Plasmonic metal nanoparticles as efficient mass tags for ion signal amplification and ultrasensitive detection of protein markers.
Abstract The development of sensitive and specific analytical methods is critical for the discovery of molecular biomarkers, which assists disease diagnosis and understanding biological processes. Herein, a highly sensitive method is developed using antibody-conjugated plasmonic metal nanoparticles for the detection of targeted biomarkers down to low attomole level via coupling of immunoassay techniques with laser ionization mass spectrometry (LI-MS). The conjugated antibodies target specific antigens, while the metal nanoparticles act as mass tags and ion reservoirs for the signal amplification. With the characte...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Cheng YH, Cheung YF, Siu-Chung Tam T, Lok CN, Sun H, Ng KM Tags: Anal Chim Acta Source Type: research

Thermophoretic diagnosis of autoimmune diseases based on Escherichia coli with autodisplayed autoantigens.
Abstract The autoimmune diseases systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS) are diagnosed by detection of autoantibodies against Ro and La protein autoantigens, respectively. In this work, the diagnosis of autoimmune diseases SLE and SS was demonstrated using thermophoresis of Escherichia coli with the autodisplayed autoantigens. Ro and La protein autoantigens were autodisplayed by constitutive expression together with a fluorescent protein called tdTomato in the cytosol. The binding affinity of the autodisplayed autoantigens was tested against positive and control sera by using FACS as a refer...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Lee GY, Bong JH, Kim JY, Yoo G, Park M, Kang MJ, Jose J, Pyun JC Tags: Anal Chim Acta Source Type: research

Specific and simultaneous detection of micro RNA 21 and let-7a by rolling circle amplification combined with lateral flow strip.
Abstract Owing to the pivotal function in post transcriptional gene modification, miRNA biomarkers are playing crucial role in tracking and diagnosing various forms of tumors in a short time period. Hence, the need to develop simple, sensitive and specific detection of miRNAs for precise diagnosis arises. This current study is aimed to develop a detecting platform by combining rolling circle amplification with AuNps-based lateral flow strip (LFS-RCA) for simultaneous detection of miRNA 21 and miRNA let-7a. The current methodology is simple, sensitive, specific and selective for miRNA let-7a and miRNA 21 with the l...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Yao M, Lv X, Deng Y, Rasheed M Tags: Anal Chim Acta Source Type: research

Homogeneous peptide-break assay for luminescent detection of enzymatic protein post-translational modification activity utilizing charged peptides.
auml; H Abstract We have developed a rapid and sensitive universal peptide-based time-resolved luminescence assay for detection of enzymatic post-translational modifications (PTMs). PTMs play essential roles in intracellular signaling and cell regulation, thus providing functional protein diversity in cell. Due this, impaired PTM patterns have been linked to multiple disease states. Clear link between PTMs and pathological conditions have also driven assay development further, but still today most of the methodologies are based on single-specificity or group-specific PTM-recognition. We have previously introduced ...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Kopra K, Tong-Ochoa N, Laine M, Eskonen V, Koskinen PJ, Härmä H Tags: Anal Chim Acta Source Type: research

A mitochondria-targeted and FRET-based ratiometric fluorescent probe for detection of SO2 derivatives in water.
Abstract A mitochondria-targeted ratiometric fluorescent probe based on the fluorophore pyrido[1,2-a]benzimidazole was developed. It showed high sensitivity and selectivity toward SO2 derivatives in water. The probe was also successfully applied to detect intrinsically generated SO2 derivatives in living glioma cells, which may be helpful in ascertaining the biological roles of SO2 in mitochondria. PMID: 30782364 [PubMed - in process] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Zhang D, Liu A, Ji R, Dong J, Ge Y Tags: Anal Chim Acta Source Type: research

Smartphone-based fluorescent lateral flow immunoassay platform for highly sensitive point-of-care detection of Zika virus nonstructural protein 1.
Abstract Simple, inexpensive, and rapid diagnostic tests in low-resource settings with limited laboratory equipment and technical expertise are instrumental in reducing morbidity and mortality from epidemic infectious diseases. We developed a smartphone-based fluorescent lateral flow immunoassay (LFIA) platform for the highly sensitive point-of-care detection of Zika virus nonstructural protein 1 (ZIKV NS1). An attachment was designed and 3D-printed to integrate the smartphone with external optical and electrical components, enabling the miniaturization of the instrument and reduction in cost and complexity. Quant...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Rong Z, Wang Q, Sun N, Jia X, Wang K, Xiao R, Wang S Tags: Anal Chim Acta Source Type: research

