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https://www.readbyqxmd.com/read/28738658/an-ultrasensitive-chemiluminescence-aptasensor-for-thrombin-detection-based-on-iron-porphyrin-catalyzing-luminescence-desorbed-from-chitosan-modified-magnetic-oxide-graphene-composite
#1
Yuanling Sun, Yanhui Wang, Jianbo Li, Chaofan Ding, Yanna Lin, Weiyan Sun, Chuannan Luo
In this work, an ultrasensitive chemiluminescence (CL) aptasensor was prepared for thrombin detection based on iron porphyrin catalyzing luminol - hydrogen peroxide luminescence under alkaline conditions, and iron porphyrin was desorbed from chitosan modified magnetic oxide graphene composite (CS@Fe3O4@GO). Firstly, CS@Fe3O4@GO was prepared. CS@Fe3O4@GO has advantages of the good biocompatibility and positively charged on its surface of CS, the large specific surface area of GO and the easy separation characteristics of Fe3O4...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738653/development-of-an-efficient-method-for-multi-residue-analysis-of-160-pesticides-in-herbal-plant-by-ethyl-acetate-hexane-mixture-with-direct-injection-to-gc-ms-ms
#2
Sherif M Taha, Sohair A Gadalla
A simple and efficient multi residue method was developed, for the analysis of 160 pesticides by GC-MS/MS in herbal plants. The developed method employs pesticide residue extraction by EtAC/ n. hexane (6:4) with a cleanup step using florisil/ PSA mixture. The optimized conditions have resulted in lower co-extracted matrix components than those extracted using EtAC or MeCN (QuEChERS method), according to FTIR and full scan GC/MS analyses. In addition, the developed method (EtAC/ Hexane) eliminates the evaporation step that is usually performed when using MeCN as an extraction solvent prior to the GC-MS/MS injection...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738648/matrix-interference-evaluation-employing-gc-and-lc-coupled-to-triple-quadrupole-tandem-mass-spectrometry
#3
S Uclés, A Lozano, A Sosa, P Parrilla Vázquez, A Valverde, A R Fernández-Alba
Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the "matrix effect", which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738646/synthesis-characterization-and-application-of-a-novel-multifunctional-stationary-phase-for-hydrophilic-interaction-reversed-phase-mixed-mode-chromatography
#4
Hayriye Aral, K Serdar Çelik, Ramazan Altındağ, Tarık Aral
A novel multifunctional stationary phase based on silica gel was synthesised starting from L- isoleucine and 4-phenylbutylamine and evaluated as a hydrophilic interaction/reversed-phase mixed-mode stationary phase for high-performance liquid chromatography (HPLC). The prepared stationary phase was characterized by elemental analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM), Brunauer, Emmett and Teller (BET) and solid-state (13)C nuclear magnetic resonance (NMR). The mechanisms involved in the chromatographic separation are multi-interaction, including hydrophobic, π-π, hydrogen-bonding, dipole-dipole and ion-dipole interactions...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738630/simultaneous-determination-of-paracetamol-and-ciprofloxacin-in-biological-fluid-samples-using-a-glassy-carbon-electrode-modified-with-graphene-oxide-and-nickel-oxide-nanoparticles
#5
Anderson Martin Santos, Ademar Wong, Adriana Araújo Almeida, Orlando Fatibello-Filho
A simple and highly selective electrochemical method using a glassy carbon electrode (GCE) modified with graphene oxide (GO) and nickel oxide nanoparticles (NiONPs) was developed for the simultaneous determination of paracetamol (PAR) and ciprofloxacin (CIP). The electrochemical characterisation of the modified GCE was performed by cyclic voltammetry and electrochemical impedance spectroscopy. The morphological characterisation of the GO and NiONPs was performed by scanning electron microscopy and transmission electron microscopy...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738629/innovative-simple-and-green-ultrasound-assisted-enzyme-based-hydrolytic-microextraction-method-for-manganese-at-trace-levels-in-food-samples
#6
Erkan Yilmaz, Mustafa Soylak
