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Recent advances in assessing xenobiotics migrating from packaging material - A review.
Abstract Migration of potentially toxic xenobiotics and their transformation products from packaging materials needs continuous monitoring efforts. This task requires utilizing both instrumental and biological methods as more and more novel materials reach market every year to serve consumers and reduce production costs. Unfortunately, these materials very often sneak past our legal regulations on their composition and emission of contaminants due to contact with the materials or products stored. For these reasons, more and more novel, holistic and multi-tier approaches must be elaborated to uncompromisingly assur...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Szczepańska N, Kudłak B, Namieśnik J Tags: Anal Chim Acta Source Type: research

A highly selective colorimetric and ratiometric fluorescent probe for instantaneous sensing of Hg2+ in water, soil and seafood and its application on test strips.
Abstract A new simple and efficient oligothiophene-based colorimetric and ratiometric fluorescent probe has been developed for highly sensitive and fast detection of Hg2+ in water, soil and seafood. The probe 5-(1,3-dithiolan-2-yl)-2,2':5',2″-terthiophene 3 TS can selectively detect Hg2+ via the Hg2+-promoted deprotection reaction of thioacetals, which caused a remarkable color change from colorless to yellow and a strong fluorescence enhancement with emission color varying from blue to yellow, enabling naked-eye detection of Hg2+. The probe shows high sensitivity with the detection limit down to 1.03 &t...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Lan L, Niu Q, Li T Tags: Anal Chim Acta Source Type: research

Preparation of carbon quantum dots from cigarette filters and its application for fluorescence detection of Sudan I.
Abstract Carbon quantum dots (CQDs) with quantum yield of 14% were successfully synthesized via a simple, low-cost, and green hydrothermal treatment using cigarette filters as carbon source for the first time. The obtained CQDs showed a strong emission at the wavelength of 465 nm, with an optimum excitation of 365 nm.Sudan I with maximum absorption wavelength at 477 nm could selectively quench the fluorescence of CQDs. Based on this principle, a fluorescence probe was developed for Sudan I determination. Furthermore, the quenching mechanism of the CQDs was elucidated. A linear relationship was found in the r...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Anmei S, Qingmei Z, Yuye C, Yilin W Tags: Anal Chim Acta Source Type: research

Retracted: Imprinted ZnO nanostructure-based electrochemical sensing of calcitonin: A clinical marker for medullary thyroid carcinoma.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor following concerns raised by various readers. The article reports different electron micrographs for different sample preparations, but some images are of different areas from the same sample. Figure 4E is a magnified section of Figure 4C, and the images are identical as demonstrated by overlapping the images and adjusting for magnification scale. The article reports EDX spectra in Figure 5C an...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Patra S, Roy E, Madhuri R, Sharma PK Tags: Anal Chim Acta Source Type: research

Highly sensitive impedimetric biosensor for Hg2+ detection based on manganese porphyrin-decorated DNA network for precipitation polymerization.
Abstract In this work, a highly sensitive impedimetric biosensor was developed for mercuric ion (Hg2+) detection. The biosensor design was based on Hg2+-triggered exonuclease III (Exo III) cleavage for target recycling and DNAzyme-mediated catalytic for precipitation polymerization. Hg2+ induced thymine-thymine (T-T) mismatches were used to trigger the Exo III-catalyzed target recycling and produce free single-stranded DNA (defined as M). The outputted M then assisted the in formation of a DNA network on electrode surface to efficiently immobilize the porphyrin manganese (MnTmPyP). The formed MnTMPyP-double-strand...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Xie S, Tang Y, Tang D, Cai Y Tags: Anal Chim Acta Source Type: research

Electrochemiluminescence immunoassay based on site-specific labeling using a histidine-binding iridium(III) solvento complex.
Abstract Histidine bound bis-cyclometalated iridium (III) complexes were found to be luminescent in previous studies. This work demonstrates that the luminophores could be excited electrochemically and the electrogenerated chemiluminescence was observed in both homogeneous solutions and on the surface of magnetic beads. The findings laid a foundation for novel ECL immunoassay methodology featuring site-specific labeling of antibodies and on-site formation of signal-generating units. Taking use of the findings and the unique advantages of the site-specific labeling approach, a sandwich immunoassay for a clinically ...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Zhou M, Xia Y Tags: Anal Chim Acta Source Type: research

Development and application of vortex-assisted membrane extraction based on metal-organic framework mixed-matrix membrane for the analysis of estrogens in human urine.
Abstract A vortex-assisted membrane extraction (VA-ME) method based on several metal-organic framework mixed-matrix membranes (MOF-MMMs) was firstly developed and applied for the analysis of four estrogens in human urine. The MOF-MMMs, with high MOF loading (∼67 wt%), were prepared using a facile approach by embedding the MOFs in a polyvinylidene difluoride matrix. The method was suitable for a wide variety of MOF materials, and the incorporated MOFs retained their unique properties. Being model analytes, the estrogens became adsorbed on the MOFs in the vortex-stirred sample solutions and were subsequently d...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Gao G, Li S, Li S, Zhao L, Wang T, Hou X Tags: Anal Chim Acta Source Type: research