PtNi bimetallic nanoparticles loaded MoS2 nanosheets: Preparation and electrochemical sensing application for the detection of dopamine and uric acid.
Abstract Composite nanomaterials are particularly useful and offer many excellent opportunities for electrochemical sensing application. Depending on the high catalytic activity of bimetallic nanoparticles, the large specific surface area, abundant active edges and co-catalytic function of MoS2 nanosheets, we, for the first time, prepared a novel PtNi bimetallic nanoparticles loaded MoS2 nanosheets (PtNi@MoS2) hybrid material by a co-reduction method for the electrochemical sensing application. The nanocomposite is characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spec...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Ma L, Zhang Q, Wu C, Zhang Y, Zeng L Tags: Anal Chim Acta Source Type: research

Highly efficient Polyaniline-MoS2 hybrid nanostructures based biosensor for cancer biomarker detection.
Abstract In this work, polyaniline nanospindles have been synthesized using iron oxide as sacrificial template. These nanospindles were utilized for the fabrication of PANI-MoS2 nanoflower architectures via hydrothermal route. The electrostatic interaction between PANI and MoS2 improves the conductivity and provides more direct paths for charge transportation. SEM, TEM, XRD, Raman Spectroscopy techniques were employed to explore the crystal structure, and morphological properties of the PANI-MoS2 nanocomposite. Furthermore, an electrochemical biosensing platform based on PANI-MoS2 nanocomposite was fabricated for ...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Soni A, Pandey CM, Pandey MK, Sumana G Tags: Anal Chim Acta Source Type: research

Online profiling of living rat brain extracellular pH using a pH-Dependent solid phase extraction scheme coupled with microdialysis sampling and inductively coupled plasma mass spectrometry.
In this study, a novel analytical method was developed for online profiling of living rat brain extracellular pH. It involved microdialysis (MD) sampling, introduction of metal ions (e.g., Mn, Co, Ni, Cd) as acid/base indicators, and a pH-dependent solid phase extraction (SPE) based on polymer-metal ion interactions as a sample pretreatment scheme prior to analysis through inductively coupled plasma mass spectrometry (ICP-MS). With a 10-μL microdialysate, optimization of the system provided a working pH range from 5.8 to 8.2 and allowed differentiation of tiny changes in pH, down to a resolution of 0.015 pH units. Stand...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Su CK, Ho CC Tags: Anal Chim Acta Source Type: research

Determination of residual organophosphorus thioester pesticides in agricultural products by chemical isotope-labelling liquid chromatography-tandem mass spectrometry coupled with in-syringe dispersive solid phase clean-up and in situ cleavage.
Abstract Chemical isotope labelling in combination with high-performance liquid chromatography-tandem mass spectrometry (CIL-HPLC-MS/MS) is a powerful method for quantitative profiling of targeted molecules. In the current work, we successfully developed a novel CIL-HPLC-MS/MS method for quantitative profiling of residual organophosphorus thioester pesticides (OPTPs) in agricultural products through the determination of the cleavage products of thiol (CP-thiol) compounds. In this method, we synthesized a novel pair of CIL reagents, i.e., N-(4-(carbazole-9-yl)-phenyl)-N-maleimide (NCPM-d0) and its deuterated analog...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Yu Y, You J, Sun Z, Li G, Ji Z, Zhang S, Zhou X Tags: Anal Chim Acta Source Type: research

Spatially resolved analysis of liquid crystal displays by laser ablation-atmospheric pressure chemical ionization-mass spectrometry.
t U Abstract In recent years, liquid crystal displays (LCDs) became more and more popular in industrial and consumer electronics applications. Unevenly distributed liquid crystals (LC) and the presence of organic contaminations in the LC layer, for example from the display sealant, can cause display defects and therefore lower the display quality. This work describes the development of a fast and easy screening method for display samples by laser ablation coupled to atmospheric pressure chemical ionization-mass spectrometry (LA-APCI-MS). With this ambient technique, LC components as well as sealant materials, whic...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Müller JC, Berg T, Enders C, Leonhard P, Karst U Tags: Anal Chim Acta Source Type: research

A self-digitization chip integrated with hydration layer for low-cost and robust digital PCR.
We present a self-discretization and zero-water-loss microfluidic digital PCR (dPCR) device to enable low-cost and robust quantitative nucleic acid assays. In this device, a thin void is integrated beneath the reaction chamber array. By utilizing the permeability of polydimethylsiloxane (PDMS) film, the integrated void serves a dual function: vacuum "accumulator" and hydration "reservoir". The combination of pre-stored pumping energy and water compensation for evaporation loss enables simple, robust and reliable single-DNA-molecule amplification and detection in 10,000 reactors of picoliter volume. Comp...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Ning Y, Cui X, Yang C, Jing F, Bian X, Yi L, Li G Tags: Anal Chim Acta Source Type: research

Sub-femtomolar detection of HIV-1 gene using DNA immobilized on composite platform reinforced by a conductive polymer sandwiched between two nanostructured layers: A solid signal-amplification strategy.
This study introduces a signal amplification strategy rely on incorporating a specific polymer film between two typical nanostructured layers, aiming to improve the electrical properties of the platform to be able to transduce small binding event through sub-femtomolar detection of HIV-1 gene at the surface of the constructed biosensing device. The proposed composite was arrayed based on a conductive layer consist of p-aminobenzoic acid (PABA) sandwiched between the electrochemically reduced graphene oxide (ERGO) as the sub-layer, and the gold nanoparticles (AuNPs) as the interfacial layer. We computationally explored that...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Shamsipur M, Samandari L, Taherpour AA, Pashabadi A Tags: Anal Chim Acta Source Type: research