We describe the usage of hydrolytic enzymes for the innovative, green and simple microextraction of manganese in food samples. The ultrasound assisted-enzyme based hydrolytic microextraction method (UA-EH-ME) was applied for the separation and determination of manganese in food samples prior to its micro-sampling flame atomic absorption spectrometric determination (MS-FAAS). Analytical parameters influenced on the enzyme based hydrolytic microextraction method such as pH, type of enzyme, amount of enzyme, temperature and time of ultrasonic waves were fully evaluated and optimized by using mg level of NCS ZC73033 scallion certified reference material...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738623/analysis-of-illegal-peptide-drugs-via-hilic-dad-ms
#7
Steven Janvier, Evelien De Sutter, Evelien Wynendaele, Bart De Spiegeleer, Celine Vanhee, Eric Deconinck
Biopharmaceuticals have established themselves as highly efficient medicines, and are still one of the fastest growing parts of the health-product industry. Unfortunately, the introduction of these promising new drugs went hand in hand with the creation of a black market for illegal and counterfeit biotechnology drugs. Particularly popular are the lyophilised peptides with a molecular weight of less than 5kDa. Most of them are meant for subcutaneous injection and are easily accessible via the internet. In recent years, different methods based on reversed phase liquid chromatography have been developed to detect and quantify these peptides...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738621/determining-heterocyclic-aromatic-amines-in-aqueous-samples-a-novel-dispersive-liquid-liquid-micro-extraction-method-based-on-solidification-of-floating-organic-drop-and-ultrasound-assisted-back-extraction-followed-by-uplc-ms-ms
#8
Romina Canales, María Guiñez, Cristian Bazán, Mario Reta, Soledad Cerutti
A novel dispersive liquid-liquid microextraction based on solidification of floating organic droplet combined with ultrasound assisted back extraction for the determination of four heterocyclic aromatic amines in natural water samples prior ultra high-performance liquid chromatography-tandem mass spectrometry was developed. The analytes were extracted from the water samples by a dispersive liquid-liquid microextraction procedure based on solidification of floating organic drop, which was performed by a mixture composed by a less dense than water extraction solvent, 1-undecanol, and a dispersive solvent, methanol...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738619/simultaneous-and-sensitive-electrochemical-detection-of-dihydroxybenzene-isomers-with-uio-66-metal-organic-framework-mesoporous-carbon
#9
Min Deng, Shourui Lin, Xiangjie Bo, Liping Guo
The zirconium-based MOF (UiO-66)/mesoporous carbon (MC) composite was synthesized using conventional hydrothermal method for the first time. The surface morphology and structure of UiO-66/MC composite were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A novel electrochemical sensor based on UiO-66/MC was constructed for simultaneous and sensitive determination of dihydroxybenzene isomers (DBIs) of hydroquinone (HQ), catechol (CT) and resorcinol (RS)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738614/in-situ-synthesis-of-reduced-graphene-oxide-gold-nanoparticles-modified-electrode-for-speciation-analysis-of-copper-in-seawater
#10
Ming Liu, Dawei Pan, Wen Pan, Yun Zhu, Xueping Hu, Haitao Han, Chenchen Wang, Dazhong Shen
In this paper, reduced graphene oxide/gold nanoparticle/Nafion (rGO/AuNP/Nafion) modified electrode was fabricated through in-situ synthesis and used for determination of copper ions in strong salt electrolyte (0.5M NaCl) by differential pulse anodic stripping voltammetry (DPASV). This in-situ synthesis procedure was based on the ion-exchange and electrochemical reduction. The use of rGO provided a larger electrode surface and the presence of more active sites, while electron transfer was accelerated by incorporating AuNPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738613/a-selective-distance-based-paper-analytical-device-for-copper-ii-determination-using-a-porphyrin-derivative
#11
Rimadani Pratiwi, Michael P Nguyen, Slamet Ibrahim, Naoki Yoshioka, Charles S Henry, Daryono H Tjahjono
