On the competition between mixing rate and uniformity in a coaxial hydrodynamic focusing mixer.
Abstract Fast microfluidic mixers for use with line-of-sight integrating detection schemes pose unique challenges. Such detectors typically cannot discriminate signal from slow moving (e.g. near internal walls) and fast-moving portions of the fluid stream. This convolves reaction rate dynamics with fluid flow residence time dynamics. Further, the small cross sections of typical three-dimensional hydrodynamic focusing devices lead to lower detection signals. The current study focuses on achieving both small time scales of mixing and homogenous residence times. This is achieved by injecting sample through a center c...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Huyke DA, Ramachandran A, Oyarzun DI, Kroll T, DePonte DP, Santiago JG Tags: Anal Chim Acta Source Type: research

A multifaceted investigation on the effect of vacuum on the headspace solid-phase microextraction of extra-virgin olive oil.
Abstract Headspace solid-phase microextraction (HS-SPME) is an easy, effective, and selective technique for the extraction of volatiles and semi-volatiles compounds. For the latter, longer equilibration times are needed, which are typically shortened by applying agitation or heating the sample. A less explored way to improve the extraction kinetics of analytes with a low-affinity for the headspace is to sample under vacuum conditions. The methodology that evolved from this approach was termed "vacuum-assisted HS-SPME" (Vac-HS-SPME) and was mainly used for water- and solid-based samples. The aim of this w...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Mascrez S, Psillakis E, Purcaro G Tags: Anal Chim Acta Source Type: research

Miniaturized liquid chromatography focusing on analytical columns and mass spectrometry: A review.
cedil;as FM Abstract The technological advances achieved over the last decades boosted the development of suitable benchtop platforms to work at miniaturized liquid chromatography scale (capillary and nano-LC). Under the right conditions, miniaturized LC can offer higher analysis efficiency resulting in superior chromatographic resolution and overall sensitivity than conventional LC. Among the main advantages are the reduced reagents and sample requirement, the decreasing on analytical column dimensions, and consequently flow rates and the easer coupling to mass spectrometry. This review describes fundamental aspe...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Vasconcelos Soares Maciel E, de Toffoli AL, Sobieski E, Domingues Nazário CE, Lanças FM Tags: Anal Chim Acta Source Type: research

Paper-based colorimetric biosensor of blood alcohol with in-situ headspace separation of ethanol from whole blood.
Abstract This work presents a novel development that exploits the concept of in-situ gas-separation together with a specific enzymatic colorimetric detection to produce a portable biosensor called "Blood Alcohol Micro-pad" for direct quantitation of ethanol in whole blood. The thin square device (25 mm × 25 mm × 1.8 mm) comprises two layers of patterned filter paper held together with a double-sided mounting tape with an 8-mm circular hole (the headspace). In operation, the reagent is deposited on one layer and covered with sticky tape. Then 8 μL of ...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Thepchuay Y, Sonsa-Ard T, Ratanawimarnwong N, Auparakkitanon S, Sitanurak J, Nacapricha D Tags: Anal Chim Acta Source Type: research

Rapid determination of isoflavones and other bioactive compounds in soybean using SWATH-MS.
In this study, a high-throughput SWATH-MS method for the determination of 12 isoflavones in soybeans was established. Furthermore, amino acids, saponins can be semi-quantitated from the same SWATH-MS data. Combination of targeted quantification and untargeted profiling with SWATH, all bioactive compounds were analyzed within 5 min in 10 min run time, and the method had good linear regression with r2 > 0.99. The precisions (RSD %) of the intra-day and inter-day analyses ranged from 2.11% to 18.7%, and the accuracies (RE%) ranged from -14.39% to 17.48%. The matrix effect ranged from 88.66% to 114....
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Chien HJ, Wang CS, Chen YH, Toh JT, Zheng YF, Hong XG, Lin HY, Lai CC Tags: Anal Chim Acta Source Type: research