Paper-based microfluidic devices for glucose assays employing a metal-organic framework (MOF).
Abstract This paper describes the development of two microfluidic paper-based analytical devices (μPADs), one well-based and the other based on a lateral flow assay (LFA) configuration, to detect glucose via a colorimetric assay using the solid metal-organic framework (MOF) Zr-PCN-222(Fe), to encapsulate glucose oxidase (GOx). The well-based platform consisted of laminate sheets and multiple layers of wax-printed chromatography paper. Solutions of KI and glucose placed into the well flowed through the device and reacted with the GOx@MOF species sandwiched between the paper layers realizing a yellow-brown color....
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Ilacas GC, Basa A, Nelms KJ, Sosa JD, Liu Y, Gomez FA Tags: Anal Chim Acta Source Type: research

Oxidation etching induced dual-signal response of carbon dots/silver nanoparticles system for ratiometric optical sensing of H2O2 and H2O2-related bioanalysis.
Abstract Ratiometric sensing suffers from less interference and can obtain more accurate results than single-signal assay. Here, a new ratiometric optical sensing strategy for H2O2 detection is developed by etching silver nanoparticles (AgNPs) to deactivate fluorescence resonance energy transfer (FRET) and reduce Rayleigh scattering based on a hyphenated technique of fluorescence and second-order Rayleigh scattering (SRS). The ratiometric detection of H2O2 is achieved through exploiting a hybrid system fabricated by fluorescent carbon dots and silver nanoparticles (CDs/AgNPs). In the CDs/AgNPs system, the fluoresc...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Liu SG, Mo S, Han L, Li N, Fan YZ, Li NB, Luo HQ Tags: Anal Chim Acta Source Type: research

A reusable electrochemical sensor for one-step biosensing in complex media using triplex-forming oligonucleotide coupled DNA nanostructure.
Abstract Here we report an electrochemical DNA (E-DNA) sensor to detect a variety of analytes by using a novel interfacial probe that rationally integrates triplex-forming oligonucleotide (TFO) into a tetrahedral DNA nanostructure (TDN). In the presence of analyte, the blocked TFO is released and subsequently binds the edge of TDN to form a triplex DNA structure, which confines the redox reporter to be in close proximity to the underlying electrode and enhances the electrochemical signal. Thanks to the unique design and property of the probe, the proposed sensor could efficiently suppress the background signal (fr...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Yang Y, Huang Y, Li C Tags: Anal Chim Acta Source Type: research

Unlocking the hidden talent of DNA: Unexpected catalytic activity for colorimetric assay of alkaline phosphatase.
Abstract Carboxylic acids have been efficiently used to activate H2O2 to form even more potent oxidant-peroxy acids through enzyme-catalyzed processes. By employing acetic acid as the activator, herein we report for the first time that cofactor-free DNA displays unexpected activity in H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under mild conditions. A series of 10-nt oligonucleotides were rationally designed with various combinations of double nucleotides including TG, AG, CG, TA and AC respectively, which demonstrates that the catalytic performance of DNA is highly dependent upon the sequence...
Source: Analytica Chimica Acta - February 22, 2019 Category: Chemistry Authors: Huang Q, He C, Zhang J, Li W, Fu Y Tags: Anal Chim Acta Source Type: research

Microfluidic and cross-linking methods for encapsulation of living cells and bacteria - A review.
Abstract Microencapsulation of living cells is a field that has been heavily investigated by many researchers over the past two decades. Numerous experimental setups have been developed to encapsulate living cells in microbeads using different microfluidic devices and materials. Previous studies have investigated different microfluidic devices and materials for use in cancer treatment, drug delivery, environmental remediation, food production, and cell culture contexts. Some of the current challenges to these setups are maintaining reasonable levels of cell viability, cell leaching, nutrient and oxygen diffusion, ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Alkayyali T, Cameron T, Haltli B, Kerr RG, Ahmadi A Tags: Anal Chim Acta Source Type: research

Multifunctional G-quadruplex-based fluorescence probe coupled with DNA-templated AgNCs for simultaneous detection of multiple DNAs and MicroRNAs.
Abstract A rapid, label-free, and multifunctional fluorescent probe for simultaneous detection of multiple targets was fabricated based on G-quadruplexes and DNA-templated silver nanoclusters (AgNCs). In this work, a probe with two capitated recognized regions was coupled with a locked G-quadruplex at the 5'-terminus and dark AgNC at the 3'-terminus. Upon the addition of the virus subtype H5N1 gene or microRNA-141, only the sequence of the G-quadruplex was released and bound with Thioflavin T (ThT) for a specific fluorescent response. On the contrary, with the presence of the influenza virus subtype H1N1 gene or m...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Han Y, Zhang F, Gong H, Cai C Tags: Anal Chim Acta Source Type: research

