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Analytical chemistry

Mohamed Reda Aouad, Mariem Mohammed Mayaba, Arshi Naqvi, Sanaa K Bardaweel, Fawzia Faleh Al-Blewi, Mouslim Messali, Nadjet Rezki
BACKGROUND: 1,2,4-Triazoles and 1,2,3-triazoles have gained significant importance in medicinal chemistry. RESULTS: This study describes a green, efficient and quick solvent free click synthesis of new 1,2,3-triazole-4,5-diesters carrying a lipophilic side chain via 1,3-dipolar cycloaddition of diethylacetylene dicarboxylate with different surfactant azides. Further structural modifications of the resulting 1,2,3-triazole diesters to their corresponding 1,2,4-triazole-3-thiones via multi-step synthesis has been also investigated...
November 21, 2017: Chemistry Central Journal
John A Lucey, Don Otter, David S Horne
Understanding the chemistry of milk and its components is critical to the production of consistent, high-quality dairy products as well as the development of new dairy ingredients. Over the past 100 yr we have gone from believing that milk has only 3 protein fractions to identifying all the major and minor types of milk proteins as well as discovering that they have genetic variants. The structure and physical properties of most of the milk proteins have been extensively studied. The structure of the casein micelle has been the subject of many studies, and the initial views on submicelles have given way to the current model of the micelle as being assembled as a result of the concerted action of several types of interactions (including hydrophobic and the formation of calcium phosphate nanoclusters)...
December 2017: Journal of Dairy Science
Cas Weykamp, Carla Siebelder
HbA1c is a key parameter in diabetes management. For years the test has been used exclusively for monitoring of long-term diabetic control. However, due to improvement of the performance, HbA1c is considered more and more for diagnosis and screening. With this new application, quality demands further increase. A task force of the International Federation of Clinical Chemistry and Laboratory Medicine developed a model to set and evaluate quality targets for HbA1c. The model is based on the concept of total error and takes into account the major sources of analytical errors in the medical laboratory: bias and imprecision...
November 1, 2017: Journal of Diabetes Science and Technology
Joanna Legat, Magdalena Matczuk, Andrei R Timerbaev, Maciej Jarosz
The cellular uptake of gold nanoparticles (AuNPs) may (or may not) affect their speciation, but information on the chemical forms in which the particles exist in the cell remains obscure. An analytical method based on the use of capillary electrophoresis hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) has been proposed to shed light on the intracellular processing of AuNPs. It was observed that when being introduced into normal cytosol, the conjugates of 10-50 nm AuNPs with albumin evolved in human serum stayed intact...
November 15, 2017: Analytical and Bioanalytical Chemistry
Shihua Yu, Zhigang Liu, Weixian Wang, Li Jin, Weiqing Xu, Yuqing Wu
The technique of solid phase micro-extraction (SPME) is an important method for sample pretreatment in analytical chemistry, especially for the analysis in micro-systems. Surface enhanced Raman scattering (SERS) is an ultra-sensitive and fast detection technique. Both are particularly important in qualitative analysis of trace amount of substance. In this study, combining the magnetic nanoparticles with magnetic SPME device, we develop a high efficient new pretreatment method named as disperse magnetic solid phase micro-extraction (Dis-MSPME)...
February 1, 2018: Talanta
Miora Koloina Ranaivosoa, Sébastien Ganel, Arnaud Agin, Sarah Romain, Xavier Parent, Nathalie Reix
In clinical chemistry, many immunoassays apply biotin and streptavidin in the assay principle. Presence of high levels of biotin in patient samples can produce negative or positive interference depending on the assay format. In this study, we describe 2 clinical cases with chronic kidney failure and with unusual thyroid and parathyroid function test results due to biotin interference. We studied the impact of biotin levels on thyroid stimulating hormone (TSH), free thyroxine (T4L) and parathormone (PTH) results with a pool of sera loaded with several concentrations of biotin...
November 10, 2017: Néphrologie & Thérapeutique
Chengbin Sun, Tingkun Chen, Weidong Ruan, Bing Zhao, Qian Cong
Typically, the surface-enhanced Raman scattering (SERS) technique is employed in precious metallic substrates with spontaneously adsorbed probing molecules to acquire signals. Preferred chemical conditions including aggregate status, hydrophilic/hydrophobic surroundings, and smart linkers were created to enable the detection of targets in very low concentrations (lower than 1.0 × 10(-7) M). Although the sensitivity of SERS is applicable to certain areas, it is not satisfied in several cases that require obtaining good resolved signals involving extremely few surface molecules...