A ''naked-eye'' colorimetric and ratiometric fluorescence probe for uric acid based on Ti3C2 MXene quantum dots.
Abstract In this work, we developed a ''naked-eye'' colorimetric and ratiometric fluorescence probe for a very important biomarker of uric acid (UA). The method was based on the oxidation of UA by uricase to allantoin and hydrogen peroxide, and then o-Phenylenediamine (OPD) was oxidized to the yellow-colored 2,3-diaminophenazine (oxOPD) in the presence of horseradish peroxidase (HRP) and hydrogen peroxide. The fluorescence emission of glutathione functionalized Ti3C2 MQDs (GSH-Ti3C2 MQDs) centered at 430 nm overlaps with the UV absorption of oxOPD at 425 nm to a large extent, which facilitates fluorescen...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Liu M, He Y, Zhou J, Ge Y, Zhou J, Song G Tags: Anal Chim Acta Source Type: research

Model-based correction algorithm for Fourier Transform infrared microscopy measurements of complex tissue-substrate systems.
Abstract Model-based algorithms have recently attracted much attention for data pre-processing in tissue mapping and imaging by Fourier transform infrared micro-spectroscopy (FTIR). Their versatility, robustness and computational performance enabled the improvement of spectral quality by mitigating the impact of scattering and fringing in FTIR spectra of chemically homogeneous biological systems. However, to date, no comprehensive algorithm has been optimized and automated for large-area FTIR imaging of histologically complex tissue samples. Herein, for the first time, we propose a unique, integrated and fully-aut...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Surowka AD, Birarda G, Szczerbowska-Boruchowska M, Cestelli-Guidi M, Ziomber-Lisiak A, Vaccari L Tags: Anal Chim Acta Source Type: research

Responsive nanosensor for ratiometric luminescence detection of hydrogen sulfide in inflammatory cancer cells.
This study provides a powerful approach for detection of highly reactive and unstable H2S biomolecules in live systems. PMID: 32081180 [PubMed - in process] (Source: Analytica Chimica Acta)
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Liu J, Duan C, Zhang W, Ta HT, Yuan J, Zhang R, Xu ZP Tags: Anal Chim Acta Source Type: research

A tri-functional probe mediated exponential amplification strategy for highly sensitive detection of Dnmt1 and UDG activities at single-cell level.
Abstract Multiplex DNA methylation and glycosylation are ubiquitous in the human body to ensure the normal function and stability of the genome. The methyltransferases and glycosylases rely on varied enzymes with different action mechanism, which still remain challenges for multiple detection. Herein, we developed a tri-functional dsDNA probe mediated exponential amplification strategy for sensitive detection of human DNA (cytosine-5) methyltransferase 1 (Dnmt1) and uracil-DNA glycosylase (UDG) activities. The tri-functional dsDNA probe was rationally designed with M-DNA and U-DNA. M-DNA contains the 5'-GCmGCGC-3'...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Fan L, Peng Y, Ning B, Wei H, Gao Z, Bai J, Guo L Tags: Anal Chim Acta Source Type: research

Dual-site fluorescent probe for multi-response detection of ClO- and H2O2 and bio-imaging.
Abstract Hypochlorite (ClO-) and hydrogen peroxide (H2O2) commonly coexist in organism and are involved in the same physiological and pathological processes. So it is of great importance to develop fluorescent probes to detect both simultaneously. Herein, we reported the first dual-site fluorescent probe (Geisha-1) for the quantitative detection of ClO- and H2O2. This probe is constructed by chemically grafting N,N-dimethylthiocarbamate and borate to a fluorescence resonance energy transfer (FRET) platform. As a result, Geisha-1 not only presents three different responses to ClO-, H2O2, and ClO- + H2O2 (...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Du Y, Wang B, Jin D, Li M, Li Y, Yan X, Zhou X, Chen L Tags: Anal Chim Acta Source Type: research

Room temperature phosphorescent determination of aflatoxins in fish feed based on molecularly imprinted polymer - Mn-doped ZnS quantum dots.
-Piñeiro A Abstract Possibilities of room temperature spectrometry based on Mn-doped ZnS quantum dots coated with a molecularly imprinted polymer based nanosensor have been explored for the sensitive and selective determination of aflatoxins. Synthesized polymeric nanoparticles exhibit intense room temperature phosphorescence (total decay time of 0.004 s) and aflatoxins quench the room temperature phosphorescence when interact with the recognition cavities of the molecularly imprinted polymer attached to the phosphorescent quantum dots. Room temperature phosphorescence was recorded by scanning from 520...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Madurangika Jayasinghe GDT, Domínguez-González R, Bermejo-Barrera P, Moreda-Piñeiro A Tags: Anal Chim Acta Source Type: research

