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Preparation of molecularly imprinted polymer nanobeads for selective sensing of carboxylic acid vapors.
Abstract 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 crossl...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Liu C, Shang L, Yoshioka HT, Chen B, Hayashi K Tags: Anal Chim Acta Source Type: research

Trace determination of antimony by hydride generation atomic absorption spectrometry with analyte preconcentration/atomization in a dielectric barrier discharge atomizer.
zer J Abstract 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 (0.15 ng mL-1 Sb) is comparable to that observed in QTA...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Zurynková P, Dědina J, Kratzer J Tags: Anal Chim Acta Source Type: research

Feature expansion by a continuous restricted Boltzmann machine for near-infrared spectrometric calibration.
Abstract 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....
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Harrington PB Tags: Anal Chim Acta Source Type: research

A simple and automated sample preparation system for subsequent halogens determination: Combustion followed by pyrohydrolysis.
Abstract 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 NH4OH) 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 con...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Pereira LSF, Pedrotti MF, Vecchia PD, Pereira JSF, Flores EMM Tags: Anal Chim Acta Source Type: research

Highly sensitive glucose sensor based on monodisperse palladium nickel/activated carbon nanocomposites.
Abstract 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 Electr...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Koskun Y, Şavk A, Şen B, Şen F Tags: Anal Chim Acta Source Type: research

Rapid screening of basic colorants in processed vegetables through mass spectrometry using an interchangeable thermal desorption electrospray ionization source.
Abstract 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....
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Chao YY, Chen YL, Lin HY, Huang YL Tags: Anal Chim Acta Source Type: research

Label-free and sensitive microRNA detection based on a target recycling amplification-integrated superlong poly(thymine)-hosted copper nanoparticle strategy.
Abstract 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 ...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Xu F, Luo L, Shi H, He X, Lei Y, Tang J, He D, Qiao Z, Wang K Tags: Anal Chim Acta Source Type: research

Formulation of DNA chimera templates: Effects on emission behavior of silver nanoclusters and sensing.
Abstract 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. Using adenos...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Lee ST, Beaumont D, Su XD, Muthoosamy K, New SY Tags: Anal Chim Acta Source Type: research

A regenerated "turn on" fluorescent probe for sulfide detection in live cells and read samples based on dihydroxyhemicyanine-Cu2+ dye.
A regenerated "turn on" fluorescent probe for sulfide detection in live cells and read samples based on dihydroxyhemicyanine-Cu2+ dye. Anal Chim Acta. 2018 Jun 20;1010:69-75 Authors: Li H Abstract A novel "turn-on" fluorescence probe (HHC)2-Cu2+ for sulfide (S2-) was synthesized and characterized based on dihydroxyhemicyanine-Cu2+ complex. The probe displayed high sensitivity and selectivity for S2- 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 cons...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Li H Tags: Anal Chim Acta Source Type: research

Green-modified micellar liquid chromatography for isocratic isolation of some cardiovascular drugs with different polarities through experimental design approach.
Abstract 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 opti...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Ramezani AM, Absalan G, Ahmadi R Tags: Anal Chim Acta Source Type: research

Quantitative determination of non-lactose milk oligosaccharides.
net T Abstract 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. (2) by preparing a calib...
Source: Analytica Chimica Acta - February 16, 2018 Category: Chemistry Authors: Austin S, Bénet T Tags: Anal Chim Acta Source Type: research

Highly selective and sensitive fluorescence sensing of nanomolar Zn2+ ions in aqueous medium using Calix[4]arene passivated Carbon Quantum Dots based on fluorescence enhancement: Real-time monitoring and intracellular investigation.
Abstract Carbon Quantum Dots (CDs) owing to its unique photophysical properties have attracted immense consideration of the researchers in last decade to explore its applications in the fields of bio-imaging and sensing. In the present work, we have developed a novel CDs functionalized with Calix[4]arene derivative by hydrothermal route to detect biologically pertinent Zn2+ ions. Surface modification of CDs enhances fluorescence efficiency apart from introducing active surface sites broadening its sensor capabilities. The obtained surface-functionalized CDs exhibits a strong blue fluorescence under UV light (365...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Kaur H, Raj P, Sharma H, Verma M, Singh N, Kaur N Tags: Anal Chim Acta Source Type: research

