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Analytical chemistry

Margaret E Hunter, Robert M Dorazio, John S S Butterfield, Gaia Meigs-Friend, Leo G Nico, Jason A Ferrante
A set of universal guidelines is needed to determine the limit of detection (LOD) in PCR-based analyses of low concentration DNA. In particular, environmental DNA (eDNA) studies require sensitive and reliable methods to detect rare and cryptic species through shed genetic material in environmental samples. Current strategies for assessing detection limits of eDNA are either too stringent or subjective, possibly resulting in biased estimates of species' presence. Here, a conservative LOD analysis grounded in analytical chemistry is proposed to correct for overestimated DNA concentrations predominantly caused by the concentration plateau, a nonlinear relationship between expected and measured DNA concentrations...
October 21, 2016: Molecular Ecology Resources
Rose Matilainen, Anniina Koliseva, Piia Valto, Jouni Välisaari
No abstract text is available yet for this article.
October 19, 2016: Analytical and Bioanalytical Chemistry
David A Selck, Rustem F Ismagilov
Nucleic acid amplification tests that are coupled with a digital readout enable the absolute quantification of single molecules, even at ultralow concentrations. Digital methods are robust, versatile and compatible with many amplification chemistries including isothermal amplification, making them particularly invaluable to assays that require sensitive detection, such as the quantification of viral load in occult infections or detection of sparse amounts of DNA from forensic samples. A number of microfluidic platforms are being developed for carrying out digital amplification...
2016: PloS One
Nouf Al Saleem, Khaled Al-Surimi
Frequent, preventable medical errors can have an adverse effect on patient safety and quality as well as leading to wasted resources. In the laboratory, errors can occur at any stage of sample processing; pre-analytical, analytical, and post analytical stages. However evidence shows most of the laboratory errors occur during the pre-analytical stage. The receipt and processing of specimens is one of the main steps in the pre-analytical stage. Errors in this stage could be due to mislabeling, incorrect test entry and entering the wrong location, among other reasons...
2016: BMJ Quality Improvement Reports
Félix Hernández, Sara Castiglioni, Adrian Covaci, Pim de Voogt, Erik Emke, Barbara Kasprzyk-Hordern, Christoph Ort, Malcolm Reid, Juan V Sancho, Kevin V Thomas, Alexander L N van Nuijs, Ettore Zuccato, Lubertus Bijlsma
The analysis of illicit drugs in urban wastewater is the basis of wastewater-based epidemiology (WBE), and has received much scientific attention because the concentrations measured can be used as a new non-intrusive tool to provide evidence-based and real-time estimates of community-wide drug consumption. Moreover, WBE allows monitoring patterns and spatial and temporal trends of drug use. Although information and expertise from other disciplines is required to refine and effectively apply WBE, analytical chemistry is the fundamental driver in this field...
October 17, 2016: Mass Spectrometry Reviews
Joseph Henny, Anne Vassault, Guilaine Boursier, Ines Vukasovic, Pika Mesko Brguljan, Maria Lohmander, Irina Ghita, Francisco A Bernabeu Andreu, Christos Kroupis, Ludek Sprongl, Marc H M Thelen, Florent J L A Vanstapel, Tatjana Vodnik, Willem Huisman, Michel Vaubourdolle
This document is based on the original recommendation of the Expert Panel on the Theory of Reference Values of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), updated guidelines were recently published under the auspices of the IFCC and the Clinical and Laboratory Standards Institute (CLSI). This document summarizes proposals for recommendations on: (i) The terminology, which is often confusing, noticeably concerning the terms of reference limits and decision limits. (ii) The method for the determination of reference limits according to the original procedure and the conditions, which should be used...
October 14, 2016: Clinical Chemistry and Laboratory Medicine: CCLM
Sascha Nehr, Elisabeth Hösen, Shin-Ichi Tanabe
Despite the fact that the special characteristics of indoor air pollution make closed environments quite different from outdoor environments, the conceptual ideas for assessing air quality indoors and outdoors are similar. Therefore, the elaboration of International Standards for air quality characterization in view of controlling indoor air quality should resort to this common basis. In this short review we describe the possibilities of standardization of tools dedicated to indoor air quality characterization with a focus on the tools permitting to study the indoor air chemistry...
