , and O2(+) with these compounds, and identification of the product ions and their distribution, are fundamental to their characterization and rapid, real-time trace analysis using SIFT-MS. METHODS: The chemical ionization of pure standards of 4-ethyloctanoic acid, 4-methyloctanoic acid, 4-ethylnonanoic acid, and 3-methylindole was carried out using the H3 O(+) , NO(+) , and O2(+) reagent ions of a V200(TM) selected ion flow tube-mass spectrometer...
July 28, 2017: Rapid Communications in Mass Spectrometry: RCM
Gerald Steiner
No abstract text is available yet for this article.
July 27, 2017: Analytical and Bioanalytical Chemistry
Wenzhi Yang, Yibei Zhang, Wanying Wu, Luqi Huang, Dean Guo, Changxiao Liu
Traditional Chinese medicine (TCM) has played a pivotal role in maintaining the health of Chinese people and is now gaining increasing acceptance around the global scope. However, TCM is confronting more and more concerns with respect to its quality. The intrinsic "multicomponent and multitarget" feature of TCM necessitates the establishment of a unique quality and bioactivity evaluation system, which is different from that of the Western medicine. However, TCM is investigated essentially as "herbal medicine" or "natural product", and the pharmacopoeia quality monographs are actually chemical-markers-based, which can ensure the consistency only in the assigned chemical markers, but, to some extent, have deviated from the basic TCM theory...
July 2017: Acta Pharmaceutica Sinica. B
David R Janero, Anisha Korde, Alexandros Makriyannis
Detailed characterization of the ligand-binding motifs and structure-function correlates of the principal GPCRs of the endocannabinoid-signaling system, the cannabinoid 1 (CB1R) and cannabinoid 2 (CB2R) receptors, is essential to inform the rational design of drugs that modulate CB1R- and CB2R-dependent biosignaling for therapeutic gain. We discuss herein an experimental paradigm termed "ligand-assisted protein structure" (LAPS) that affords a means of characterizing, at the amino acid level, CB1R and CB2R structural features key to ligand engagement and receptor-dependent information transmission...
2017: Methods in Enzymology
Wei Xu, Kaiyu Fu, Paul W Bohn
Biosensors based on converting electrochemical signals into optical readouts are attractive candidates as low-cost, high-throughput sensor platforms. Here, we described a closed bipolar electrode (CBE)-based two-cell electrochromic device for sensing multiple metabolites, using the simultaneous detection of lactate, glucose, and uric acid as a model system. In the two-cell configuration, an analytical cell contains a redox mediator combined with a specific oxidase, e.g., lactate oxidase, glucose oxidase, or uricase, to form an electrochemical mediator-electrocatalyst pair that supports redox cycling...
July 28, 2017: ACS Sensors
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