Direct analysis of aluminum alloys by CSigma laser-induced breakdown spectroscopy.
We report the application of CSigma laser-induced breakdown spectroscopy (Cσ-LIBS) to quantitative analysis of aluminum alloys without sample preparation. Cσ-LIBS simplifies strongly the conventional calibration procedure of LIBS, replacing it with a characterization stage performed from the spectrum of a single standard sample. The aim of this work has been to provide a complete evaluation of the use of Cσ-LIBS for direct analysis by obtaining its figures of merit, including precision and limits of detection. Ten elements (Si, Fe, Cu, Mn, Mg, Cr, Ni, Zn, Ti and Ca) are determined in a set of six certifie...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Aragón C, Aguilera JA Tags: Anal Chim Acta Source Type: research

Robust boosting neural networks with random weights for multivariate calibration of complex samples.
Abstract 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. The performance of RBNNRW is tested with three spectral dat...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Bian X, Diwu P, Zhang C, Lin L, Chen G, Tan X, Guo Y, Cheng B Tags: Anal Chim Acta Source Type: research

Nearest clusters based partial least squares discriminant analysis for the classification of spectral data.
Abstract 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 o...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Song W, Wang H, Maguire P, Nibouche O Tags: Anal Chim Acta Source Type: research

A novel DNA sensor based on C60NPs-PAMAM-PtPNPs to detect VKORC1 gene for guiding rational clinical therapy with warfarin.
Abstract 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). Platinum porous nanopar...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Wan Y, Xu L, Zhuo N, Lu X Tags: Anal Chim Acta Source Type: research

In-syringe solid-phase extraction for on-site sampling of pyrethroids in environmental water samples.
Abstract 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. Environmental degr...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Han Q, Aydan T, Yang L, Zhang X, Liang Q, Ding M Tags: Anal Chim Acta Source Type: research

Dried blood spots and parallel artificial liquid membrane extraction-A simple combination of microsampling and microextraction.
tad A Abstract 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. In one procedure...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Ask KS, Øiestad EL, Pedersen-Bjergaard S, Gjelstad A Tags: Anal Chim Acta Source Type: research

Detection of catechol using an electrochemical biosensor based on engineered Escherichia coli cells that surface-display laccase.
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. coli whole cell laccase-based catalytic system. When the proposed biosensor ...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Zhang Z, Liu J, Fan J, Wang Z, Li L Tags: Anal Chim Acta Source Type: research

Ultrasensitive detection of EGFR gene based on surface plasmon resonance enhanced electrochemiluminescence of CuZnInS quantum dots.
Abstract 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. An ultrasensitive and universal detectin...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Chen X, Gui W, Ma Q Tags: Anal Chim Acta Source Type: research

Electrospin-coating of nitrocellulose membrane enhances sensitivity in nucleic acid-based lateral flow assay.
Abstract 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 nanoparticl...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Yew CT, Azari P, Choi JR, Li F, Pingguan-Murphy B Tags: Anal Chim Acta Source Type: research

Detection of urinary spermine by using silver-gold/silver chloride nanozymes.
Abstract 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 wit...
Source: Analytica Chimica Acta - February 11, 2018 Category: Chemistry Authors: Kuo PC, Lien CW, Mao JY, Unnikrishnan B, Chang HT, Lin HJ, Huang CC Tags: Anal Chim Acta Source Type: research

Quantitative and rapid detection of C-reactive protein using quantum dot-based lateral flow test strip.
Abstract A novel QD-based immunoassay on a paper-based lateral flow system has been developed to quantitatively detect C-reactive protein (CRP). Different standard CRP antigens from 1 to 200 μg mL-1 were diluted 200-fold and only 60 μL diluted sample were needed to load onto the sample pad. The QD fluorescence signals on the test line and the control line were able to be observed within 3 min after the initiation of assay, and the limit of detection was as sensitive as 0.30 ng mL-1 by measuring the fluorescence intensity immediately afterwards with fluorescence immunoassay analyzer. The lineari...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Wu R, Zhou S, Chen T, Li J, Shen H, Chai Y, Li LS Tags: Anal Chim Acta Source Type: research