A comparison study of nanofiber, microfiber, and new composite nano/microfiber polymers used as sorbents for on-line solid phase extraction in chromatography system.
Švec F, Šatínský D Abstract Three different approaches has been used to obtain nano/micro fibers and their diversity and extraction properties were examined. The effect of their structure on stability in an ultra-high-performance liquid chromatography (UHPLC) system during on-line SPE procedure was monitored. Five types of various nano/micro fiber polymers were used as sorbents: polyamide 6 nanofibers, polyvinylidene difluoride nanofibers, polyethylene microfibers, and two new polycaprolactone microfiber/nanofiber and polycaprolactone microfibers/polyvinylidene difluoride nanofibers co...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Háková M, Havlíková LC, Chvojka J, Erben J, Solich P, Švec F, Šatínský D Tags: Anal Chim Acta Source Type: research

Exploring the potential of needle trap microextraction combined with chromatographic and statistical data to discriminate different types of cancer based on urinary volatomic biosignature.
In this study, we evaluated the efficiency of an innovative methodology, Needle Trap Microextraction (NTME), combined with gas chromatography-mass spectrometry (GC-MS), for the establishment of the urinary volatomic biosignature from breast (BC), and colon (CC) cancer patients as well as healthy individuals (CTL). To achieve this, 40 mL of the headspace of acidified urine (4 mL, 20% NaCl, pH = 2), equilibrated at 50 °C during 40 min, were loaded through the DVB/Car1000/CarX sorbent inside the NTD, and subjected to a GC-MS analysis. This allowed the identification of 130 VOMs from different chemical families...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Porto-Figueira P, Pereira JAM, Câmara JS Tags: Anal Chim Acta Source Type: research

Multiplex polymerase chain reaction in combination with gel electrophoresis-inductively coupled plasma mass spectrometry: A powerful tool for the determination of gene copy number variations and gene expression changes.
es-Bayón M Abstract During the last few years multiplex real-time or quantitative polymerase chain reaction PCR (qPCR) has become the method of choice for multiplex gene expression changes and gene copy number variations (CNVs) analysis. However, such determinations require the use of different fluorescent labels for the different amplified sequences, which increases significantly the costs of the analysis and limits the applicability of the technique for simultaneous amplification of many targets of interest in a single reaction. In this regard, the use of the coupling between gel electrophoresis (GE) sepa...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Fernández Asensio A, Iglesias T, Cotarelo A, Espina M, Blanco-González E, Sierra LM, Montes-Bayón M Tags: Anal Chim Acta Source Type: research

A rapid and sensitive method for the analysis of lignin phenols in environmental samples using ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry with multiple reaction monitoring.
Abstract A novel ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed to enable the analysis of ultra-low levels of lignin phenols (
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Yan G, Kaiser K Tags: Anal Chim Acta Source Type: research

Thread spray mass spectrometry for direct analysis of capsaicinoids in pepper products.
Abstract Thread spray ambient ionization uses single threads as a medium for sampling and ionization. This approach was demonstrated through the detection of various capsaicinoids from the interior of pepper fruits without destruction of the sample. Pepper residues present on the thread were analyzed by the application of DC voltage and solvent to cause field-induced charged droplet generation. Capsaicinoids extracted from the sample are contained in the electrosprayed droplets and transported to the mass spectrometer for characterization. The thread spray mass spectrometry method was optimized using commercially ...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Jackson S, Swiner DJ, Capone PC, Badu-Tawiah AK Tags: Anal Chim Acta Source Type: research

Highly sensitive and visual detection of guanosine 3'-diphosphate-5'-di(tri)phosphate (ppGpp) in bacteria based on copper ions-mediated 4-mercaptobenzoic acid modified gold nanoparticles.
Abstract Guanosine 3'-diphosphate-5'-di(tri)phosphate (ppGpp) plays a crucial role in the gene expression, metabolism, growth, and other significant processes of microorganisms. In this work, a facile sensitive and visual strategy for the detection of ppGpp has been established by developing a colorimetric probe of copper ions (Cu2+)-mediated 4-mercaptobenzoic acid (4-MBA) modified gold nanoparticles (AuNPs). The sensing process was characterized by transmission electron microscopy (TEM), zeta potential, dynamic light scattering (DLS) and UV-vis spectroscopy. The strategy not only achieves desirable performance ov...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Chen J, Huang Y, Yang X, Zhang H, Li Z, Qin B, Chen X, Qiu H Tags: Anal Chim Acta Source Type: research