November 22, 2017: Analytica Chimica Acta
Cyrille Hamon, Luis M Liz-Marzán
This feature article focuses on the use of colloid chemistry to engineer metallic nanostructures toward application in surface enhanced Raman scattering (SERS) sensing, in particular for 'real-life' applications, where the analyte may be present in complex mixtures. We present a broad summary of the field, including recent advances that have been developed during the past 10 years. Real-life applications require a rational design and we aimed at identifying the key elements involved in it. The discussion is centered around colloidal plasmonic nanoparticles and therefore we start from the library of morphologies that have been reported in the literature...
November 2, 2017: Journal of Colloid and Interface Science
Thatipamula R Prasad, Siji Joseph, Prashant Kole, Anoop Kumar, Murali Subramanian, Sudha Rajagopalan, Prabhakar Kr
AIM: Objective of the current work was to develop a 'green chemistry' compliant selective and sensitive supercritical fluid chromatography-tandem mass spectrometry method for simultaneous estimation of risperidone (RIS) and its chiral metabolites in rat plasma. Methodology & results: Agilent 1260 Infinity analytical supercritical fluid chromatography system resolved RIS and its chiral metabolites within runtime of 6 min using a gradient chromatography method. Using a simple protein precipitation sample preparation followed by mass spectrometric detection achieved a sensitivity of 0...
November 9, 2017: Bioanalysis
Ramesh Asapu, Radu-George Ciocarlan, Nathalie Claes, Natan Blommaerts, Matthias Minjauw, Tareq Ahmad, Jolien Dendooven, Pegie Cool, Sara Bals, Siegfried Denys, Christophe Detavernier, Silvia Lenaerts, Sammy W Verbruggen
Silver nanoparticles are widely used in the field of plasmonics because of their unique optical properties. The wavelength-dependent surface plasmon resonance gives rise to a strongly enhanced electromagnetic field, especially at so-called hot spots located in the nanogap in-between metal nanoparticle assemblies. Therefore, the interparticle distance is a decisive factor in plasmonic applications, such as surface-enhanced Raman spectroscopy (SERS). In this study, the aim is to engineer this interparticle distance for silver nanospheres using a convenient wet-chemical approach and to predict and quantify the corresponding enhancement factor using both theoretical and experimental tools...
November 16, 2017: ACS Applied Materials & Interfaces
Charlotte M Sevrain, Mathieu Berchel, Hélène Couthon, Paul-Alain Jaffrès
The phosphonic acid functional group, which is characterized by a phosphorus atom bonded to three oxygen atoms (two hydroxy groups and one P=O double bond) and one carbon atom, is employed for many applications due to its structural analogy with the phosphate moiety or to its coordination or supramolecular properties. Phosphonic acids were used for their bioactive properties (drug, pro-drug), for bone targeting, for the design of supramolecular or hybrid materials, for the functionalization of surfaces, for analytical purposes, for medical imaging or as phosphoantigen...
2017: Beilstein Journal of Organic Chemistry
Susan D Richardson, Thomas A Ternes
This biennial review covers developments in water analysis for emerging environmental contaminants over the period of October 2015-October 2017. Analytical Chemistry's policy is to limit reviews to a maximum of ~250 significant references and to mainly focus on new trends. Therefore, only a small fraction of the quality research publications are discussed. The previous Water Analysis review (with Susana Kimura) was published in 2016.1 This year, Thomas Ternes has joined back again to cover the section on Pharmaceuticals and Hormones...
November 7, 2017: Analytical Chemistry
María Laura Soriano, Mohammed Zougagh, Miguel Valcárcel, Ángel Ríos
The main aim of this paper is to offer an objective and critical overview of the situation and trends in Analytical Nanoscience and Nanotechnology (AN&N), which is an important break point in the evolution of Analytical Chemistry in the XXI century as they were computers and instruments in the second half of XX century. The first part of this overview is devoted to provide a general approach to AN&N by describing the state of the art of this recent topic, being the importance of it also emphasized. Secondly, particular but very relevant trends in this topic are outlined: the analysis of the nanoworld, the so "third way" in AN&N, the growing importance of bioanalysis, the evaluation of both nanosensors and nanosorbents, the impact of AN&N in bioimaging and in nanotoxicological studies, as well as the crucial importance of reliability of the nanotechnological processes and results for solving real analytical problems in the frame of Social Responsibility (SR) of science and technology...