"Turn-off" fluorescent sensor based on double quantum dots coupled with chemometrics for highly sensitive and specific recognition of 53 famous green teas.
"Turn-off" fluorescent sensor based on double quantum dots coupled with chemometrics for highly sensitive and specific recognition of 53 famous green teas. Anal Chim Acta. 2018 May 30;1008:103-110 Authors: Hu O, Xu L, Fu H, Yang T, Fan Y, Lan W, Tang H, Wu Y, Ma L, Wu D, Wang Y, Xiao Z, She Y Abstract Fluorescent "turn-off" sensors based on double quantum dots (QDs) has attracted increasing attention in the detection of many materials due to their properties such as more useful information, higher fluorescence efficiency and stability compared with the fluorescent "turn-off&qu...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Hu O, Xu L, Fu H, Yang T, Fan Y, Lan W, Tang H, Wu Y, Ma L, Wu D, Wang Y, Xiao Z, She Y Tags: Anal Chim Acta Source Type: research

Triethylamine-assisted Mg(OH)2 coprecipitation/preconcentration for determination of trace metals and rare earth elements in seawater by inductively coupled plasma mass spectrometry (ICP-MS).
Abstract In this paper, we report an improved magnesium hydroxide, Mg(OH)2, coprecipitation method for the determination of 16 trace elements (Al, V, Cr, Mn, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Sb, Sn and Pb) and 18 rare earth elements (REEs), including Sc, Y, U and Th in seawater and estuarine water samples. The procedure involves coprecipitation of the trace elements and REEs on Mg(OH)2 upon addition of a small volume of triethylamine (TEA) followed by analysis of the dissolved pellet solutions by inductively coupled plasma mass spectrometry (ICP-MS). Three-step sequential coprecipitation was carried out on 10...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Arslan Z, Oymak T, White J Tags: Anal Chim Acta Source Type: research

Voltammetric determination of tartaric acid in wines by electrocatalytic oxidation on a cobalt(II)-phthalocyanine-modified electrode associated with multiway calibration.
to VB Abstract The electrocatalytic oxidation of tartaric acid on a carbon paste electrode modified with cobalt (II)-phthalocyanine was demonstrated and applied to the development of a highly sensitive, simple, fast and inexpensive voltammetric sensor to determine tartaric acid. The electrochemical behavior of the modified electrode was investigated by cyclic and square wave voltammetry, and the effect of experimental variables, such as dispersion and loading of cobalt (II)-phthalocyanine, together with optimum conditions for sensing the analyte by square wave voltammetry were assessed. In addition, the absence of...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Lourenço AS, Nascimento RF, Silva AC, Ribeiro WF, Araujo MCU, Oliveira SCB, Nascimento VB Tags: Anal Chim Acta Source Type: research

Synthesis of gold-palladium nanowaxberries/dodecylamine-functionalized graphene quantum dots-graphene micro-aerogel for voltammetric determination of peanut allergen Ara h 1.
Abstract The paper reports synthesis of gold-palladium nanowaxberries(AuPd NWs)/dodecylamine-functionalized graphene quantum dots(D-GQDs)-graphene micro-aerogel(GMA). D-GQDs was used as a solid particle surfactant for stabilizing Pickering emulsion of toluene-in-graphene oxide aqueous dispersion. Graphene oxide sheets in the aqueous phase are reduced by hydrazine hydrate, diffused into the toluene droplet and self-assembled into graphene oxide micro-gels. Followed by freeze-drying, thermal annealing and hybridized with AuPd NWs. The as-prepared AuPd NWs/D-GQDs-GMA shows an unique three-dimensional structure with t...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Li R, Liu L, Zhu H, Li Z Tags: Anal Chim Acta Source Type: research

A novel aptamer-based online magnetic solid phase extraction method for the selective determination of 8-hydroxy-2'-deoxyguanosine in human urine.
Abstract In this work, an innovative magnetic aptamer adsorbent (Fe3O4-aptamer MNPs) was synthesized for the selective extraction of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Amino-functionalized-Fe3O4 was crosslinked with 8-OHdG aptamer by glutaraldehyde and fixed into a steel stainless tube as the sorbent of magnetic solid phase extraction (MSPE). After selective extraction by the aptamer adsorbent, the adsorbed 8-OHdG was desorbed dynamically and online analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). The synthesized sorbent presented outstanding features, including specific selectivi...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Gan H, Xu H Tags: Anal Chim Acta Source Type: research