Development of extremely stable dual functionalized gold nanoparticles for effective colorimetric detection of clenbuterol and ractopamine in human urine samples.
Abstract New glutamic acid (Glu) and polyethylenimine (PE) functionalized ultra-stable gold nanoparticles (PE-Glu-AuNPs) were developed via a simple NaBH4 reduction method. The low toxicity and biocompatibility of PE-Glu-AuNPs were confirmed via an MTT assay in Raw 264.7 cells. Excitingly, PE-Glu-AuNPs were found to be extremely stable at room temperature up to six months and were utilized in an effective colorimetric naked eye assay of clenbuterol (CLB) and ractopamine (RCT) at pH 5. It was found that the selective assay of CLB and RCT is not affected by any other interferences (such as alanine, phenylalanine, ...
Source: Analytica Chimica Acta - May 16, 2018 Category: Chemistry Authors: Simon T, Shellaiah M, Steffi P, Sun KW, Ko FH Tags: Anal Chim Acta Source Type: research

Synthesis and electrochemical sensing application of poly(3,4-ethylenedioxythiophene)-based materials: A review.
Abstract As a significant and promising conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) has attracted considerable attention in the last decade. This review aims at giving a comprehensive illustration about current progress on the synthesis and electrochemical sensing applications of PEDOT-based materials in environmental monitoring, food and drug analysis and health care. PEDOT-based materials, such as PEDOT, functionalized PEDOT and PEDOT composites were fabricated mainly by chemical polymerization and electrochemical polymerization. Various nanostructures with large surface area, high conductivity,...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Hui Y, Bian C, Xia S, Tong J, Wang J Tags: Anal Chim Acta Source Type: research

Dual functional extracellular recording using a light-addressable potentiometric sensor for bitter signal transduction.
Abstract This paper presents a dual functional extracellular recording biosensor based on a light-addressable potentiometric sensor (LAPS). The design and fabrication of this biosensor make it possible to record both extracellular membrane potential changes and ATP release from a single taste bud cell for the first time. For detecting ATP release, LAPS chip was functionalized with ATP-sensitive DNA aptamer by covalent immobilization. Taste bud cells isolated from rat were cultured on LAPS surface. When the desired single taste bud cell was illuminated by modulated light, ATP release from single taste bud cells can...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Du L, Wang J, Chen W, Zhao L, Wu C, Wang P Tags: Anal Chim Acta Source Type: research

An amperometric glutamate biosensor for monitoring glutamate release from brain nerve terminals and in blood plasma.
Abstract An excess of the excitatory neurotransmitter, glutamate, in the synaptic cleft during hypoxia/ischemia provokes development of neurotoxicity and originates from the reversal of Na+-dependent glutamate transporters located in the plasma membrane of presynaptic brain nerve terminals. Here, we have optimized an electrochemical glutamate biosensor using glutamate oxidase and developed a biosensor-based methodological approach for analysis of rates of tonic, exocytotic and transporter-mediated glutamate release from isolated rat brain nerve terminals (synaptosomes). Changes in the extracellular glutamate conce...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Borisova T, Kucherenko D, Soldatkin O, Kucherenko I, Pastukhov A, Nazarova A, Galkin M, Borysov A, Krisanova N, Soldatkin A, El Skaya A Tags: Anal Chim Acta Source Type: research

A sensitive detection assay based on signal amplification technology for Alzheimer's disease's early biomarker in exosome.
Abstract Alzheimer's disease (AD) considered as the third health "killer" has seriously threatened the health of the elderly. However, the modern diagnostic strategies of AD present several disadvantages: the low accuracy and specificity resulting in some false-negative diagnoses, and the poor sensitivity leading to a delayed treatment. In view of this situation, a enzyme-free and target-triggered signal amplification strategy, based on graphene oxide (GO) and entropy-driven strand displacement reaction (ESDR) principle, was proposed. In this strategy, when the hairpin structure probes (H)specially binds...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Zhou J, Meng L, Ye W, Wang Q, Geng S, Sun C Tags: Anal Chim Acta Source Type: research

Ratiometric system based on graphene quantum dots and Eu3+ for selective detection of tetracyclines.
In this study, a system was established for the detection of tetracyclines (TCs) by simply mixing graphene quantum dots (GQDs) and Eu3+. The GQDs-Eu3+ system exhibits both strong emission of GQDs and weak characteristic emission of Eu3+ upon 360 nm excitation. In the presence of TCs, the luminescence of GQDs was quenched, while the luminescence of Eu3+ was significantly enhanced. It is worth to mention that the GQDs we prepared possess a lot of carboxyl groups on the surface and edge. This carboxyl groups play an important role in fluorescent enhancement of Eu3+. On the basis of this effect, a novel label free ratiometri...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Li W, Zhu J, Xie G, Ren Y, Zheng YQ Tags: Anal Chim Acta Source Type: research

