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Analytica Chimica Acta

Sean Austin, Thierry Bénet
A method for the determination of non-lactose oligosaccharides (NLO) in milk using liquid chromatography has been developed. Oligosaccharides were labelled with a fluorescent tag, 2-aminobenzamide (2AB), and were identified by comparison of their retention times to those of oligosaccharide standards, their mass (as measured by mass spectrometry) and their fragmentation patterns in the mass spectrometer. The concentrations of the NLO in milk have been determined using 2 different approaches: (1) by preparing a calibration curve using genuine standards of each oligosaccharide...
June 20, 2018: Analytica Chimica Acta
Amir M Ramezani, Ghodratollah Absalan, Raheleh Ahmadi
Bilayer pseudo-stationary phase micellar liquid chromatography (MLC) was developed for simultaneous isocratic isolation of hydrochlorothiazide, as a basic-polar (hydrophilic) cardiovascular drug, as well as triamterene and losartan potassium, as acidic-nonpolar (hydrophobic) cardiovascular drugs. Utilizing a deep eutectic solvent (DES), as a novel green mobile phase additive in combination with acetonitrile (ACN) and acetic acid (ACA), drastically improved the chromatographic behavior of the drugs. Concentration of sodium dodecyl sulphate (SDS), as well as volume percentages of ACN, DES, and ACA were optimized by using a central composite design...
June 20, 2018: Analytica Chimica Acta
Hongda Li
A novel "turn-on" fluorescence probe (HHC) 2 -Cu 2+ for sulfide (S 2- ) was synthesized and characterized based on dihydroxyhemicyanine-Cu 2+ complex. The probe displayed high sensitivity and selectivity for S 2- over other analytes, including biothiols, NaCN, reactive oxygen species (ROS) and reactive nitrogen species (RNS) in aqueous solution, which was attributed to the large association constant and the fast kinetics of precipitation of CuS. The probe (HHC) 2 -Cu 2+ can be regenerated and reversibly detected with S 2- with a remarkable red-fluorescent change by alternating the addition of S 2- and Cu 2+ ...
June 20, 2018: Analytica Chimica Acta
Shi Ting Lee, David Beaumont, Xiao Di Su, Kasturi Muthoosamy, Siu Yee New
Single strand DNA (ssDNA) chimeras consisting of a silver nanoclusters-nucleating sequence (NC) and an aptamer are widely employed to synthesize functional silver nanoclusters (AgNCs) for sensing purpose. Despite its simplicity, this chimeric-templated AgNCs often leads to undesirable turn-off effect, which may suffer from false positive signals caused by interference. In our effort to elucidate how the relative position of NC and aptamer affects the fluorescence behavior and sensing performance, we systematically formulated these NC and aptamer regions at different position in a DNA chimera...
June 20, 2018: Analytica Chimica Acta
Fengzhou Xu, Lan Luo, Hui Shi, Xiaoxiao He, Yanli Lei, Jinlu Tang, Dinggeng He, Zhenzhen Qiao, Kemin Wang
Poly(thymine)-hosted copper nanoparticles (poly T-CuNPs) have emerged as a promising label-free fluorophore for bioanalysis, but its application in RNA-related studies is still rarely explored. Herein, by utilizing duplex-specific nuclease (DSN) as a convertor to integrate target recycling mechanism into terminal deoxynucleotidyl transferase (TdT)-mediated superlong poly T-CuNPs platform, a specific and sensitive method for microRNA detection has been developed. In this strategy, a 3'-phosphorylated DNA probe can hybridize with target RNA and then be cut by DSN to produce 3'-hydroxylated fragments, which can be further tailed by TdT with superlong poly T for fluorescent CuNPs synthesis...
June 20, 2018: Analytica Chimica Acta
Yu-Ying Chao, Yen-Ling Chen, Hong-Yi Lin, Yeou-Lih Huang
Thermal desorption electrospray ionization/mass spectrometry (TD-ESI-MS) employing a quickly interchangeable ionization source is a relatively new ambient ionization mass spectrometric technique that has had, to date, only a limited number of applications related to food safety control. With reallocation of resources, this direct-analysis technique has had wider use in food analysis when operated in dual-working mode (pretreatment-free qualitative screening and conventional quantitative confirmation) after switching to an ambient ionization source from a traditional atmospheric pressure ionization source...