Selective detection of pyrophosphate anion by zinc ensemble of C3-symmetric triaminoguanidine-pyrrole conjugate and its biosensing applications.
Abstract A new-fangled C3-symmetric triaminoguanidine-pyrrole conjugate has been constructed and utilized for sensing applications. The probe selectively detects zinc ions (Zn2+) by colorimetric as well as turn-on fluorescent manner. Further, the in-situ formed zinc ensemble displays turn-off fluorescence response towards the pyrophosphate anion (PPi) via displacement approach. Emissive off-on-off sensing characteristics of the probe has been successfully exploited to construct the INHIBIT logic gate, coding/decoding of messages and in vivo imaging of Zn2+/PPi in zebrafish larvae. Further, PPi detection chara...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Tharmalingam B, Mathivanan M, Mani KS, Kaminsky W, Raghunath A, Jothi M, Perumal E, Murugesapandian B Tags: Anal Chim Acta Source Type: research

A mitochondria-targeting nitroreductase fluorescent probe with large Stokes shift and long-wavelength emission for imaging hypoxic status in tumor cells.
Abstract Development of a mitochondria-targeting fluorescent probe with large Stokes shift and long-wavelength emission was benefit for accurate detection of hypoxic status, which was known as a major factor of the tumor physiology and influence important pathological processes. However, an efficient optical approach for simultaneously achieving such merits was still lacking. In this work, a turn-on fluorescence probe (HBT-NP) was designed to assess the hypoxic condition of tumor cells by detecting nitroreductase (NTR). Probe HBT-NP was constructed by conjugating 4-nitrobenzyl moiety as reaction site for NTR to 2-...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Yang Q, Wang S, Li D, Yuan J, Xu J, Shao S Tags: Anal Chim Acta Source Type: research

Ratiometric fluorescence sensor based on carbon dots as internal reference signal and T7 exonuclease-assisted signal amplification strategy for microRNA-21 detection.
Abstract The expression level of miRNA-21 is closely related to the occurrence and development of cancer, especially in gastrointestinal cancer. Monitoring miRNA-21 has clinical application in the diagnosis and evaluation of gastrointestinal cancer. A turn-on ratiometric fluorescence bioassay based on the T7 exonuclease-mediated cyclic enzymatic amplification method was developed for miRNA-21 determination by using carbon dots (CDs) and FAM-labeled ssDNA as the signal source. CDs demonstrated the triple functions of built-in internal fluorescence, probe carrier, and quencher in this strategy. In the absence of miR...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Wang Z, Xue Z, Hao X, Miao C, Zhang J, Zheng Y, Zheng Z, Lin X, Weng S Tags: Anal Chim Acta Source Type: research

Recent advances in the application of layered double hydroxides in analytical chemistry: A review.
Abstract In recent years, layered double hydroxides (LDHs) have garnered a lot of attention in analytical chemistry, due to their advantages such as relatively simple synthesis, low cost, possession of large specific surface area and high catalytic activity, and biocompatibility. The most common applications of LDH in analytical chemistry such as sorbents in sample extraction, electrode materials in electrochemical sensing and color indicators in colorimetric detection have been well reported. Generally, the LDHs are prepared as composites with nanomaterials, or constructed with specific three-dimensional structur...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Tang S, Yao Y, Chen T, Kong D, Shen W, Lee HK Tags: Anal Chim Acta Source Type: research

A new approach for IR spectra matching using normalized local change.
Abstract Spectra matching is widely used in various applications including the search for a spectrum of an unknown compound in an existing spectral database and quality control by means of comparing the spectra of products with standards. In this article, we present a new approach for calculating the similarities of Fourier-transform infrared (FTIR) spectra of organic compounds. Our method, named normalized local change (NLC) approach, incrementally calculates the spectral similarity based on the local spectral shapes. This allows for reducing the bias on the uneven weighing of large and/or broader peaks. In addit...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Ellis JD, Iqbal R, Yoshimatsu K Tags: Anal Chim Acta Source Type: research