Determining the number of chemical species in nuclear magnetic resonance data matrix by taking advantage of collinearity and noise.
Abstract The number of chemical species is crucial in analyzing pulsed field gradient nuclear magnetic resonance spectral data. Any method to determine the number must handle the obstacles of collinearity and noise. Collinearity in pulsed field gradient NMR data poses a serious challenge to and fails many existing methods. A novel method is proposed by taking advantage of the two obstacles instead of eliminating them. In the proposed method, the determination is based on discriminating decay-profile-dominant eigenvectors from noise-dominant ones, and the discrimination is implemented with a novel low- and high-fre...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Wang W, Shao L, Yuan B, Zhang X, Liu M Tags: Anal Chim Acta Source Type: research

Three-dimensional porous self-assembled chestnut-like nickel-cobalt oxide structure as an electrochemical sensor for sensitive detection of hydrazine in water samples.
This study proves that three-dimensional porous chestnut-like NiCo2O4 is electrochemically active for catalytic performance which is particular and promising material for good application in the practical detection of N2H4. PMID: 29729735 [PubMed] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Zhang X, Wang Y, Ning X, Li L, Chen J, Shan D, Gao R, Lu X Tags: Anal Chim Acta Source Type: research

Electrochemical and density functional theory investigation on the differential behaviors of core-ring structured NiCo2O4 nanoplatelets toward heavy metal ions.
Abstract In order to further improve the electroanalytical performance toward heavy metal ions, core-ring structured NiCo2O4 nanoplatelets were used to modify glass carbon electrode (GCE) for the determination of heavy metal ions in water. Owing to the high surface area of NiCo2O4 nanoplatelets, the Pb(II) sensitivity increased by a factor of 1.70, and the detection limit decreased by a factor of 2.64 as compared to solid NiCo2O4 nanoparticles modified GCE. Interestingly, NiCo2O4 nanoplatelets showed different sensitivities toward heavy metal ions with the same valence states, following the order Pb(II) > C...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Liao J, Zhang J, Wang CZ, Lin S Tags: Anal Chim Acta Source Type: research

Fabrication and characterization of metal organic frameworks/ polyvinyl alcohol cryogel and their application in extraction of non-steroidal anti-inflammatory drugs in water samples.
Abstract A series of novel MOFs/PVA composite cryogel (MIL-101(Cr)/PVA, MIL-100(Fe)/PVA, ZIF-8(Zn)/PVA, MOF-199(Cu)/PVA and MIL-53(Al)/PVA) were fabricated by using a facile and green freeze-thaw approach for the first time. MIL-101(Cr)/PVA cryogel was selected as a VA-SPE sorbent for extraction of four NSAIDs in environmental water samples. The procedures of condition investigation (synthesis and extraction optimization) and characterization were also performed. And a satisfactory result of methodology validation was obtained by making use of HPLC-MS/MS. Under the optimum conditions, good sensitivity levels were ...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Wang Y, Zhang Y, Cui J, Li S, Yuan M, Wang T, Hu Q, Hou X Tags: Anal Chim Acta Source Type: research

Development of a robust extraction procedure for the HPLC-ESI-HRPS determination of multi-residual pharmaceuticals in biota samples.
bic R Abstract A simple, robust and effective extraction procedure for the determination of 74 pharmaceuticals in different fish tissues by ultrasensitive high performance liquid chromatography with electrospray high resolution product scan (HPLC-ESI-HRPS) was developed and validated. Different extraction solvent mixtures were tested to achieve the highest recoveries of the selected analytes, to minimize the influence of a complex matrix and to reduce the total analysis time as well as cost of analysis. A mixture of acetonitrile + isopropanol (3:1 v/v) acidified with 0.1% formic acid was the best extract...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Grabicova K, Vojs Staňová A, Koba Ucun O, Borik A, Randak T, Grabic R Tags: Anal Chim Acta Source Type: research

Novel automated workflow for spectral alignment and mass calibration in MS imaging using a sputtered Ag nanolayer.
We present an MSI data processing workflow that uses a label-free approach to compensate for mass shifts. The algorithms developed were designed to perform efficiently even for datasets much larger than computer's memory. Herein, we present the application of the developed processing workflow to a dataset with more than 13.000 pixels and ∼50.000 mass channels. We assessed the overall mass accuracy in the range m/z 400 to 1200 using silver and gold sputtered nanolayers. With our novel processing workflow we were able to obtain mass errors as low as 5 ppm using a TOF instrument. PMID: 29729739 [PubMed] (Source: An...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Ràfols P, Castillo ED, Yanes O, Brezmes J, Correig X Tags: Anal Chim Acta Source Type: research