Highly selective determination of ultratrace inorganic arsenic species using novel functionalized miniaturized membranes.
Abstract A simple method for highly selective determination of trace and ultratrace arsenic ions, i.e. arsenite and arsenate, was developed. The method is based on new miniaturized membranes, 5 mm diameter and 4.4 mg weight, which are prepared by synthesis of amorphous silica coating on cellulose fibers followed by the modification with (3-mercaptopropyl)-trimethoxysilane. The batch adsorption experiments show that membranes have high selectivity toward arsenite in the presence of heavy metals and anions that usually exist in natural water. Arsenite can be quantitatively adsorbed at pH 1 from 50 mL sample wi...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Lukojko E, Talik E, Gagor A, Sitko R Tags: Anal Chim Acta Source Type: research

Improved approach for routine monitoring of 129I activity and 129I/127I atom ratio in environmental samples using TMAH extraction and ICP-MS/MS.
In this study, great efforts were made to realize mild TMAH (tetramethyl ammonium hydroxide) extraction of environmental samples at 90 °C to obtain solutions suitable for the following triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-QQQ) MS/MS mode analysis. After releasing iodine from organic matter in the TMAH extraction solution via K2S2O8 oxidation, organic matter was removed effectively by solvent extraction and back-extraction to avoid a serious matrix effect during ICP-QQQ analysis. At the same time, interfering elements, especially, Mo, Cd, and In were also removed effectively, to avoid th...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Yang G, Tazoe H, Yamada M Tags: Anal Chim Acta Source Type: research

High-pressure photon ionization time-of-flight mass spectrometry combined with dynamic purge-injection for rapid analysis of volatile metabolites in urine.
Abstract Small molecule metabolites are widely used as biomarkers in the research field of metabolomics for disease diagnosis and exposure assessment. As a readily available biofluid containing plenty of volatile organic metabolites (VOMs), urine is ideal for non-invasive metabolomic analysis; however, there is still lack of rapid analysis method for VOMs in urine. Here we report a kind of rapid method for urine analysis by employing high-pressure photon ionization time-of-flight mass spectrometry (HPPI-TOFMS) combined with dynamic purge-injection. Various types of metabolites, such as ketones, alcohols, acids, su...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Wang Y, Hua L, Jiang J, Xie Y, Hou K, Li Q, Wu C, Li H Tags: Anal Chim Acta Source Type: research

Investigation of hydride generation from arsenosugars - Is it feasible for speciation analysis?
, Dědina J Abstract Hydride generation (HG) from arsenosugars (dimethylarsinoylribosides) in batch and flow injection modes was studied. Its efficiency was found higher in H2SO4 medium than in HCl and higher in the batch mode than in the flow injection mode. To increase the efficiency in the flow injection mode a new generator with two inlets of NaBH4 solution was designed. This modified generator was interfaced between a HPLC column and an atomic fluorescence detector. The arsenosugars studied yielded HG efficiencies in the range 13-30% most probably due to a complicated mechanism of HG. While the mechanism incl...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Marschner K, Musil S, Mikšík I, Dědina J Tags: Anal Chim Acta Source Type: research

Double labelling of intracellular mitochondria and nucleolus using thiophene pyridium salt with high quantum yield as biosensor and its application in stimulated emission depletion nanoscopy.
Abstract Probe for dual-site target distinct subcellular compartments from cytosol and nucleus is an attractive approach, however, which was scarcely reported. Herein, a series of small-molecular thiophene pyridium salt derivatives (MitoNuc1-4) possessing water-soluble, high quantum yield and two-photon activity were rationally designed, and their structures were crystallographic confirmed. Systematic photophysical and biological imaging property investigations were carried out for them. It was found that MitoNuc1-4 exhibit two-photon absorption properties in the near infrared region, and MitoNuc1 has membrane per...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Tian X, Wang H, Zhang Q, Zhang M, Zhu Y, Chen Y, Wu J, Tian Y Tags: Anal Chim Acta Source Type: research

Nickel-mediated allosteric manipulation of G-quadruplex DNAzyme for highly selective detection of histidine.
Abstract Since abnormal metabolism of histidine (His) is defined as an indicator of several diseases, detection of His in biological fluids becomes increasingly urgent to us. However, due to similar structures and properties of different amino acids, selective quantification of His is difficulty, and typically needs the participation of special reagents. In this work, we report for the first time that nickel ions (Ni2+) can induce the allostery of G-quadruplex, and is thus able to manipulate the activity of G-quadruplex DNAzyme. Experimental results indicate the interaction between Ni2+ and guanine is critical to ...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Li Z, Zhao J, Wang Z, Dai Z Tags: Anal Chim Acta Source Type: research

