Search results for "Samples"

showing 10 items of 133 documents

Determination of phenolic compounds in surface waters using high-performance liquid chromatography and molecularly imprinted solid-phase extraction

2021

An effective and reliable analytical method based on molecularly imprinted solid-phase extraction (MI-SPE) and high-performance liquid chromatography with photodiode array detector was developed to simultaneously determine four phenolic compounds: bisphenol A, 2-phenylphenol, tert-octylphenol and nonylphenol. A molecularly imprinted polymer that can selectively recognize bisphenol A and alkylphenols was developed. A bulk polymerization method using bisphenol A as a template, acrylamide as functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, acetonitrile as porogenic solvent and 1,1’-azobis(cyclohexanecarbonitrile) as initiator was applied. This polymer was applied …

Solid-phase extractionBisphenol AMolecularly imprinted polymersSurface water samplesAlkylphenolsDESALINATION AND WATER TREATMENT
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Selection of sampling adsorbents and optimisation and validation of a GC-MS/MS method for airborne pesticides

2017

ABSTRACTA methodology for the sampling and determination of airborne pesticides has been developed. The trapping efficiency of three adsorbents, namely XAD-2,XAD-4 and a sandwich sorbent (PUF-XAD2-PUF), was tested for 34 pesticides and the latter was selected because it presented the highest retention capacity without breakthrough. Pesticides were determined by gas chromatography coupled to an ion trap mass spectrometer in tandem. The method showed recoveries ranging from 70% to 120% with limits of quantification in the range of 16.1–322.6 pg m−3 when 155 m3 were sampled. This analytical strategy was applied to 10 indoor air samples collected in dwellings from the Valencian Region. Six pest…

SorbentHealth Toxicology and MutagenesisBifenthrinSoil Science010501 environmental sciences01 natural sciencesAnalytical ChemistryCypermethrinchemistry.chemical_compoundEnvironmental ChemistryWaste Management and Disposal0105 earth and related environmental sciencesWater Science and TechnologyChromatography010401 analytical chemistryPublic Health Environmental and Occupational HealthPesticidePollution0104 chemical scienceschemistryEnvironmental chemistryPesticides GC-MS/MS adsorbents gaseous phase air samplesPyrimethanilIon trapGas chromatographyGas chromatography–mass spectrometryInternational Journal of Environmental Analytical Chemistry
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GHB related acids are useful in routine casework of suspected GHB intoxication cases

2021

Abstract GHB related acids (3,4-dihydroxy butyric acid, 2,4-dihydroxy butyric acid and glycolic acid) are produced through oxidative GHB metabolism. These analytes could be potential biomarkers to ensure the diagnosis of a GHB intoxication and even prolong the detection window. Within this study, forensic routine cases were measured to consider the potential of additional gas chromatographic mass spectrometric analysis on these acids. 17 GHB positive real cases (10 serum samples and 7 urine samples) and 40 cases with suspicion of drugging in DFC cases and negative GHB results (21 serum samples and 19 urine samples) were evaluated. Increased GHB related acid concentrations were detected in a…

Succinic AcidUrinePharmacology01 natural sciencesGas Chromatography-Mass SpectrometryPathology and Forensic MedicineButyric acidForensic Toxicology03 medical and health scienceschemistry.chemical_compoundα oxidation0302 clinical medicineHumansMedicine030216 legal & forensic medicineGlycolic acidbusiness.industryPoisoning010401 analytical chemistrySerum samplesMass spectrometricGlycolates0104 chemical scienceschemistryPotential biomarkersButyric AcidSodium OxybatebusinessLawBiomarkersForensic Science International
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Anomalous magnetic hysteresis in the microwave surface resistance of MgB2 superconductor

2007

We report experimental results of the field-induced variations of the microwave surface resistance in samples of MgB2, produced by different methods. By sweeping the DC magnetic field at increasing and decreasing values, we have detected a magnetic hysteresis that can be ascribed to the different magnetic induction, due to the critical state of the fluxon lattice. The hysteresis observed in the bulk samples has an unusual shape, which cannot be justified in the framework of the critical-state models.

SuperconductivitySuperconductivityHistoryMicrowave surface resistanceMaterials scienceCondensed matter physicsFluxonMgB2Condensed Matter - SuperconductivitySettore FIS/01 - Fisica SperimentaleFOS: Physical sciencesMagnetic hysteresismicrowave surface impedanceComputer Science ApplicationsEducationElectromagnetic inductionMagnetic fieldSuperconductivity (cond-mat.supr-con)Lattice (order)Bulk samplesCondensed Matter::Superconductivity
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Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samp…

2021

In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obta…

TechnologyMultivariate statisticsSample (statistics)molecularly imprinted polymers; pesticides; environmental samples; agricultural samples; multi-criteria decision analysisArticleenvironmental samplesagricultural samplesGeneral Materials ScienceSample preparationProcess engineeringMicroscopyQC120-168.85business.industryTQH201-278.5Extraction (chemistry)Molecularly imprinted polymerSorptionpesticidesPesticideEngineering (General). Civil engineering (General)multi-criteria decision analysisTK1-9971Descriptive and experimental mechanicsmolecularly imprinted polymersEnvironmental scienceAnalytical proceduresElectrical engineering. Electronics. Nuclear engineeringTA1-2040businessMaterials
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Serological Evidence for Multiple Strains of Canine Norovirus in the UK Dog Population