Quantification of steroid hormones in plasma using a surrogate calibrant approach and UHPLC-ESI-QTOF-MS/MS with SWATH-acquisition combined with untargeted profiling.
r M Abstract In spite of demonstrated lack of accuracy and consistency, quantification of steroid hormones is still most commonly executed via immunoassays. Mass spectrometric methods with triple quadrupole instruments are well established and, because of their proven robustness and sensitivity, best suited for targeted analysis. However, recent studies have shown that high-resolution mass spectrometers, like quadrupole time-of-flight instruments (QTOF), show comparable performance in terms of quantification and can generate additional sample information via untargeted profiling workflows. We demonstrate that adeq...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Drotleff B, Hallschmid M, Lämmerhofer M Tags: Anal Chim Acta Source Type: research

An untargeted evaluation of food contact materials by flow injection analysis-mass spectrometry (FIA-MS) combined with independent components analysis (ICA).
Abstract Food contact materials (FCMs), especially plastics, are known to be a potential source of contaminants in food. In fact, various groups of additives are used to protect the integrity of the material during processing and life time. However, these intentionally added substances (IAS) could also lead to degradation products called non-intentionally added substances (NIAS), due to reactions occurring in the polymeric material. Complex mixtures of components may therefore be generated within the material, creating a source of potential migrating substances towards food in contact. In this context, an innovati...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Habchi B, Kassouf A, Padellec Y, Rathahao-Paris E, Alves S, Rutledge DN, Maalouly J, Ducruet V Tags: Anal Chim Acta Source Type: research

Inkjet printing-based β-secretase fluorescence resonance energy transfer (FRET) assay for screening of potential β-secretase inhibitors of Alzheimer's disease.
Inkjet printing-based β-secretase fluorescence resonance energy transfer (FRET) assay for screening of potential β-secretase inhibitors of Alzheimer's disease. Anal Chim Acta. 2018 Aug 31;1022:89-95 Authors: Lee J, Samson AAS, Song JM Abstract Amyloid-β (Aβ) is generated by proteolytic processing of amyloid precursor protein (APP) by beta-secretase (BACE-1) and gamma-secretase. Amyloid-β is responsible for the formation of senile plaques in Alzheimer's disease (AD). Consequently, inhibition of β-secretase (BACE-1), a rate-limiting enzyme in the production of Aβ, cons...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Lee J, Samson AAS, Song JM Tags: Anal Chim Acta Source Type: research

Parametric study on mixing process in an in-plane spiral micromixer utilizing chaotic advection.
Abstract Recent advances in the field of microfabrication have made the application of high-throughput microfluidics feasible. Mixing which is an essential part of any miniaturized standalone system remains the key challenge. This paper proposes a geometrically simple micromixer for efficient mixing for high-throughput microfluidic devices. The proposed micromixer utilizes a curved microchannel (spiral microchannel) to induce chaotic advection and enhance the mixing process. It is shown that the spiral microchannel is more efficient in comparison to a straight microchannel, mixing wise. The pressure drop in the sp...
Source: Analytica Chimica Acta - May 9, 2018 Category: Chemistry Authors: Vatankhah P, Shamloo A Tags: Anal Chim Acta Source Type: research

Particle-based liquid chromatographic separations in microfluidic devices - A review.
Abstract The research and applications of liquid chromatographic (LC) chips receive more and more attention due to the numerous advantages over the traditional and larger analytical systems, e.g. requirement for small sample and reagent volumes, fast and inexpensive analysis, dead-volume free connections and the ability to multiplex measurements. Since LC is one of the most powerful separation techniques, its miniaturization seems an obvious target of lab-on-a-chip developments. However, the common procedures used in the preparation of chromatographic columns are not well applicable at the microscopic level. Addit...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Kecskemeti A, Gaspar A Tags: Anal Chim Acta Source Type: research

Diffusion-based humidity control membrane for microfluidic-based gas detectors.
Abstract This paper presents a cost-effective and reliable diffusion-based humidity removal membrane for microfluidic-based gas analyzers. The developed humidity control device reduces the relative humidity of a gas chamber and also stabilizes the humidity using inexpensive inorganic salts. A 3D-printed microfluidic gas sensor is used to test four different volatile organic compounds (VOCs) including three alcohols and one ketone in different relative humidity levels ranging from 15% to 80%. To study the effects of humidity on different features of the transient response of the sensor, two different feature extrac...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Paknahad M, Bachhal JS, Hoorfar M Tags: Anal Chim Acta Source Type: research