Amplified fluorescence detection of serum prostate specific antigen based on metal-dependent DNAzyme assistant nanomachine.
Abstract An amplified fluorescence biosensing strategy for serum prostate specific antigen (PSA) was developed on the basis of DNAzyme. In presence of cofactor Zn2+, Zn2+ -dependent DNAzyme could cleave the hairpin substrate probes which were dispersed in solution and generate remarkable fluorescent signal. Taking advantage of the magnetic beads as a carrier, one target protein could bring plentiful hairpin substrate probes on to the electrode through a sandwich structure (Ab1/PSA/biotin-Ab2). Moreover, during the cleavage process of as formed DNAzyme, DNAzyme did not be destroyed and could further react with othe...
Source: Analytica Chimica Acta - February 9, 2018 Category: Chemistry Authors: Li B, Liu J, Zhou H Tags: Anal Chim Acta Source Type: research

Simultaneous detections of genetic fragment and single nucleotide mutation with a three-tiered output for tuberculosis diagnosis.
We report a diagnostic system that uses a molecular beacon probe and an assistant strand as the core to simultaneously interact with an M.tb-specific fragment (in IS6110) and a single nucleotide substitution (SNS)-encoded segment (in rpoB) associated with drug resistance. A single fluorescent output in three-tiered levels was produced for combinatorial interpretations based on formation of a four-way DNA junction (4WJ). The SNS caused the 4WJ to partially dissociate, thus resulting in medium-level fluorescence. By contrast, high- and low-level fluorescence, represented the complete complementary complex and absence of eith...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Huang SY, Chang JR, Liao YC, Dou HY, Chuang MC Tags: Anal Chim Acta Source Type: research

Additive Partial Least Squares for efficient modelling of independent variance sources demonstrated on practical case studies.
r M Abstract A model recalibration method based on additive Partial Least Squares (PLS) regression is generalized for multi-adjustment scenarios of independent variance sources (referred to as additive PLS - aPLS). aPLS allows for effortless model readjustment under changing measurement conditions and the combination of independent variance sources with the initial model by means of additive modelling. We demonstrate these distinguishing features on two NIR spectroscopic case-studies. In case study 1 aPLS was used as a readjustment method for an emerging offset. The achieved RMS error of prediction (1.91 a.u.) was...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Luoma P, Natschläger T, Malli B, Pawliczek M, Brandstetter M Tags: Anal Chim Acta Source Type: research

A high resolution atmospheric pressure matrix-assisted laser desorption/ionization-quadrupole-orbitrap MS platform enables in situ analysis of biomolecules by multi-mode ionization and acquisition.
In this study, an AP/MALDI source with ultra-high spatial resolution was coupled to a Q Exactive HF orbitrap mass spectrometer for high resolution in situ analysis by MALDI, laserspray ionization (LSI) and matrix assisted ionization (MAI) without instrument modification. LSI and MAI generated multiply charged ions, which expanded the mass detection range and improved fragmentation efficiency. Full MS, targeted MS/MS, data dependent acquisition (DDA) and parallel reaction monitoring (PRM) acquisitions were performed on peptide and protein standards, tissue extracts and tissue sections for in depth characterization of variou...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Chen B, OuYang C, Tian Z, Xu M, Li L Tags: Anal Chim Acta Source Type: research

Single cell patterning for high throughput sub-cellular toxicity assay.
This article reports a new single cell array based toxicity assay, in which cell responses at population level, single cell level and sub-cellular level can be obtained simultaneously at high throughput. The single cell array was produced by microcontact printing and selected area cell attachment, and exposed to damaging X-ray radiation, which was followed by fluorescence imaging after staining. Two image processing softwares written in Python and MATLAB were used to determine the expressions of proteins associated with cell migration and invasion, and production of reactive oxygen species (ROS), respectively. The results ...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Xia J, Qiu Y, Xun X, Ma L, Guan J, Su M Tags: Anal Chim Acta Source Type: research