January 15, 2018: Talanta
Jennifer L Colangelo
Mass spectrometry (MS) has become a key platform in the clinical pathology laboratory and is being used more frequently for clinical pathology assessments in preclinical species for drug development studies. MS assays are being utilized for some traditional clinical pathology end points as well as novel biomarker analyses. For effective deployment in drug development toxicology studies, assays must be validated for use, and these validations are not very different from other bioanalytical platforms commonly found in the clinical pathology laboratory...
January 1, 2017: Toxicologic Pathology
Guilherme L Alexandrino, Gustavo R de Sousa, Francisco de A M Reis, Fabio Augusto
The enhanced chromatographic capability of the comprehensive two-dimensional gas chromatography (GC×GC) has already found several applications in analytical chemistry comprising complex samples. However, setting the appropriate chromatographic conditions that maximize sensitivity and separation efficiency in GC×GC may be more difficult than in conventional one-dimension gas chromatography, mainly due to the additional parameters strictly related to the modulation. Loop-type cryogenic modulators have been currently used for crude oil analysis using GC×GC, requiring sometimes a laborious try-and-error procedure to properly tune the dual-jets elapsed times on modulation...
October 25, 2017: Journal of Chromatography. A
Yan Zhang, G M Dilshan Godaliyadda, Nicola Ferrier, Emine B Gulsoy, Charles A Bouman, Charudatta Phatak
Analytical electron microscopy and spectroscopy of biological specimens, polymers, and other beam sensitive materials has been a challenging area due to irradiation damage. There is a pressing need to develop novel imaging and spectroscopic imaging methods that will minimize such sample damage as well as reduce the data acquisition time. The latter is useful for high-throughput analysis of materials structure and chemistry. In this work, we present a novel machine learning based method for dynamic sparse sampling of EDS data using a scanning electron microscope...
October 23, 2017: Ultramicroscopy
Charla Marshall, Kimberly Sturk-Andreaggi, Jennifer Daniels-Higginbotham, Robert Sean Oliver, Suzanne Barritt-Ross, Timothy P McMahon
Next-generation ancient DNA technologies have the potential to assist in the analysis of degraded DNA extracted from forensic specimens. Mitochondrial genome (mitogenome) sequencing, specifically, may be of benefit to samples that fail to yield forensically relevant genetic information using conventional PCR-based techniques. This report summarizes the Armed Forces Medical Examiner System's Armed Forces DNA Identification Laboratory's (AFMES-AFDIL) performance evaluation of a Next-Generation Sequencing protocol for degraded and chemically treated past accounting samples...
September 8, 2017: Forensic Science International. Genetics
Agatha A van der Klaauw
BACKGROUND: The global rise in the prevalence of obesity and associated comorbidities such as type 2 diabetes, cardiovascular disease, and cancer represents a major public health concern. CONTENT: Studies in rodents with the use of global and targeted gene disruption, and mapping of neurocircuitry by using optogenetics and designer receptors exclusively activated by designer drugs (DREADDs) have greatly advanced our understanding of the neural control of body weight...
November 2, 2017: Clinical Chemistry
Juan M Lorenzi, Thomas Stecher, Karsten Reuter, Sebastian Matera
Many problems in computational materials science and chemistry require the evaluation of expensive functions with locally rapid changes, such as the turn-over frequency of first principles kinetic Monte Carlo models for heterogeneous catalysis. Because of the high computational cost, it is often desirable to replace the original with a surrogate model, e.g., for use in coupled multiscale simulations. The construction of surrogates becomes particularly challenging in high-dimensions. Here, we present a novel version of the modified Shepard interpolation method which can overcome the curse of dimensionality for such functions to give faithful reconstructions even from very modest numbers of function evaluations...
October 28, 2017: Journal of Chemical Physics
Shimaa Eissa, Nawal Alshehri, Anas M Abdel Rahman, Majed Dasouki, Khalid M Abu Salah, Mohammed Zourob
Spinal muscular atrophy is an untreatable potentially fatal hereditary disorder caused by loss-of-function mutations in the survival motor neuron (SMN) 1 gene which encodes the SMN protein. Currently, definitive diagnosis relies on the demonstration of biallelic pathogenic variants in SMN1 gene. Therefore, there is an urgent unmet need to accurately quantify SMN protein levels for screening and therapeutic monitoring of symptomatic newborn and SMA patients, respectively. Here, we developed a voltammetric immunosensor for the sensitive detection of SMN protein based on covalently functionalized carbon nanofiber-modified screen printed electrodes...
October 10, 2017: Biosensors & Bioelectronics
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