October 11, 2016: Environment International
Erin Jo Tiedeken, Alexandre Tahar, Brendan McHugh, Neil J Rowan
Pollution of European receiving waters with contaminants of emerging concern (CECs), such as with 17-beta-estradiol (a natural estrogenic hormone, E2), along with pharmaceutically-active compounds diclofenac (an anti-inflammatory drug, DCL) and 17-alpha-ethynylestradiol (a synthetic estrogenic hormone, EE2)) is a ubiquitous phenomenon. These three CECs were added to the EU watch list of emerging substances to be monitoring in 2013, which was updated in 2015 to comprise 10 substances/groups of substances in the field of water policy...
October 11, 2016: Science of the Total Environment
Ximena Fadic, Fabián Placencia, Ana María Domínguez, Francisco Cereceda-Balic
There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays...
October 10, 2016: Science of the Total Environment
Smita S Kale, Krishnacharya G Akamanchi
Protein aggregation is a major problem of therapeutic proteins because aggregation decreases their therapeutic activity, shelf life and induces immunogenicity. Stabilization against aggregation is commonly attained by addition of different excipients like sugars, surfactants, buffers, salts, amino acids, polymers etc. Generally these excipients are required in combination for stabilization. Sugars are required at a higher concentration and commonly used surfactants like polysorbates have shortcomings due to oxidative degradation...
October 11, 2016: Molecular Pharmaceutics
G P Danezis, C J Anagnostopoulos, K Liapis, M A Koupparis
One of the recent trends in Analytical Chemistry is the development of economic, quick and easy hyphenated methods to be used in a field that includes analytes of different classes and physicochemical properties. In this work a multi-residue method was developed for the simultaneous determination of 28 xenobiotics (polar and hydrophilic) using hydrophilic interaction liquid chromatography technique (HILIC) coupled with triple quadrupole mass spectrometry (LC-MS/MS) technology. The scope of the method includes plant growth regulators (chlormequat, daminozide, diquat, maleic hydrazide, mepiquat, paraquat), pesticides (cyromazine, the metabolite of the fungicide propineb PTU (propylenethiourea), amitrole), various multiclass antibiotics (tetracyclines, sulfonamides quinolones, kasugamycin and mycotoxins (aflatoxin B1, B2, fumonisin B1 and ochratoxin A)...
October 26, 2016: Analytica Chimica Acta
Ilenia Infusino, Erika Frusciante, Federica Braga, Mauro Panteghini
International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has established reference measurement procedures (RMPs) for the most popular enzymes. Manufacturers should assign values to commercial calibrators traceable to these RMPs to achieve equivalent results in clinical samples, independent of reagent kits, instruments, and laboratory where the measurement is carried out. The situation is, however, far from acceptable. Some manufacturers continue to market assays giving results that are not traceable to internationally accepted RMPs...
October 8, 2016: Clinical Chemistry and Laboratory Medicine: CCLM
Ramón González-Méndez, Peter Watts, David Olivenza-León, D Fraser Reich, Stephen J Mullock, Clive A Corlett, Stuart Cairns, Peter Hickey, Matthew Brookes, Chris Anthony Mayhew
A key issue with any analytical system based on mass spectrometry with no initial separation of compounds is to have a high level of confidence in assignment. This is particularly true for areas of security, such as airports, and recent terrorist attacks have highlighted the need for reliable analytical instrumentation. Proton transfer reaction mass spectrometry is a useful technology for these purposes because the chances of false positives are small owing to the use of a mass spectrometric analysis. However, the detection of an ion at a given m/z for an explosive does not guarantee that that explosive is present...
October 7, 2016: Analytical Chemistry
Danijela Gregurec, Susana Velasco-Lozano, Sergio E Moya, Luis Vázquez, Fernando López-Gallego
Optimal immobilization of enzymes on porous microbeads enables the fabrication of highly active and stable heterogeneous biocatalysts to implement biocatalysis in synthetic and analytical chemistry. However, empirical procedures for enzyme immobilization still prevail over rational ones because there is an unmet need for more comprehensive characterization techniques that aid to understand and trace the immobilization process. Here, we present the use of atomic force spectroscopy (AFS) as an innovative solution to indirectly characterize immobilized proteins on porous materials and monitor the immobilization process in real time...