Fluorescence-enhanced p19 proteins-conjugated single quantum dot with multiplex antenna for one-step, specific and sensitive miRNAs detection.
Abstract Ideal methods for miRNA detection should be rapid and amplification-free in the mix-and-measure format. Here we report a novel FRET strategy based on fluorescence-enhanced p19 proteins-conjugated single quantum dot (QD) with multiplex antenna for one-step, specific and sensitive miRNAs quantitative analysis. It is simple in design and operation, and possesses high sensitivity and selectivity. In the strategy, RNA-binding viral p19 proteins-conjugated quantum dot (p19-QD) with high fluorescence and multiplex antenna was designed, and exploited for the capture recognition element and the donor. In the prese...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Ren X, Xue Q, Wen L, Li X, Wang H Tags: Anal Chim Acta Source Type: research

Ultrasensitive detection of telomerase activity in lung cancer cells with quencher-free molecular beacon-assisted quadratic signal amplification.
Abstract Telomerase is an important biomarker for cancer diagnosis and a valuable target for cancer therapy. Most of the reported telomerase assays suffer from the repeating thermal cycles, laborious protocols, expensive instruments and the limited sensitivity. To solve these issues, we develop a new telomerase assay based on telomerization-driven release of fluorescent 2-aminopurine. We designed a 2-aminopurine molecular beacon in which the fluorescence of 2-aminopurine is quenched due to stacking interaction effect without the use of extra quenchers. The presence of target telomerase can open the 2-aminopurine m...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Ma F, Wang TT, Jiang L, Zhang CY Tags: Anal Chim Acta Source Type: research

Low-cost fabrication of a paper-based microfluidic using a folded pattern paper.
Abstract Despite that microfluidic paper-based analytical devices (μPADs) provide effective analytical platforms for point-of-care diagnosis in resource-limited areas, it remains challenging to achieve simple and low-cost fabrication of μPADs. A novel method for fabrication of μPADs is developed in this study using a folded polydimethylsiloxane (PDMS)-coated paper mask with a specific pattern to form a sandwich structure with inserted chromatographic paper. PDMS penetrates the target paper from the front and the back sides, and then is cured in the target paper to form legible channels. This method for pr...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Xie L, Zi X, Zeng H, Sun J, Xu L, Chen S Tags: Anal Chim Acta Source Type: research

Ultrasensitive detection of avian influenza A (H7N9) virus using surface-enhanced Raman scattering-based lateral flow immunoassay strips.
In conclusion, the SERS-based LFIA strip proposed in this study shows tremendous potential to detect targets quickly and sensitively using an elegantly simple method. PMID: 30712559 [PubMed - in process] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Xiao M, Xie K, Dong X, Wang L, Huang C, Xu F, Xiao W, Jin M, Huang B, Tang Y Tags: Anal Chim Acta Source Type: research

A FRET-based ratiometric fluorescent probe for detection of intrinsically generated SO2 derivatives in mitochondria.
Abstract A mitochondria-targeted ratiometric fluorescent probe based on hemicyanine and pyrido[1,2-a]benzimidazole was presented. It shows high sensitivity and selectivity toward SO2 in pure water. The limit of detection (LOD) was as low as 26.7 nM, which is superior to most reported probes. Most importantly, the probe was successfully used for fluorescence imaging of endogenous bisulfite in mitochondria in Glioma cells. PMID: 30712560 [PubMed - in process] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Song G, Liu A, Jiang H, Ji R, Dong J, Ge Y Tags: Anal Chim Acta Source Type: research

Colorimetric copper ion sensing in solution phase and on paper substrate based on catalytic decomposition of S-nitrosothiol.
Abstract A S-nitrosothiol (RSNO) is used for highly selective and sensitive copper ion sensing for the first time. Cu(II) in the sample is reduced to Cu(I) by a low amount of thiols generated from hydrolysis of RSNO molecules or added thiols such as l-glutathione or l-cysteine. Cu(I) is able to trigger cleavage of the SNO bond, which converts colored RSNOs to colorless products. The dark green S-nitroso-N-acetylpenicillamine is used as an exemplary RSNO in this report. In the spectrophotometric test, the detection limit toward Cu(II) is 0.23 μM without added thiol reductants, and 0.08 and 0.06 μM in the ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Cui Y, Wang X, Zhang Q, Zhang H, Li H, Meyerhoff M Tags: Anal Chim Acta Source Type: research