Uricase-free on-demand colorimetric biosensing of uric acid enabled by integrated CoP nanosheet arrays as a monolithic peroxidase mimic.
Abstract In clinical diagnosis, monitoring of uric acid (UA) is generally realized by combining uricase with natural peroxidase. The use of bio-enzymes, however, shadows some highlights of these methods due to their vulnerable activities against environments. Herein, we report a novel biosensor for the natural enzyme-free colorimetric detection of UA by using CoP nanosheet arrays grown on Ni foam (NF) as a monolithic peroxidase mimic. The integrated nanozyme can be put into and taken out from reaction systems conveniently with only tweezers, making it possible for on-demand analysis. As demonstrated, the obtained ...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: He Y, Qi F, Niu X, Zhang W, Zhang X, Pan J Tags: Anal Chim Acta Source Type: research

Electrochemical detection of sequence-specific DNA based on formation of G-quadruplex-hemin through continuous hybridization chain reaction.
Abstract A high-sensitive detection of sequence-specific DNA was established based on the formation of G-quadruplex-hemin complex through continuous hybridization chain reaction (HCR). Taking HIV DNA sequence as an example, a capture probe complementary to part of HIV DNA was firstly self-assembled onto the surface of Au electrode. Then a specially designed assistant probe with both terminals complementary to the target DNA and a G-quadruplex-forming sequence in the center was introduced into the detection solution. In the presence of both the target DNA and the assistant probe, the target DNA can be captured on t...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Sun X, Chen H, Wang S, Zhang Y, Tian Y, Zhou N Tags: Anal Chim Acta Source Type: research

In situ monitoring of cytoplasmic precursor and mature microRNA using gold nanoparticle and graphene oxide composite probes.
This study strategically fabricates a nucleic acid functionalized gold nanoparticle and graphene oxide composite probe (AuNP/GO probe) to achieve both the recognition and in situ monitoring of cytoplasmic target precursor microRNAs (pre-miRNAs) and mature microRNAs (miRNAs) in living cells. The pre-miRNA-21 detection with AuNP probes has a good linear range of 0-300 nM and a limit of detection (LOD) of 4.5 nM, whereas the GO probe has a linear relationship with mature miRNA-21 from 0.1 to 10 nM with a LOD of 1.74 nM. This assay was utilized to directly visualize the relative expression levels of pre- and mature for...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Hong M, Sun H, Xu L, Yue Q, Shen G, Li M, Tang B, Li CZ Tags: Anal Chim Acta Source Type: research

A new colorimetric sensor for visible detection of Cu(II) based on photoreductive ability of quantum dots.
This study may provide new ideas for the development of QD-based sensors. PMID: 29681280 [PubMed] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Li H, Bai H, Lv Q, Wang W, Wang Z, Wei H, Zhang Q Tags: Anal Chim Acta Source Type: research

Simultaneous classification of multiple classes in NMR metabolomics and vibrational spectroscopy using interval-based classification methods: iECVA vs iPLS-DA.
This study outlines the iECVA method and compares its performance to interval Partial Least Squares Discriminant Analysis (iPLS-DA) on three spectroscopic datasets from Nuclear Magnetic Resonance (NMR), Near Infrared (NIR) and Infrared (IR) spectroscopy, respectively. The results invariantly show that the interval-based classification methods greatly enhance the interpretability of the models by identifying important spectral regions, which facilitate interpretation and biomarker discovery. Although the results for the two methods are similar regarding the number of misclassifications and identified important regions, the ...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Rinnan Å, Savorani F, Engelsen SB Tags: Anal Chim Acta Source Type: research

A flexible and novel strategy of alternating trilinear decomposition method coupled with two-dimensional linear discriminant analysis for three-way chemical data analysis: Characterization and classification.
Abstract This paper proposes a flexible and novel strategy that alternating trilinear decomposition (ATLD) method combines with two-dimensional linear discriminant analysis (2D-LDA). The developed strategy was applied to three-way chemical data for the characterization and classification of samples. In order to confirm the methodology performances of characterization and classification, a series of simulated three-way data arrays and a real-life EEMs data set involving the characterization and classification of tea samples according to the tea varieties were subjected to ATLD-2DLDA analysis. Further, the obtained ...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Hu Y, Wu HL, Yin XL, Gu HW, Liu Z, Xiao R, Xie LX, Fang H, Yu RQ Tags: Anal Chim Acta Source Type: research

Matrix-effect-free determination of BTEX in variable soil compositions using room temperature ionic liquid co-solvents in static headspace gas chromatography mass spectrometry.
In this study, room temperature ionic liquids (RTILs) were evaluated as solvents in an effort to increase sensitivity and to reduce and normalize matrix effects associated with varying soil compositions during analysis. Headspace gas chromatography mass spectrometry (HS-GC-MS) experiments demonstrated that hydrophilic RTILs 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][ESO4], 1-ethyl-3-methylimidazolium diethyl phosphate [EMIM][DEP], and tris(2-hydroxyethyl) methylammonium methylsulfate [MTEOA][MeOSO3] normalized the response for BTEX compounds between 2 different soils, sandy loam and sandy clay loam. Furthermore, the ...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Varona-Torres E, Carlton DD, Hildenbrand ZL, Schug KA Tags: Anal Chim Acta Source Type: research