Meso-tetrakis(1,2-dimethylpyrazolium-4-yl)porphyrin sulfonate (TDMPzP), a water-soluble porphyrin derivative, was synthesized and used as a colorimetric reagent for Cu(2+) detection on a microfluidic paper-based analytical device (µPAD) using distance-based quantification. TDMPzP showed a high selectivity for Cu(2+) detection in aqueous solutions. When Cu(2+) was added to the TDMPzP under acidic conditions, a color change from green to a pink was observed by the naked eye. Under optimized conditions, the application of this system to a distance-based μPAD exhibited good analytical response...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738612/sorption-luminescence-method-for-determination-of-terbium-using-transcarpathian-clinoptilolite
#12
V O Vasylechko, G V Gryshchouk, V P Zakordonskiy, L O Vasylechko, M Schmidt, I M Leshchack, Ya M Kalychak, S R Bagday
Sorption-luminescent method for terbium determination based on natural Transcarpathian clinoptilolite without using of complex synthetic organic compounds and toxic solvents was proposed. Optimal luminophore preparation conditions are sorption of Tb(III) on zeolite in the borate buffer solution with pH 8.25 and further calcination of clinoptilolite-Tb(III) samples at 500°C. For luminescence excitation the rays with wavelength of λ = 220nm of were used. Luminescence intensity at λ = 545nm was selected as analytical parameter for a quantitative terbium determination...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738611/a-novel-electrochemical-sensor-based-on-wo3-nanorods-decorated-poly-sodium-4-styrenesulfonate-functionalized-graphene-nanocomposite-modified-electrode-for-detecting-of-puerarin
#13
Shasha Jing, Huijun Zheng, Li Zhao, Lingbo Qu, Lanlan Yu
An electrochemical sensing platform was fabricated based on composition of poly(sodium 4-styrenesulfonate) (PSS), graphene (GN) and WO3 nanorods on glassy carbon electrode (GCE). The PSS-GN/WO3 nanocomposite significantly increased the oxidative activity of puerarin due to the individual merit and mutual effect of PSS-GN and WO3 nanorods which improved the performance of the electrochemical sensor with high sensitivity. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements were used for the detection of puerarin...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738606/a-label-free-fluorometric-assay-for-actin-detection-based-on-enzyme-responsive-dna-templated-copper-nanoparticles
#14
Quanwei Song, Lixia Yang, Hongkun Chen, Rong Zhang, Na Na, Jin Ouyang
Herein, we develop a fluorescent strategy for label-free detection of actin by the in situ formation of double-stranded DNA (dsDNA) templated copper nanoparticles (CuNPs) and the digestion capability of deoxyribonuclease I (DNase I). In this design, the introduction of actin can effectively hinder the enzymic digestion owing to the exceptional target-mediated conformational structure between actin and DNase I. Consequently, the remaining adenine-thymine-rich dsDNA can act as an efficient template for fluorescent CuNPs (λex = 340nm, λem = 585nm) with a Mega-Stokes shifting (245nm)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738604/electrochemical-investigation-and-determination-of-procaterol-hydrochloride-on-poly-glutamic-acid-carboxyl-functionalized-multiwalled-carbon-nanotubes-polyvinyl-alcohol-modified-glassy-carbon-electrode
#15
Dexian Kong, Lili Jiang, Yijun Liu, Zeming Wang, Libin Han, Rixin Lv, Jiandi Lin, Chun-Hua Lu, Yuwu Chi, Guonan Chen
Poly(glutamic acid) (P-GLU)/carboxyl functionalized multiwalled carbon nanotubes (MWCNTs-COOH)/polyvinyl alcohol (PVA) modified glassy carbon electrode (GCE) has been successfully prepared and the electrochemical behavior of procaterol hydrochloride (ProH) was studied. The results show that the as-prepared modified electrode exhibits a good electrocatalytic property towards the oxidation of ProH in 0.2M phosphate buffer solution (PBS) (pH 6.0) due to the enhanced oxidation peak current at ~+0.59V. Under optimal reaction conditions, the oxidation peak current of ProH is proportional to its concentration in the linear dynamic ranges of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738603/vortex-assisted-liquid-liquid-liquid-microextraction-followed-by-high-performance-liquid-chromatography-for-the-simultaneous-determination-of-fourteen-phenolic-acids-in-honey-iced-tea-and-canned-coffee-drinks