Capillary electrophoresis with preparative isoelectric focusing preconcentration for sensitive determination of amphotericin B in  human blood serum.
This study demonstrates the potential of the off-line combination of preparative isoelectric focusing (IEF) with capillary isoelectric focusing (CIEF) or capillary zone electrophoresis (CZE) in the determination of AmB in human blood serum. The required value of the isoelectric point of AmB was determined to be 6.1 using the CIEF technique. Preparative IEF served as a pre-separation and concentration technique. The pH gradient was traced by colored low molecular pI markers. The collected fraction with AmB was easily processed and then analyzed by CIEF and CZE. Tens of picograms of AmB in human blood serum sample can be det...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Šalplachta J, Horká M, Šlais K Tags: Anal Chim Acta Source Type: research

Large-volume injection gas chromatography-vacuum ultraviolet spectroscopy for the qualitative and quantitative analysis of fatty acids in blood plasma.
Abstract Qualitative and quantitative determination of fatty acids in plasma is of extreme importance as these are indicators of metabolic diseases. In this work, a sensitive and rugged method for detecting and quantifying fatty acids (as fatty acid methyl ester derivatives, FAMEs) in blood plasma was developed. The use of large-volume injection (LVI) gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) for analysis of fatty acids in blood plasma allowed the injection of higher sample volumes to accommodate sufficient analyte on-column for necessary detection ranges with a run time of 45 min. Calibration ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Santos IC, Smuts J, Crawford ML, Grant RP, Schug KA Tags: Anal Chim Acta Source Type: research

Analytical strategy based on asymmetric flow field flow fractionation hyphenated to ICP-MS and complementary techniques to study gold nanoparticles transformations in cell culture medium.
os RDCR, Ríos Á Abstract An analytical methodology based on asymmetric flow field flow fractionation (AF4) hyphenated to inductively coupled plasma mass spectrometry (ICP-MS) has been developed to study gold nanoparticles (AuNPs) in cell culture medium (Dulbecco's Modified Eagle Medium, DMEM, containing 10% fetal bovine serum, FBS, and antibiotics) used for in vitro toxicological studies. AF4-ICP-MS separation of AuNPs was performed using a regenerated cellulose membrane (molecular weight cut-off, MWCO, of 10 kDa). The carrier composition and the AF4 separation program were optimized. Under th...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: López-Sanz S, Fariñas NR, Martín-Doimeadios RDCR, Ríos Á Tags: Anal Chim Acta Source Type: research

Absolute molar mass determination in mixed solvents. 1. Solving for the SEC/MALS/DRI "trivial" case.
Absolute molar mass determination in mixed solvents. 1. Solving for the SEC/MALS/DRI "trivial" case. Anal Chim Acta. 2019 Apr 11;1053:186-195 Authors: Striegel AM, Sinha P Abstract Size-exclusion chromatography (SEC) with on-line static light scattering, specifically multi-angle static light scattering (MALS), and differential refractometry (DRI) detection remains the premier method by which to determine absolute, calibrant-independent molar masses of polymers. The method is restricted to the use of either neat solvents or solvents with a small amount of additive. In mixed solvents, preferen...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Striegel AM, Sinha P Tags: Anal Chim Acta Source Type: research

Novel non-targeted analysis of perfluorinated compounds using fluorine-specific detection regardless of their ionisability (HPLC-ICPMS/MS-ESI-MS).
Abstract Although perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have been phased out, there is a plethora of per- or polyfluoroalkyl substances (PFAS) generated and only a small number of these compounds are currently being monitored in environmental and biological sample using molecular mass spectrometry (MS). Total fluorine determination has revealed that a substantial amount of fluorinated organic compounds has not been identified. Due to the small mass deficiency of fluorine, it is not an easy task to screen successfully all fluorinated compounds including those which are not easy ionis...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Jamari NLA, Dohmann JF, Raab A, Krupp EM, Feldmann J Tags: Anal Chim Acta Source Type: research

Photochemical multivariate curve resolution models for the investigation of photochromic systems under continuous irradiation.
kebusch C Abstract We propose a multivariate curve resolution approach for the investigation of photochromic systems using UV-Visible spectroscopy. The incorporation of photochemical hard-models as constraints in multivariate curve resolution alternating least squares (MCR-ALS) allows extracting reaction quantum yields in situations where a complete knowledge of the system is not available. We apply this approach to the study of the photochromism of CMTE (cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene) under continuous monochromatic irradiation. The mechanism, involving 3 species and 2 reversible reactio...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Devos O, Schröder H, Sliwa M, Placial JP, Neymeyr K, Métivier R, Ruckebusch C Tags: Anal Chim Acta Source Type: research

Facile fabrication of zwitterionic magnetic composites by one-step distillation-precipitation polymerization for highly specific enrichment of glycopeptides.
Abstract Hydrophilic interaction chromatography (HILIC) utilizing zwitterion-modified material as solid phase has attracted extensive attention for selective enrichment of glycopeptides. However, a tedious synthesis and low specificity for glycopeptides have restricted its application. Herein, a facile and effective approach was developed to synthesize a zwitterionic (ZIC) polymer-coated magnetic composites (denoted as Fe3O4@PMSA) with a zwitterion ((2-(methacryloyloxy)ethyl)-dimethyl-(3-sulfopropyl) ammonium hydroxide, MSA) via one-step distillation-precipitation polymerization (DPP). The well-designed composites...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Ji Y, Lv R, Song S, Huang J, Zhang L, Huang G, Li J, Ou J Tags: Anal Chim Acta Source Type: research