Rotational paper-based electrochemiluminescence immunodevices for sensitive and multiplexed detection of cancer biomarkers.
Abstract This paper describes a novel rotational paper-based analytical device (RPAD) to implement multi-step electrochemiluminescence (ECL) immunoassays. The integrated paper-based rotational valves can be easily controlled by rotating paper discs manually and this advantage makes it user-friendly to untrained users to carry out the multi-step assays. In addition, the rotational valves are reusable and the response time can be shortened to several seconds, which promotes the rotational paper-based device to have great advantages in multi-step operations. Under the control of rotational valves, multi-step ECL immu...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Sun X, Li B, Tian C, Yu F, Zhou N, Zhan Y, Chen L Tags: Anal Chim Acta Source Type: research

Citrate-capped silver nanoparticles as a probe for sensitive and selective colorimetric and spectrophotometric sensing of creatinine in human urine.
In this study, a simple and inexpensive sensor comprising monodisperse, citrate-capped silver nanoparticles (cc-AgNPs) was developed, which enabled rapid, sensitive and selective quantitation of creatinine directly in unprocessed urine. The mechanism of this sensor entails the creatinine-mediated aggregation of the cc-AgNPs (within 1 min) under alkaline conditions (pH 12). This is attributed to the tautomerization of creatinine to its amino anionic species at alkaline pH, which cross-link the cc-AgNPs via hydrogen bond networks with the negatively charged citrate caps. Creatinine elicited visibly-discernable color change...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Alula MT, Karamchand L, Hendricks NR, Blackburn JM Tags: Anal Chim Acta Source Type: research

Double-enhanced lateral flow immunoassay for potato virus X based on a combination of magnetic and gold nanoparticles.
This study presents the joint use of magnetic nanoparticles (MNPs) and gold nanoparticles (GNPs) for double enhancement in a lateral flow immunoassay (LFIA). The study realizes two types of enhancement: (1) increasing the concentration of analytes in the samples using conjugates of MNPs with specific antibodies and (2) increasing the visibility of the label through MNP aggregation caused by GNPs. The proposed strategy was implemented using a LFIA for potato virus X (PVX), a significant potato pathogen. MNPs conjugated with biotinylated antibodies specific to PVX and GNPs conjugated with streptavidin were synthesized and ch...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Razo SC, Panferov VG, Safenkova IV, Varitsev YA, Zherdev AV, Dzantiev BB Tags: Anal Chim Acta Source Type: research

The label-free immunosensor based on rhodium@palladium nanodendrites/sulfo group functionalized multi-walled carbon nanotubes for the sensitive analysis of carcino embryonic antigen.
Abstract In this work, bimetallic core-shell rhodium@palladium nanodendrites (Rh@Pd NDs) loaded on sulfo group functionalized multi-walled carbon nanotubes (MWCNTs-SO3H) were combined to form Rh@Pd NDs/MWCNTs-SO3H nanocomposites. And the composites were used to construct a simple and label-free electrochemical immunosensor for carcino embryonic antigen (CEA) detection using differential pulse voltammetry (DPV). Rh@Pd NDs with dendritic nanostructure not only provide abundant catalytically active sites, but also increase the loading of antibody, which could improve the analytical performance and result in high sens...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Lv H, Li Y, Zhang X, Gao Z, Feng J, Wang P, Dong Y Tags: Anal Chim Acta Source Type: research

Simultaneous determination of 11 phthalate esters in bottled beverages by graphene oxide coated hollow fiber membrane extraction coupled with supercritical fluid chromatography.
In this study, a rapid, sensitive and green method by graphene oxide coated hollow fiber membrane extraction (GO-HFME) coupled with supercritical fluid chromatography (SFC) was proposed for the determination of 11 phthalate esters in bottled beverages. Graphene oxide (GO) was prepared and coated onto a porous hollow fiber membrane (HFM) to reinforce the efficiency of membrane extraction. The modified hollow fiber membrane was employed for the extraction of phthalate esters from bottled beverages prior to the determination by the supercritical fluid chromatography with UV detection. To achieve the maximum extraction efficie...
Source: Analytica Chimica Acta - February 8, 2018 Category: Chemistry Authors: Lou C, Guo D, Zhang K, Wu C, Zhang P, Zhu Y Tags: Anal Chim Acta Source Type: research

Optical and surface plasmonic approaches to characterize extracellular vesicles. A review.
r R Abstract Extracellular vesicles (EVs) have been recognized as messengers delivering various active molecules between cells. This feature of EVs drew the attention of clinicians as well as researchers from different fields. However, exciting ideas to employ EVs as means of drug delivery or to test them as biomarkers of cellular status require very thoughtful and attentive approaches to the selection of analytical techniques for EV characterization. Optical and surface plasmonic analytical methods offer a researcher an invaluable opportunity to use already sized and/or quantified EVs in further functional cell-b...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Shpacovitch V, Hergenröder R Tags: Anal Chim Acta Source Type: research