June 20, 2018: Analytica Chimica Acta
Yağmur Koskun, Aysun Şavk, Betül Şen, Fatih Şen
Glucose enzyme biosensors have been used for a variety of applications such as medical diagnosis, bioprocess engineering, beverage industry and environmental scanning etc. and there is still a growing interest in glucose sensors. For this purpose, addressed herein, as a novel glucose sensor, highly sensitive activated carbon (AC) decorated monodisperse nickel and palladium alloy nanocomposites modified glassy carbon electrode (Ni-Pd@AC/GCE NCs) have been synthesized by in-situ reduction technique. Raman Spectroscopy (RS), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), cyclic voltammetry (CV) and chronoamperometry (CA) were used for the characterization of the prepared non-enzymatic glucose sensor...
June 20, 2018: Analytica Chimica Acta
L S F Pereira, M F Pedrotti, P Dalla Vecchia, J S F Pereira, E M M Flores
A simple and automated system based on combustion followed by a pyrohydrolysis reaction was proposed for further halogens determination. This system was applied for digestion of soils containing high (90%) and also low (10%) organic matter content for further halogens determination. The following parameters were evaluated: sample mass, use of microcrystalline cellulose and heating time. For analytes absorption, a diluted alkaline solution (6 mL of 25 mmol L -1 NH 4 OH) was used in all experiments. Up to 400 mg of soil with high organic matter content and 100 mg of soil with low organic matter content (mixed with 400 mg of cellulose) could be completely digested using the proposed system...
June 20, 2018: Analytica Chimica Acta
Peter de Boves Harrington
A modified algorithm for training a restricted Boltzmann machine (RBM) has been devised and demonstrated for improving the results for partial least squares (PLS) calibration of wheat and meat by near-infrared (NIR) spectroscopy. In all cases, the PLS calibrations improved by using the abstract features generated from the RBM so long as the nonlinear mapping increased the dimensionality. The evaluations were validated using bootstrapped Latin partitions (BLPs) with 5 bootstraps and 3-Latin partitions which proved useful because of the statistical learning and random initial conditions of the RBM networks...
June 20, 2018: Analytica Chimica Acta
Pavla Zurynková, Jiří Dědina, Jan Kratzer
Atomization conditions for antimony hydride in the plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spectrometric detection were optimized. Argon was found as the best discharge gas under a flow rate of 50 mL min - 1 while the DBD power was optimum at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection (LOD) reached in DBD (0...
June 20, 2018: Analytica Chimica Acta
Chuanjun Liu, Liang Shang, Hiro-Taka Yoshioka, Bin Chen, Kenshi Hayashi
The detection and discrimination of volatile carboxylic acid components, which are the main contributors to human body odor, have a wide range of potential applications. Here, a quartz crystal microbalance (QCM) sensor array based on molecularly imprinted polymer (MIP) nanobeads is developed for highly sensitive and selective sensing of typical carboxylic acid vapors, namely: propionic acid (PA), hexanoic acid (HA) and octanoic acid (OA). The MIP nanobeads were prepared by precipitation polymerization with methacrylic acid (MAA) as a functional monomer, trimethylolproane trimethacrylate (TRIM) as a crosslinker, and carboxylic acids (PA, HA and OA) as the template molecules...
June 20, 2018: Analytica Chimica Acta
Po-Chih Kuo, Chia-Wen Lien, Ju-Yi Mao, Binesh Unnikrishnan, Huan-Tsung Chang, Han-Jia Lin, Chih-Ching Huang
In this paper, we report a simple one-step synthesis method for silver-gold bimetallic nanoparticles deposition on silver chloride nanosheets to form Ag-Au/AgCl nanohybrid with oxidase-like and peroxidase-like catalytic activity. We used these nanohybrid in the detection of spermine. First, 13 nm-sized Au NPs were synthesized by citrate reduction of HAuCl4 solution, and then, Ag+ ions were added to the solution without any purification. The added Ag+ reacted with the Cl- ions in the dispersion, thus immediately forming AgCl nanosheets through a precipitation reaction, and the aurophilic interactions with the Au NPs resulted in the formation and in situ self-deposition of Ag-Au NPs on the AgCl nanosheets at room temperature...
June 7, 2018: Analytica Chimica Acta
Chee-Hong Takahiro Yew, Pedram Azari, Jane Ru Choi, Fei Li, Belinda Pingguan-Murphy
Point-of-care biosensors are important tools developed to aid medical diagnosis and testing, food safety and environmental monitoring. Paper-based biosensors, especially nucleic acid-based lateral flow assays (LFA), are affordable, simple to produce and easy to use in remote settings. However, the sensitivity of such assays to infectious diseases has always been a restrictive challenge. Here, we have successfully electrospun polycaprolactone (PCL) on nitrocellulose (NC) membrane to form a hydrophobic coating to reduce the flow rate and increase the interaction rate between the targets and gold nanoparticles-detecting probes conjugates, resulting in the binding of more complexes to the capture probes...