Spectrophotometric flow injection determination of dissolved titanium in seawater exploiting in-line nitrilotriacetic acid resin preconcentration and a long path length liquid waveguide capillary cell.
Abstract A sensitive spectrophotometric method for the determination of dissolved titanium (Ti) in seawater is developed. It involves in-line preconcentration and a long path length liquid waveguide capillary cell (LWCC). Nitrilotriacetic acid (NTA) resin is used to preconcentrate Ti from ∼25 mL seawater sample at pH 1.7, and elution is accomplished with 0.8 mol L-1 hydrochloride acid. The eluted Ti solution is buffered to pH 6.0 with 1.0 mol L-1 ammonium acetate and mixed with 1.5 mmol L-1 Tiron solution. The mixture is then injected into LWCC and measured by spectrophotometry at 420 nm. Befor...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Feng S, Wu J, Yuan D, Huang Y, Lin K, Chen Y Tags: Anal Chim Acta Source Type: research

On-line microfluidic immobilized-enzyme reactors: A new tool for characterizing synthetic polymers.
Abstract Biodegradable polymeric materials may eventually replace biostable materials for medical applications, including therapeutic devices, scaffolds for tissue engineering, and drug-delivery vehicles. To further develop such materials, a more fundamental understanding is necessary to correlate parameters including chemical-composition distribution within a macromolecular structure with the final properties of the material, including particle-size. A wide variety of analytical techniques have been applied for the characterization of polymer materials, including hyphenated techniques such as comprehensive two-di...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Wouters B, Pirok BWJ, Soulis D, Garmendia Perticarini RC, Fokker S, van den Hurk RS, Skolimowski M, Peters RAH, Schoenmakers PJ Tags: Anal Chim Acta Source Type: research

Encoded particle microfluidic platform for rapid multiplexed screening and characterization of aptamers against influenza A  nucleoprotein.
In this study, we assessed a new microfluidic platform, namely Evalution™, as a rapid and high throughput aptamer characterization platform. To do this, we first selected aptamers against influenza A nucleoprotein (infA NP) by performing magnetic bead-based SELEX. The selected aptamer candidates were subsequently screened using Evalution™ for their binding kinetics and specificity towards infA NP. All aptamers showed dissociation constants (KD) in the low nanomolar range (from 13 to 41 nM), and differential binding behavior towards control proteins, such as BSA and influenza B nucleoprotein (infB NP). Among 5...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Leblebici P, Leirs K, Spasic D, Lammertyn J Tags: Anal Chim Acta Source Type: research

Visualization of endogenous hydrogen sulfide in living cells based on Au nanorods@silica enhanced fluorescence.
Abstract Hydrogen sulfide as a gas indicator molecule plays an important role in various human physiological processes. However, due to the high volatility and diffusivity of H2S in biological systems, it is very difficult to implement a precise assay for H2S detection. Compared with the destructive instrumental methods, assays based on fluorescence probes provide noninvasive and real-time detections of H2S in living cells. In this work, we presented a fluorescent nanoprobe based on dye-functionalized Au nanorods (NRs)@silica for sensitive and selective detection of H2S in vitro and living cells. With the met...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Luo Y, Song Y, Zhu C, Li S, Xian M, Wai CM, Lin Y, Du D Tags: Anal Chim Acta Source Type: research

In situ formation of fluorescent polydopamine catalyzed by peroxidase-mimicking FeCo-LDH for pyrophosphate ion and pyrophosphatase activity detection.
Abstract As pyrophosphate ion (PPi) and pyrophosphatase (PPase) play crucial roles in the pathological process of arthritis, determination of PPi and PPase in biological fluids turns to be of great importance for clinical diagnosis and therapy of arthritic diseases. In this work, we proposed a new fluorescent assay for PPi and PPase activity detection based on the competitive coordination chemistry of Fe3+ between PPi and an in situ formed fluorescent polydopamine (PDA). FeCo layered double hydroxide (FeCo-LDH) was explored as a peroxidase mimic to facilitate the in situ formation of fluorescent PDA from dopamine ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Xu X, Zou X, Wu S, Wang L, Niu X, Li X, Pan J, Zhao H, Lan M Tags: Anal Chim Acta Source Type: research

A novel ELISA for the detection of active form of plasminogen activator inhibitor-1 based on a highly specific trapping agent.
Abstract Plasminogen activator inhibitor-1 (PAI-1) is a labile molecule that exists in four different forms: active, latent, cleaved and target bound form. Although there have been many methods to measure the total PAI-1, the measurement of active form of PAI-1 antigen is still challenging. Here we developed a novel ELISA to detect the active form of PAI-1 based on a highly specific PAI-1 capturing agent which binds to active PAI-1 with high affinity. We also used a highly stable PAI-1 mutant as an assay calibrator to enhance the method's reproducibility. This ELISA has the advantage of measuring both the antigen ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Shang L, Xue G, Gong L, Zhang Y, Peng S, Yuan C, Huang M Tags: Anal Chim Acta Source Type: research