Alkylsilyl speciation and direct sample preparation of plant cannabinoids prior to their analysis by GC-MS.
In this study, trialkylsilylation of seven p-CBDs (including their transformation products formed in the drug user's body) was compared applying various alkylsilyl reagents1 and the mass fragmentation properties of the corresponding derivatives were characterized. Derivatization, mass fragmentation and quantitation related model investigations were optimized as a function of the reaction times and conditions. Special emphasis was put (i) on the maximum responses of species, (ii) on the proportions of formed stable products, suitable for selective quantitation of all seven p-CBDs simultaneously. Results, as novel to the fie...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Fodor B, Boldizsár I, Molnár-Perl I Tags: Anal Chim Acta Source Type: research

Solid phase microextraction combined with thermal-desorption electrospray ionization mass spectrometry for high-throughput pharmacokinetics assays.
Abstract Labor- and time-intensive sample preparation and liquid chromatography mass spectrometry (LC-MS) analysis are required for traditional pharmacokinetics (PK) studies. In order to simplify and accelerate the analytical process of the PK study, solid phase microextraction (SPME) combined with thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) was developed for rapid characterization of trace drug in biological fluids. Methylphenidate in plasma was extracted and concentrated by direct immersion SPME using fused-silica fibers coated with polydimethylsiloxane. The analytes on the SPME fibe...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Wang CH, Su H, Chou JH, Huang MZ, Lin HJ, Shiea J Tags: Anal Chim Acta Source Type: research

Hierarchical cluster analysis of technical replicates to identify interferents in untargeted mass spectrometry metabolomics.
Abstract Mass spectral data sets often contain experimental artefacts, and data filtering prior to statistical analysis is crucial to extract reliable information. This is particularly true in untargeted metabolomics analyses, where the analyte(s) of interest are not known a priori. It is often assumed that chemical interferents (i.e. solvent contaminants such as plasticizers) are consistent across samples, and can be removed by background subtraction from blank injections. On the contrary, it is shown here that chemical contaminants may vary in abundance across each injection, potentially leading to their misiden...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Caesar LK, Kvalheim OM, Cech NB Tags: Anal Chim Acta Source Type: research

Analytical characteristics of nano-electrospray operated under super-atmospheric pressure.
Abstract High-pressure nanoelectrospray ionization (nanoESI) source is a recently developed technique in which the electrospray ionization is generated inside an enclosed chamber with gas pressure higher than the atmospheric pressure. In this paper, the performance of nanoESI under different gas pressures, emitter position, ion inlet temperature, additive for desalination are presented. Under a pressure of 2 bars, the nanoESI is almost eased from the electrical discharge problem, and that offers a wider tuning window for the emitter potential to produces a higher and more stable ion signal. With optimized ion in...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Rahman MM, Chen LC Tags: Anal Chim Acta Source Type: research

Microvalve using electrokinetic motion of electrically induced Janus droplet.
Abstract A novel microvalve using the electrokinetic motion of electrically induced Janus droplet (EIJD) is presented in this paper. The device is fabricated by injecting an EIJD with the diameter of approximately 80 μm into a microchamber connecting several microchannel branches. The EIJD is developed from an oil droplet covered by Al2O3-nanoparticles under electric field. The microvalve is controllable by electric field. Under an electric field, the Janus droplet undergoes electrokinetic motion in the microchamber, moves to one branch channel and blocks its entrance. By switching the electric field directio...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Li M, Li D Tags: Anal Chim Acta Source Type: research

IR-Compatible PDMS microfluidic devices for monitoring of enzyme kinetics.
Abstract Coupling infrared (IR) spectroscopy to microfluidic devices provides a powerful tool for characterizing complex chemical and biochemical reactions. Examples of microfluidic devices coupled with infrared spectroscopy have been limited, however, largely due to the difficulties associated with fabricating systems in common infrared transparent materials like CaF2. Recent reports have shown that polydimethylsiloxane (PDMS) can be used as an IR transparent substrate when fabricated with thin layers. The use of soft lithography with PDMS expands the library of possible designs that can be achieved for IR measur...
Source: Analytica Chimica Acta - April 25, 2018 Category: Chemistry Authors: Srisa-Art M, Noblitt SD, Krummel AT, Henry CS Tags: Anal Chim Acta Source Type: research