#16
Marwan Shalash, Ahmad Makahleh, Salizawati Muhamad Salhimi, Bahruddin Saad
A vortex-assisted liquid-liquid-liquid microextraction method followed by high performance liquid chromatography-diode array detection for the determination of fourteen phenolic acids (cinnamic, m-coumaric, chlorogenic, syringic, ferulic, o-coumaric, p-coumaric, vanillic, p-hydroxybenzoic, caffeic, 2, 4-dihydroxybenzoic, sinapic, gentisic and gallic acids) in honey, iced tea and canned coffee drink samples has been developed. The separation was achieved using a Poroshell 120-EC-C18 column under a gradient elution at a flow rate of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738599/development-of-a-chemiluminescent-dna-fibre-optic-genosensor-to-hepatitis-a-virus-hav
#17
Kehan Ye, Marisa Manzano, Riccardo Muzzi, Karina Yew-Hoong Gin, Nazanin Saeidi, Shin Giek Goh, Alfred Iing Yoong Tok, Robert S Marks
Hepatitis A virus (HAV) infection has caused substantial morbidity and economic losses to human society, presenting a major public health problem in many parts of the world. Despite the capability for low-concentration detection, current PCR-based techniques are limited by the requirement of specialized lab equipment, trained personnel and a relatively large time-commitment. The need for a prompt in-field quantitative identification of HAV in real samples has led us to develop a chemiluminescent fibre optic genosensor system...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738598/green-and-efficient-sample-preparation-method-for-the-determination-of-catalyst-residues-in-margarine-by-icp-ms
#18
Carla Andrade Hartwig, Rodrigo Mendes Pereira, Diogo La Rosa Novo, Dirce Taina Teixeira Oliveira, Marcia Foster Mesko
Responding to the need for green and efficient methods to determine catalyst residues with suitable precision and accuracy in samples with high fat content, the present work evaluates a microwave-assisted ultraviolet digestion (MW-UV) system for margarines and subsequent determination of Ni, Pd and Pt using inductively coupled plasma mass spectrometry (ICP-MS). It was possible to digest up to 500mg of margarine using only 10mL of 4molL(-1) HNO3 with a digestion efficiency higher than 98%. This allowed the determination of catalyst residues using the ICP-MS and free of interferences...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738597/sensitive-detection-of-sulfide-based-on-the-self-assembly-of-fluorescent-silver-nanoclusters-on-the-surface-of-silica-nanospheres
#19
Yehan Yan, Kui Zhang, Huan Yu, Houjuan Zhu, Mingtai Sun, Tasawar Hayat, Ahmed Alsaedi, Suhua Wang
Hydrogen sulfide is a toxic and flammable gaseous pollutant often emitted to air as a by-product of water supply, chemical, petroleum and coal industries. It can be transferred into sulfur dioxide in the air under some meteorologic conditions. Herein, we report a novel ratiometric fluorescence method for hydrogen sulfide based on silver nanoclusters and quantum dots. The silver nanoclusters have been self-assemblied onto the surface of silica spheres, which are embedded with red fluorescent quantum dots, to form a dual-emissive nanohybrid...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738590/extracellular-matrix-characterization-in-plaques-from-carotid-endarterectomy-by-a-proteomics-approach
#20
N Ucciferri, S Rocchiccioli, L Comelli, M Marconi, M Ferrari, G Pelosi, A Cecchettini
Extracellular matrix (ECM) is a fundamental component of multicellular organisms. Alteration of its structure and/or molecular composition are associated with several pathologies, among the others with atherosclerosis. To determine how the overall ECM architecture of a tissue as complex as the atheroma may change under varying pathological conditions constitutes a great technical challenge. This entails removing cell components and solubilisation of fibrillar proteins in order to allow enzymatic digestion and mass spectrometry analyses...
November 1, 2017: Talanta
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