Analytical applications and physicochemical properties of ionic liquid-based hybrid materials: A review.
Abstract Ionic liquids with their unique properties found so far numerous analytical applications. Among them ionic liquids immobilized on the surface or within the pores of a solid support were successfully utilized in extraction techniques dedicated to preconcentration of the analytes from food, environmental and biological samples. In this review we focus on comprehensive summarizing of available literature data on the examples of ionic liquid-based hybrid materials implementation in selected analytical extraction techniques, namely solid-phase extraction, solid-phase microextraction, hollow-fiber solid-phase m...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Yavir K, Marcinkowski Ł, Marcinkowska R, Namieśnik J, Kloskowski A Tags: Anal Chim Acta Source Type: research

Mass spectrometric imaging reveals photocatalytic degradation intermediates of aromatic organochlorines resulting from interfacial photoelectron transfer and hydroxyl radical abstraction on semiconductor nanoparticles.
Abstract Organochlorines are highly persistent and toxic contaminants that are widely distributed and accumulated in various aquatic or soil environments as well as food chains. Heterogeneous photocatalytic degradation of such pollutants by using semiconductor nanoparticles has been recognized as one of the effective purification ways. Understanding of degradation mechanisms and designing of highly efficient semiconductor nanoparticles require structural identification of various degradation intermediates that are difficult to achieve with current spectroscopic techniques. Herein a mass spectrometric approach was ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Tang X, Qi Y, Zhang W, Zhang J, Jiang R, Zhong H Tags: Anal Chim Acta Source Type: research

Use of MALDI-MS with solid-state hydrogen deuterium exchange for semi-automated assessment of peptide and protein physical stability in lyophilized solids.
Abstract Biological therapeutics are established as major contributors to the pharmaceutical pipeline. Many of these biological drugs are lyophilized to preserve their conformation and reduce decomposition during storage and shipping. Therefore, understanding and controlling the effects of lyophilization on protein higher order structure is critical for commercialization of biologics. Hydrogen Deuterium Exchange Mass Spectrometry (HDX-MS) is a well-established technique for studying protein higher order structure. Previous publications have demonstrated a solid state HDX (ssHDX) method for labeling formulated, lyo...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Kabaria SR, Mangion I, Makarov AA, Pirrone GF Tags: Anal Chim Acta Source Type: research

Smartphone-based apparatus for measuring upconversion luminescence lifetimes.
Abstract Luminescence lifetime detection plays an important role in time-resolved detection and research. However, the traditional instruments always require expensive detectors such as time-correlated single photon counter or streak camera. Herein, a low-cost and miniaturized apparatus for measuring upconversion luminescence lifetimes was developed by using a smartphone equipped with a 980 nm CW laser and a motor. When the motor was driving the sample circling at a high linear velocity, the excited sample would emit a luminescence arc, which could be photographed by the phone camera. The rotating rate could be ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Zhu Z Tags: Anal Chim Acta Source Type: research

Double-integrated mimic enzymes for the visual screening of Microcystin-LR: Copper hydroxide nanozyme and G-quadruplex/hemin DNAzyme.
Abstract Recently, mimic enzymes have obtained particular interest by their high activity, stability, and biocompatibility. In this work, by coupling copper hydroxide nanozyme and G-quadruplex/hemin DNAzyme to form a double-integrated mimic enzyme, a visual, sensitive and selective immunosensor was established to detect microcystin-LR (MC-LR). In this immunoassay, the microplates were modified with core-shell silica/nickel silicate as the substrate to capture MC-LR antigens. Then, Cu(OH)2 nanocages with fine regulation were used as the label to capture the secondary antibody for immunoreaction and the DNA primer f...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Liu W, Gan C, Chang W, Qileng A, Lei H, Liu Y Tags: Anal Chim Acta Source Type: research

A dual-channel probe with green and near-infrared fluorescence changes for in  vitro and in vivo detection of peroxynitrite.
In this study, a coumarin-semirhodamine hybrid based dual-channel fluorescent probe was developed for detection of peroxynitrite. This probe works well in nearly pure aqueous solution and displays a rapid, highly sensitive and selective response for peroxynitrite at two different emission wavelengths (700 and 515 nm, respectively), along with distinct color and green to near-infrared fluorescence changes. The fluorescent intensity ratio at 700 and 515 nm increases linearly with the concentration of peroxynitrite from 0 to 50 μM, and the detection limit is estimated to be 59 nM. Moreover, bioimaging of exogenous ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Feng S, Liu D, Feng G Tags: Anal Chim Acta Source Type: research