2013

International audience; Noroviruses are associated with intestinal disease in humans, cows, pigs, mice, and, more recently, dogs. In 2007, the first canine norovirus (CNV) was identified and characterized in Italy. Subsequent studies have identified CNV in stools of dogs from Portugal, Greece, and the United States. To investigate the prevalence of CNV in the UK dog population, 228 canine stool samples were screened for CNV by qPCR, and 396 serum samples were screened for anti-CNV antibodies. qPCR of RNA extracted from canine stool samples did not reveal any CNV-positive samples, based on samples collected from diarrhoeic and control dogs in 2012-2013. CNV virus-like particles to three diff…

Veterinary medicineTime Factorsgenetic structuresSerological evidencelcsh:Medicinemedicine.disease_causeAntibodies ViralSeroepidemiologic Studies[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseaseslcsh:Science[SDV.MP.VIR] Life Sciences [q-bio]/Microbiology and Parasitology/Virology0303 health scienceseducation.field_of_studyMultidisciplinarybiologyGeneral Medicine3. Good health[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology[SDV.MHEP.MI] Life Sciences [q-bio]/Human health and pathology/Infectious diseasesRNA ViralAntibodyGeneral Agricultural and Biological SciencesResearch ArticlePopulationCross ReactionsGeneral Biochemistry Genetics and Molecular BiologyVirusSingle strain03 medical and health sciencesDogsSpecies SpecificitymedicineSeroprevalenceAnimalsSerologic Testseducation030304 developmental biology030306 microbiologybusiness.industrylcsh:RNorovirusSerum samplesVirologyUnited Kingdomeye diseasesNorovirusbiology.proteinlcsh:Qsense organsbusiness
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Intraoperative alteration of the total clearance of ascorbic acid in plasma

2003

Ascorbic acid (AA) is an important antioxidant in the plasma and has the tendency to postoperatively reduced values. This could be caused by an increased antioxidative activity of AA as a radical scavenger since operations are a well-known scenario of oxidative stress with increased radical production. There is some evidence for an intraoperative onset of oxidative stress which could be related to an increased antioxidative activity of AA. Therefore, the total clearance (Cltot) of AA was calculated pre- and intraoperatively in 20 neurosurgical patients. At both times plasma samples were taken before, and 15, 30, 60 and 120 minutes after an iv. AA-bolus of 4 mg/kg AA/body weight. Cltot of AA…

Vitaminmedicine.medical_specialtyNutrition and DieteticsAntioxidantPlasma samplesEndocrinology Diabetes and Metabolismmedicine.medical_treatmentmedicine.disease_causeAscorbic acidBody weightPathophysiologychemistry.chemical_compoundEndocrinologyEndocrinologychemistryAnesthesiaInternal medicineBlood plasmamedicineOxidative stressNutrition Research
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Modular Breath Analyzer (MBA): Introduction of a Breath Analyzer Platform Based on an Innovative and Unique, Modular eNose Concept for Breath Diagnos…

2021

Exhaled breath analysis for early disease detection may provide a convenient method for painless and non-invasive diagnosis. In this work, a novel, compact and easy-to-use breath analyzer platform with a modular sensing chamber and direct breath sampling unit is presented. The developed analyzer system comprises a compact, low volume, temperature-controlled sensing chamber in three modules that can host any type of resistive gas sensor arrays. Furthermore, in this study three modular breath analyzers are explicitly tested for reproducibility in a real-life breath analysis experiment with several calibration transfer (CT) techniques using transfer samples from the experiment. The experiment …

calibration transferComputer scienceRespiratory SystemPharmaceutical ScienceOrganic chemistrycorrelation alignment01 natural scienceseNoseAnalytical Chemistry0302 clinical medicineQD241-441DDC 570 / Life sciencesDrug Discoverybreath analysisSensortechnikdigestive oral and skin physiologyAtemgasanalyseMischoxideExhalationChemistry (miscellaneous)piecewise direct standardization030220 oncology & carcinogenesisElektronische NaseCalibrationMolecular MedicineMOX sensorsSpectrum analyzerAdolescentlow sensing chamber volumeReal-time computingstandard samplesbreath samplingArticleElectronic nose03 medical and health sciencesddc:570Breath testsCalibrationHumansddc:610Physical and Theoretical ChemistryReproducibilitybusiness.industry010401 analytical chemistryBreath samplingpattern recognitionBreath diagnosticsAtemluftModular design0104 chemical sciencesBreath analyzerBreath gas analysisbusinessBiosensing techniquesDDC 610 / Medicine & healthBiomarkersMolecules
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First Chemosensor for Selective Detection and Quantification of L-4-Hydroxyproline in Collagen and Other Bio Samples.

2017

Amino pyridine-based rhodamine conjugate (APR) has been developed as a first chemosensor for selective detection and quantification of L-4-Hydroxyproline (Hyp). The “turn-on” fluorescence property of the chemosensor makes it unique for easy estimation of Hyp in collagen and biological samples. peerReviewed

collagenPyridines010402 general chemistry01 natural sciencesAnalytical ChemistryRhodaminesRhodamine03 medical and health scienceschemistry.chemical_compoundHydroxyprolineamino pyridine-based rhodamine conjugate0302 clinical medicinebio samplesPyridinehydroxyprolineta116Density Functional TheoryFluorescent DyesChromatographyRhodaminesFluorescence0104 chemical sciencesselective detectionHydroxyprolinechemistry030220 oncology & carcinogenesischemosensorsCollagenConjugateAnalytical chemistry
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