Disposable glassy carbon stencil printed electrodes for trace detection of cadmium and lead.
Abstract Cadmium (Cd) and lead (Pb) pollution is a significant environmental and human health concern, and methods to detect Cd and Pb on site are valuable. Stencil-printed carbon electrodes (SPCEs) are an attractive electrode material for point-of-care (POC) applications due to their low cost, ease of fabrication, disposability and portability. At present, SPCEs are exclusively formulated from graphitic carbon powder and conductive carbon ink. However, graphitic carbon SPCEs are not ideal for heavy metal sensing due to the heterogeneity of graphitic SPCE surfaces. Moreover, SPCEs typically require extensive modif...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Kava AA, Beardsley C, Hofstetter J, Henry CS Tags: Anal Chim Acta Source Type: research

Signal-off/on electrogenerated chemiluminescence deoxyribosensors for assay of early lung cancer biomarker (NAP2) based on target-caused DNA charge transfer.
Abstract Two novel electrochemiluminescence (ECL) deoxyribosensors are designed for assay of early lung cancer biomarker (NAP2) using the DNA three-way junction (DNA-TWJ) inserted NAP2 binding aptamer between two double-helical stems and labeled with ruthenium (II) complex (Ru) (NBAT-Ru) taken as molecular recognition element. The signal-off ECL deoxyribosensor was fabricated by covalently coupling the 5'-NH2-(CH2)6-NBAT-Ru to glassy carbon electrode surface modified with 4-aminobenzoic acid (4-ABA). After combining NAP2 and NBAT-Ru, the changed conformation of NBAT-Ru altered the distance between Ru complex and e...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Chen Y, Sun L, Qiao X, Zhang Y, Li Y, Ma F Tags: Anal Chim Acta Source Type: research

Determination of salivary uric acid by using poly(3,4-ethylenedioxythipohene) and graphene oxide in a disposable paper-based analytical device.
Abstract We developed a paper-based analytical device based on the electropolymerization of poly (3,4-ethylenedioxythipohene) (PEDOT) and graphene oxide (GO) composites on the ITO substrate for the detection of uric acid (UA) in authentic human saliva. Scanning electron microscopy, UV-vis spectrum and X-ray diffraction confirmed the formation of porous PEDOT combined with GO film during the electropolymerization process. The nanocomposite based sensor showed an enhanced electrocatalytic activity toward UA with high sensitivity and stability. We demonstrate that UA can be directly detected in undiluted saliva using...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Huang X, Shi W, Li J, Bao N, Yu C, Gu H Tags: Anal Chim Acta Source Type: research

Graphitic carbon nitride/graphene oxide(g-C3N4/GO) nanocomposites covalently linked with ferrocene containing dendrimer for ultrasensitive detection of pesticide.
We report herein the design of a novel electrochemical sensing strategy for sensitive detection of pesticide based on graphitic carbon nitride (g-C3N4)/graphene oxide(GO) nanocomposite covalently bound to a ferrocene containing dendrimer(Fc-TED). The g-C3N4 with sufficient N atoms for providing lone pairs of electrons to an electron acceptor so as to enhance the adsorption towards organic molecules. The Fc-TED dendrimers with the native redox signaling center (Fe3+/Fe2+) can increase the electron transition of g-C3N4 from valence to conduction band. While GO can accelerate the electron transfer from g-C3N4 surface and Fc-T...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Xiao F, Li H, Yan X, Yan L, Zhang X, Wang M, Qian C, Wang Y Tags: Anal Chim Acta Source Type: research

A double-recognized aptamer-molecularly imprinted monolithic column for high-specificity recognition of ochratoxin A.
In this study, a double-recognized aptamer-molecularly imprinted monolithic column (Apt-MIP monolithic column) was prepared by introducing both aptamer and MIP to reduce non-specific adsorption. Its preparation parameters such as the time of photo-initiation, the dosage of photo-initiator and the concentration of aptamer were investigated in detail. The recovery ratios of ochratoxin A (OTA) to ochratoxin B (OTB) on Apt-MIP monolithic column, Apt monolithic column and MIP monolithic column were 116.1, 40.8 and 69, respectively. Even if the concentration of OTB was 10 times that of OTA, the recovery of OTB was only about 2.9...
Source: Analytica Chimica Acta - February 23, 2020 Category: Chemistry Authors: Lyu H, Sun H, Zhu Y, Wang J, Xie Z, Li J Tags: Anal Chim Acta Source Type: research