October 6, 2016: Soft Matter
Katy O Goyak, Ming H Kung, Min Chen, Keith K Aldous, James J Freeman
Residual aromatic extracts (RAE) are petroleum substances with variable composition predominantly containing aromatic hydrocarbons with carbon numbers greater than C25. Because of the high boiling nature of RAEs, the aromatics present are high molecular weight, with most above the range of carcinogenic polycyclic aromatic hydrocarbons (PAHs). However, refinery distillations are imperfect; some PAHs and their heteroatom-containing analogs (collectively referred to as polycyclic aromatic content or PAC) may remain in the parent stream and be extracted into the RAE, and overall PAC content is related to the carcinogenic potential of an RAE...
October 3, 2016: Toxicology Letters
Wenfen Zhang, Yanhao Zhang, Qiong Jiang, Wenjie Zhao, Ajuan Yu, Hong Chang, Ximei Lu, Fuwei Xie, Baoxian Ye, Shusheng Zhang
To satisfy the requirement of simultaneous extraction and characterization of diverse kinds of multi-target analytes, the preparation, characterization and application of a novel tetraazacalix[2]arene[2]triazine (TCT) coated magnetic nanoparticular (TCT MNP) adsorbent are presented in this paper. TCT assembles two benzene rings and two triazines with nitrogen cross-bridging links, which exhibits a unique structural framework and versatile recognition features based on the multiple recognition sites. These include π electron stacking, charge transfer, hydrogen bonding and ion-exchange...
October 7, 2016: Analytical Chemistry
Bojidarka Ivanova, Michael Spiteller
The research draws on experimental and theoretical data about energetics and kinetics of mass spectrometric (MS) reactions of glycyl homopenta- (G5) and glycyl homohexapeptides (G6). It shows the great applicability of the methods of quantum chemistry to predict MS profile of peptides using energetics of collision induced dissociation (CID) fragment species. Mass spectrometry is among irreplaceable methods, providing unambiguous qualitative, quantitative and structural information about analytes, applicable to many scientific areas like environmental chemistry; food chemistry; medicinal chemistry; and more...
October 5, 2016: Biopolymers
Qingqing Sun, Yanchao Lü, Lingling Liu, Kaiqiang Liu, Rong Miao, Yu Fang
Supramolecular approach plays pivotal role in the construction of smart and functional materials due to the reversible nature of noncovalent interactions. In the present work, two compounds, cholesterol-functionalized calix[4]pyrrole (CCP) and perylene bisimide diacid (PDA), were synthesized. Little fluorescence is observed in the ethanol solution of the mixture of CCP and PDA, while the solution turns fluorescent upon introduction of ammonia, which is attributed to the formation of a supramolecular ensemble, PDA/(CCP)2/NH3...
October 5, 2016: ACS Applied Materials & Interfaces
Mélanie Flaender, Guillaume Costa, Guillaume Nonglaton, Christine Saint-Pierre, Didier Gasparutto
DNA is under continuous assault by environmental and endogenous reactive oxygen and alkylating species, inducing the formation of mutagenic, toxic and genome destabilizing nucleobase lesions. Due to the implications of such genetic alterations in cell death, aging, inflammation, neurodegenerative diseases and cancer, many efforts have been devoted to developing assays that aim at analyzing DNA repair activities from purified enzymes or cell extracts. The present work deals with the conception and application of a new, miniaturized and parallelized on surface-DNA biosensor to measure base excision repair (BER) activities...
September 22, 2016: Analyst
Vivian Huynh, Zachary J Sasiene, Phillip M Mach, Teresa D Golden, Guido F Verbeck
Laser ablation has been applied to redacted documents, where the text has been concealed by other ink. This technique strips the redacting ink revealing the text that was once redacted. Once removed, a nanomanipulation technique is used to extract the ink of the underlying text where mass spectrometry is then implemented to analyze its ink chemistry. In order to facilitate microscopy with direct analyte-probed nanoextraction coupled to nanospray ionization mass spectrometry (DAPNe-NSI-MS), laser ablation must be executed prior to ink extraction...
September 2016: Science & Justice: Journal of the Forensic Science Society
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