Diethyldithiocarbamate enhanced chemical generation of volatile palladium species, their characterization by AAS, ICP-MS, TEM and DART-MS and proposed mechanism of action.
J, Musil S Abstract Comprehensive investigation of chemical generation of volatile species (VSG) of palladium for detection by analytical atomic and mass spectrometry and, specifically, the mechanistic aspects of their formation and tentative identification are presented. VSG was achieved in a flow injection mode using a generator that permitted rapid mixing of acidified sample with NaBH4 reductant. Atomization in a diffusion flame with detection by atomic absorption spectrometry was exclusively used for optimization of generation conditions while inductively coupled plasma mass spectrometry was utilized to inves...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Vyhnanovský J, Kratzer J, Benada O, Matoušek T, Mester Z, Sturgeon RE, Dědina J, Musil S Tags: Anal Chim Acta Source Type: research

Regulating immobilization performance of metal-organic coordination polymers through pre-coordination for biosensing.
Abstract We propose a method for regulating biomolecules immobilization performance of metal-organic coordination polymers (MOCPs) through pre-coordination for highly sensitive biosensing. 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was used as organic monomers. Firstly, using CuCl2 as the source of metal ions to form short oligomers with DMcT (MOCPsCu), which can regulate the length of ligands through pre-coordination. Then exploiting NaAuCl4 as the source of Au ions to coordinate both short oligomers and biomolecules (MOCPsCu+Au), since Au ions can coordinate with both N and S atoms. Through controlling the concentr...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Yang H, Qi X, Wang X, Wang X, Wang Q, Qi P, Wang Z, Xu X, Fu Y, Yao S Tags: Anal Chim Acta Source Type: research

Semi-automated set-up for exhaustive micro-electromembrane extractions of basic drugs from biological fluids.
aacute;ň P Abstract Manual handling of microliter volumes of samples and reagents is usually prone to errors and may have direct consequence on the overall performance of microextraction process. Direct connection of a syringe pump and a disposable microextraction unit using flexible polymeric tubing was employed for semi-automated liquid handling in micro-electromembrane extraction (μ-EME). A three-phase μ-EME system was formed by consecutive withdrawal of microliter volumes of donor solution, free liquid membrane (FLM) and acceptor solution into the unit. Excellent repeatability and accuracy of the withdr...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Dvořák M, Seip KF, Pedersen-Bjergaard S, Kubáň P Tags: Anal Chim Acta Source Type: research

Ionic liquid based ultrasound assisted dispersive liquid-liquid micro-extraction for simultaneous determination of 15 neurotransmitters in rat brain, plasma and cell samples.
Abstract Neurotransmitters are signaling molecules which play a key role in the central nervous system allowing signal transmission in the neuronal synapses. The role of these compounds is very crucial in the biological systems. A rapid, sensitive, economical and derivatisation free method has been developed for the analysis of 15 neurotransmitters in a single run on liquid chromatography tandem mass spectrometry. These 15 neurotransmitters are categorized into 5 groups on the basis of their fragmentation pattern. The proposed method "ionic liquid based ultrasound assisted dispersive liquid-liquid microextrac...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Jha RR, Singh C, Pant AB, Patel DK Tags: Anal Chim Acta Source Type: research

Sodium dodecyl sulfate removal during electrospray ionization using cyclodextrins as simple sample solution additive for improved mass spectrometric detection of peptides.
Abstract Sodium dodecyl sulfate (SDS) removal is a vital procedure in SDS-assisted bottom-up proteomics because SDS affects the quality of the data in electrospray ionization mass spectrometry (ESI-MS). SDS removal methods provide efficient removal of SDS and improved peptide analysis, but would usually require time, specialised devices, and experienced analysts. Here, by simple addition of γ-cyclodextrin (γ-CD) to the solution at concentrations 1 to 2x the SDS in the sample, the SDS related signals in positive ionization ESI-MS can be significantly removed (70-99% reduction), without an additional sam...
Source: Analytica Chimica Acta - February 2, 2018 Category: Chemistry Authors: Quirino JP Tags: Anal Chim Acta Source Type: research