June 7, 2018: Analytica Chimica Acta
Xueqian Chen, Wenying Gui, Qiang Ma
In our work, a novel DNA electrochemiluminescence (ECL) sensor based on CuZnInS quantum dots (QDs) and gold-nanoparticles (Au NPs) is developed for highly sensitive detection of epidermal growth factor receptor (EGFR) Gene, which has a close relation with the lung cancer. The CuZnInS QDs work as a novel kind of ECL luminophore, whose defect state emission is suitable for ECL sensing. To enhance the sensitivity of the sensing system, Au NPs are utilized creatively to strengthen the ECL intensity of CuZnInS QDS according to the surface plasmon resonance (SPR) effect...
June 7, 2018: Analytica Chimica Acta
Zhen Zhang, Jin Liu, Jin Fan, Zhiyong Wang, Lin Li
In this study, we report an electrochemical microbial biosensor that was made by immobilizing a bacterial laccase on the surface of Escherichia coli cells followed by adsorption of modified live cells onto a glassy-carbon electrode. Expression and surface localization of laccase on target cells were confirmed by Western blotting, flow cytometry assays and immunofluorescence microscopy observation. Increased tandem-aligned anchors with three repeats of the N-terminal domain of an ice nucleation protein were used to construct a highly active E...
June 7, 2018: Analytica Chimica Acta
Kristine Skoglund Ask, Elisabeth Leere Øiestad, Stig Pedersen-Bjergaard, Astrid Gjelstad
In this paper, parallel artificial liquid membrane extraction (PALME) was used for the first time to clean-up dried blood spots (DBS) prior to ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Fundamental studies exploring amongst others desorption from the DBS in alkaline or acidic aqueous conditions, total extraction time and absolute recoveries were executed. Desorption and PALME were performed using a set of two 96-well plates, one of them housing the sample and the other comprising the supported liquid membrane (SLM) and the acceptor solution...
June 7, 2018: Analytica Chimica Acta
Qiang Han, Tursunjan Aydan, Liu Yang, Xiaoqiong Zhang, Qionglin Liang, Mingyu Ding
On-site sampling is an analytical approach that can ensure the accuracy of monitoring data and enhance the effectiveness of environmental protection measures. In the present work, an in-syringe solid-phase extraction (SPE) device was designed for on-site sampling of trace contaminants in environmental water samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Template assisted freeze casting followed by hydrazine vapor reduction approach was used to synthesize a hierarchical porous graphene aerogel (HPGA), which was used as the sorbent in the in-syringe SPE device...
June 7, 2018: Analytica Chimica Acta
Yongxian Wan, Lili Xu, Naiqiang Zhuo, Xiaobo Lu
Reports have indicated that warfarin is the most widely prescribed anticoagulant. However, traditionally prescribed doses for each patient may be too low or too high. The therapeutic effect is often hindered by a lack of evidence-based medical information. Herein, our aim is to provide this information. To accomplish this challenge, we report the development of a novel assay based on biotinylated tetrahedral DNA as a capture probe and fullerene (C60)-based nanomaterial as a redox probe using an ultrasensitivity assay with the Vitamin K epoxide reductase complex, subunit 1 (VKORC1)...
June 7, 2018: Analytica Chimica Acta
Weiran Song, Hui Wang, Paul Maguire, Omar Nibouche
Partial Least Squares Discriminant Analysis (PLS-DA) is one of the most effective multivariate analysis methods for spectral data analysis, which extracts latent variables and uses them to predict responses. In particular, it is an effective method for handling high-dimensional and collinear spectral data. However, PLS-DA does not explicitly address data multimodality, i.e., within-class multimodal distribution of data. In this paper, we present a novel method termed nearest clusters based PLS-DA (NCPLS-DA) for addressing the multimodality and nonlinearity issues explicitly and improving the performance of PLS-DA on spectral data classification...
June 7, 2018: Analytica Chimica Acta
Xihui Bian, Pengyao Diwu, Caixia Zhang, Ligang Lin, Guohui Chen, Xiaoyao Tan, Yugao Guo, Bowen Cheng
Neural networks with random weights (NNRW) has been used for regression due to its excellent performance. However, NNRW is sensitive to outliers and unstable to some extent in dealing with the real-world complex samples. To overcome these drawbacks, a new method called robust boosting NNRW (RBNNRW) is proposed by integrating a robust version of boosting with NNRW. The method builds a large number of NNRW sub-models sequentially by robustly reweighted sampling from the original training set and then aggregates these predictions by weighted median...
June 7, 2018: Analytica Chimica Acta
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