Integrated microfluidic chip for on-line proteome analysis with combination of denaturing and rapid digestion of protein.
Abstract A microfluidic platform based on the integration of denaturation and online immobilized enzyme reactor (IMER) digestion for protein pretreatment was first developed on a glass chip. The design of three inlet channels and two groups of snake channel in glass chip can allow the protein solution, the reducing reagent and the alkylating agent to be simultaneously injected into the chip channel and ensured the reaction solution on-line efficient mixing and sufficient reacting. By thiol-ene click chemistry, the capillary-based and glass chip-based trypsin IMER on the surface of poly(trimethylolpropane trimethac...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Wei Z, Fan P, Jiao Y, Wang Y, Huang Y, Liu Z Tags: Anal Chim Acta Source Type: research

Key significance of DNA-target size in lateral flow assay coupled with recombinase polymerase amplification.
Abstract The combination of isothermal nucleic acid amplification and lateral flow assay (LFA) provides highly sensitive non-laboratory ("point-of-care") detection. The aim of this study is to investigate the recognition on lateral flow membranes of DNA targets with different lengths as products of recombinase polymerase amplification (RPA). We produced double-stranded DNA with lengths of 50, 100, 150, 200, and 300 bp. Each DNA target was functionalized with biotin and fluorescein (FAM). Kinetic and equilibrium constants of the interaction of FAM at the 5'-end of DNA with anti-FAM antibodies did not depend...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Safenkova IV, Ivanov AV, Slutskaya ES, Samokhvalov AV, Zherdev AV, Dzantiev BB Tags: Anal Chim Acta Source Type: research

Magnetic restricted-access carbon nanotubes for dispersive solid phase extraction of organophosphates pesticides from bovine milk samples.
Abstract Magnetic restricted-access carbon nanotubes (M-RACNTs) were synthesised and used for dispersive solid phase extraction of organophosphates (chlorpyriphos, malathion, disulfoton, pirimiphos) from commercial bovine raw milk samples. Due to their magnetic susceptibility, M-RACNTs were easily separated from the samples/solvents using a neodymium magnet, and the extracted organophosphates were analysed by gas chromatography-mass spectrometry. The protein exclusion capacity was about 100%. Kinetic and isotherm data (for M-RACNTs - malathion interaction) were adequately adjusted to the pseudo-second order and Si...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Campos do Lago A, da Silva Cavalcanti MH, Rosa MA, Silveira AT, Teixeira Tarley CR, Figueiredo EC Tags: Anal Chim Acta Source Type: research

A palindromic-based strategy for colorimetric detection of HIV-1 nucleic acid: Single-component assembly of gold nanoparticle-core spherical nucleic acids.
Abstract Gold nanoparticle-core spherical nucleic acids (AuNP core-SNAs), by virtue of the programmable nature of oligonucleotides, have yielded access to the innovative strategies for targeted biodiagnostics. Here, DNA-directed self-assembly of AuNP core-SNAs has been used to design a colorimetric method to sense HIV-1 viral nucleic acid. This strategy utilizes an oligonucleotide with sequence of 5'-untranslated region (5' UTR) of the HIV-1 RNA genome anchored on the surface of AuNPs and a complementary linker strand with a palindromic sequence tail. In the absence of HIV-1 target nucleic acid the complementary l...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Karami A, Hasani M Tags: Anal Chim Acta Source Type: research

Absolute quantitation of high abundant Fc-glycopeptides from human serum IgG-1.
In this study, eleven high abundant IgG-1 Fc-glycopeptides with definite peptide sequences and glycoforms were purified from commercial IgG protein by using two-dimensional hydrophilic interaction liquid chromatographic system. Based on the acquired glycopeptide standards, an absolute quantitation strategy was developed to determine the concentrations of 11 target IgG-1 glycopeptides from pooled human sera. A wide range of Fc-glycopeptide concentrations from 0.60 to 17.61 nmol mL-1 was achieved with excellent accuracy and reproducibility from pooled human sera IgG-1. Compared to conventional relative quantitation...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Cao C, Yu L, Fu D, Yuan J, Liang X Tags: Anal Chim Acta Source Type: research