A two dimensional metal-organic framework nanosheets-based fluorescence resonance energy transfer aptasensor with circular strand-replacement DNA polymerization target-triggered amplification strategy for homogenous detection of antibiotics.
Abstract In the study, a novel two dimensional metal-organic framework (Cu-TCPP nanosheets) based fluorescence resonance energy transfer (FRET) aptasensing platform was developed for detecting antibiotics. Cu-TCPP nanosheets were employed for quenching the background fluorescence and circular strand-replacement DNA polymerization (CSRP) for signal amplification. To fulfill the purpose, we designed an aptamer hairpin probe (HP) whose stem can be opened while specifically binding to target. Then the opened HP would bind with the primer. Under the action of polymerase, extension reaction was induced to generate doubl...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Yang Q, Zhou L, Wu YX, Zhang K, Cao Y, Zhou Y, Wu D, Hu F, Gan N Tags: Anal Chim Acta Source Type: research

Dual enzyme-free amplification strategy for ultra-sensitive fluorescent detection of bisphenol A in water.
Abstract An ultra-sensitive strategy for bisphenol A (BPA) detection based on dual enzyme-free strategies: hybridization chain reaction (HCR) and enzyme-strand recycling reaction has been developed. The BPA aptamer can form hairpins structure by the partly self-complementary sequence. In the presence of BPA, the released BPA aptamer sequence can trigger the HCR between two hairpins to from a long nicked double-helix DNA. The tails of hairpins on the duplex DNA were closely enough to hybridize with molecular beacon (MB) on the gold nanoparticles (AuNPs) to circularly cleave the loop of MB, leading to a "turn-o...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Yun W, Wu H, Chen L, Yang L Tags: Anal Chim Acta Source Type: research

A novel colorimetric aptasensor for ultrasensitive detection of cocaine based on the formation of three-way junction pockets on the surfaces of gold nanoparticles.
Abstract Herein, a novel colorimetric aptasensor was introduced for detection of cocaine based on the formation of three-way junction pockets on the surfaces of gold nanoparticles (AuNPs) and the catalytic activity of the surfaces of AuNPs. Simplicity and detection of cocaine in a short time (only 35 min) are some of the unique features of the proposed sensing strategy. In the presence of cocaine, triple-fragment aptamer (TFA) forms on the surfaces of AuNPs, leading to a significant decrease of the catalytic activity of AuNPs and the color of samples remains yellow. In the absence of target, TFA does not form on...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Abnous K, Danesh NM, Ramezani M, Taghdisi SM, Emrani AS Tags: Anal Chim Acta Source Type: research

Aptamer-based microcantilever-array biosensor for profenofos detection.
Abstract Profenofos, a highly poisonous organophosphorus pesticide, has been widely used in agricultural production. These pesticide residues have seriously influenced food security and threatened human health, and new methods with high sensitivity are greatly needed to detect profenofos. Here, we developed an aptamer-based microcantilever-array sensor operated in stress mode to detect profenofos, with advantages of being a label-free, highly sensitive, one-step immobilization method capable of quantitative and real-time detection. The microcantilevers were functionalized with a profenofos-specific aptamer (SS2-55...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Li C, Zhang G, Wu S, Zhang Q Tags: Anal Chim Acta Source Type: research

Aerosol sampler for analysis of fine and ultrafine aerosols.
řa Z Abstract A new aerosol sampler based on the original version of Aerosol Counterflow Two-Jets Unit (ACTJU) is described. The ACTJU collector, connected with a water-based Condensation Growth Unit (CGU) placed upstream of the ACTJU, accomplished the quantitative collection of fine and ultrafine aerosol particles down to a few nanometers in diameter. Condensation of water vapor in the CGU enlarges nanometer sized particles to larger sizes in the supermicrometer range and the formed droplets are then collected into water in the ACTJU collector. The continuous collection of aerosols with the CGU-ACTJU sampler all...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Mikuška P, Čapka L, Večeřa Z Tags: Anal Chim Acta Source Type: research

Simultaneous elastase-, hyaluronidase- and collagenase-capillary electrophoresis based assay. Application to evaluate the bioactivity of the red alga Jania rubens.
te; R Abstract There have been many efforts to search for affordable and efficient cosmetic ingredients from natural sources and to evaluate their bioactivities using eco-responsible tools. Hyaluronidase, elastase and collagenase are responsible for the degradation of the main components of the extracellular matrix, namely the hyaluronic acid, elastin and collagen, respectively. The aim of this work was to develop a single capillary electrophoresis method to monitor simultaneously the activities of these three enzymes, without reactant immobilization or radioactivity use. The developed approach was used to evaluat...
Source: Analytica Chimica Acta - April 17, 2018 Category: Chemistry Authors: Fayad S, Tannoury M, Morin P, Nehmé R Tags: Anal Chim Acta Source Type: research