Mustard seeds derived fluorescent carbon quantum dots and their peroxidase-like activity for colorimetric detection of H2O2 and ascorbic acid in a real sample.
Abstract Herein, we were synthesized fluorescent carbon quantum dots via facile one-step hydrothermal treatment of mustard seeds (M-CQDs). It showed excellent optical property with fluorescent quantum yield 4.6%. The as-prepared M-CQDs exhibited peroxidase-like mimetic activity and catalyzed the oxidation of chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue color reaction mixture with the prominent peak at 652 nm. Furthermore, the peroxidase-like catalytic performance of M-CQDs followed the steady-state kinetics behavior and exhibited similar catalytic activity ...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Chandra S, Singh VK, Yadav PK, Bano D, Kumar V, Pandey VK, Talat M, Hasan SH Tags: Anal Chim Acta Source Type: research

Rapid and specific detection of Salmonella infections using chemically modified nucleic acid probes.
ez FJ Abstract Salmonella is a leading source of bacterial foodborne illness in humans, causing gastroenteritis outbreaks with bacteraemia occurrences that can lead to clinical complications and death. Eggs, poultry and pig products are considered as the main carriers of the pathogenic Salmonella for humans. To prevent this relevant zoonosis, key changes in food safety regulations were undertaken to improve controls in the food production chain. Despite these measures, large outbreaks of salmonellosis were reported worldwide in the last decade. Thus, new strategies for Salmonella detection are a priority for both,...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Machado I, Garrido V, Hernandez LI, Botero J, Bastida N, San-Roman B, Grilló MJ, Hernandez FJ Tags: Anal Chim Acta Source Type: research

Label-free fluorescent discrimination and detection of epinephrine and dopamine based on bioinspired in situ copolymers and excitation wavelength switch.
In this study, PEI aqueous solution medium initiates the auto-oxidization of Ep and DA and the bioinspired copolymerization. These resultant copolymers emit yellow-green fluorescence color with a fluorescence emission maximum at 515 nm. Interestingly, these fluorescent copolymers exhibit distinct different excitation spectra, although Ep and DA are structurally very similar. PDA-PEI exhibits only one excitation peak at 385 nm, and PEp-PEI shows dual-excitation mode with two significant excitation peaks at 328 nm and 405 nm, respectively. MEp+DA also shows dual-excitation mode with two excitation peaks at 330 nm a...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Zhang Y, Ren W, Fan YZ, Dong JX, Zhang H, Luo HQ, Li NB Tags: Anal Chim Acta Source Type: research

Determination and elimination of hazardous pollutants by exploitation of a Prussian blue nanoparticles-graphene oxide composite.
Abstract The exploitation of desired materials with specific properties for water remediation has become an irresistible trend. Generally, materials favorable to the elimination of hazardous contaminants are always beneficial to the detection of these compounds. Nevertheless, few researches combined these two procedures into a treating line. Therefore, a Prussian blue nanoparticles-doped graphene oxide (PBGO) composite was successfully synthesized and prepared as a solid-phase microextraction (SPME) coating for pollutant detection and a three-dimensional (3D) aerogel for contaminant removal in this study. Owing to...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Liu S, Pan G, Yang H, Cai Z, Zhu F, Ouyang G Tags: Anal Chim Acta Source Type: research

Developed magnetic multiporous 3D N-Co@C/HCF as efficient sorbent for the extraction of five trace phthalate esters.
Abstract A three-dimensional (3D) magnetic porous N-Co@carbon dodecahedron/hierarchical carbon framework (3D N-Co@C/HCF) hybrid has been successfully synthesized by integration of the ZIF-67 into HCF and then calcination under an inert gas (N2). 3D N-Co@C/HCF as magnetic sorbent show good extraction ability for phthalate esters (PAEs: dibutyl phthalate (DBP), dimethyl phthalate (DMP), dicyclohexyl phthalate (DCHP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP)). This is attributed not only to the abundant adsorption sites (due to the presence of large specific surface area) and the extremely strong π-co...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Wang Y, Tong Y, Xu X, Zhang L Tags: Anal Chim Acta Source Type: research

Analysis of charged acrylic particles by on-line comprehensive two-dimensional liquid chromatography and automated data-processing.
Abstract A thorough understanding of particle formation and polymer growth during emulsion polymerization is indispensable for the development of particles and products with very specific properties. This has created a demand for the detailed characterization of various properties and property distributions - and the relation between these. A method is described that enables comprehensive, simultaneous determination of the size distribution of nanoparticles and the molecular-weight distribution of the constituting polymers as a function of the particle size. The result is a complete two-dimensional distribution th...
Source: Analytica Chimica Acta - February 5, 2019 Category: Chemistry Authors: Pirok BWJ, Abdulhussain N, Brooijmans T, Nabuurs T, de Bont J, Schellekens MAJ, Peters RAH, Schoenmakers PJ Tags: Anal Chim Acta Source Type: research