Micelle-dominated distribution strategy for non-matrix matched calibration without an internal standard: "Extract-and-shoot" approach for analyzing hydrophilic targets in blood and cell samples.
Micelle-dominated distribution strategy for non-matrix matched calibration without an internal standard: "Extract-and-shoot" approach for analyzing hydrophilic targets in blood and cell samples. Anal Chim Acta. 2020 Mar 15;1102:24-35 Authors: Yuan J, Li A, Chen T, Du J, Ma A, Pan J Abstract The analysis of trace hydrophilic targets in complex aqueous-rich matrices is considerably challenging, generally requiring matrix-matched calibration, internal standard, or time-and-labor-intensive sample preparation. To address this analytical bottleneck, a non-matrix-matched calibration strategy withou...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Yuan J, Li A, Chen T, Du J, Ma A, Pan J Tags: Anal Chim Acta Source Type: research

Development and evaluation of the iron oxide-hydroxide based resin gel for the diffusive gradient in thin films technique.
te; A, Hedbávný J, Grmela J Abstract An ion-exchange resin Lewatit FO 36 was used for the preparation of a new resin gel for the diffusive gradient in thin films technique (DGT). The DGT method was optimized for the accumulation of four bioavailable arsenic species (AsIII, AsV, monomethylarsonic acid, dimethylarsinic acid) in the aquatic environment. The total sorption capacity of Lewatit FO 36 resin gel was 535 μg As disc-1. The microwave-assisted extraction in the presence of NaCl (10 g L-1) and NaOH (10 g L-1) was used for the isolation of arsenic species from the Lewat...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Smolíková V, Pelcová P, Ridošková A, Hedbávný J, Grmela J Tags: Anal Chim Acta Source Type: research

Track-etched membrane-based dual-electrode coulometric detector for microbore/capillary high-performance liquid chromatography.
Abstract The electrochemical flow cell containing track-etched microporous membrane electrodes was applied to a dual-electrode coulometric detector for microbore/capillary HPLC with a small injection volume and low eluent flow rate. The proposed flow cell with a 0.1-mm diameter inlet channel gave a detection volume of 0.08 nL per electrode, which was determined by the eluent flow through the electrode. For the dual-electrode detector, the calculated volume was 0.24 nL. The efficiency of electrooxidation of l-ascorbic acid increased as the flow rate decreased and was close to 100% when the flow rate was b...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Mizuguchi H, Nishimori D, Kuwabara T, Takeuchi M, Iiyama M, Takayanagi T Tags: Anal Chim Acta Source Type: research

Evaluation of chemical cross-linkers for in-depth structural analysis of G protein-coupled receptors through cross-linking mass spectrometry.
In this study, we systematically evaluated the impact of five conventional cross-linkers targeting Lys, Asp and Glu, and two Arg-reactive cross-linkers on the structural and functional integrity of two G protein-coupled receptors (GPCRs). Perturbation of the receptor structure and ligand-binding activity was observed, depending on the receptor and cross-linking conditions. In particular, our study demonstrated that the concentrations of PDH and KArGO need to be fine-tuned in order to minimize the structural and functional disturbance of specific GPCRs. A set of amenable cross-linkers was selected to acquire the most compre...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Xia L, Ma Z, Tong J, Tang Y, Li S, Qin S, Lou R, Zhao S, Lei X, Shui W Tags: Anal Chim Acta Source Type: research

Fast screening of trace multiresidue pesticides on fruit and vegetable surfaces using ambient ionization tandem mass spectrometry.
Abstract An ambient ionization tandem mass spectrometric approach was developed to rapidly screen multiresidue pesticides on fruits and vegetables without sample preparation and chromatographic separation. The residual pesticides on fruits and vegetables were collected by sweeping a metallic probe across the sample surface for 2 cm. The analytes collected on the probe were desorbed and ionized in a thermal desorption electrospray ionization (TD-ESI) source, after which analyte ions were detected by a triple quadruple mass analyzer (QqQ) operated in multiple reaction monitoring (MRM) mode. With this TD-ESI/MS/...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Cheng SC, Lee RH, Jeng JY, Lee CW, Shiea J Tags: Anal Chim Acta Source Type: research

Rapid, hand-held paper diagnostic for measuring Fibrinogen Concentration in blood.
In this study, we have developed a hand-held paper diagnostic that measures plasma fibrinogen concentrations. The diagnostic has the potential to be used as a point of care device both inside and outside of hospital settings. It can vastly reduce the time to treatment for fibrinogen replacement therapy. The diagnostic is a two-step process. First, thrombin and plasma are added onto horizontially-orientated paper strips where the fibrinogen is converted into fibrin, drastically increasing the plasma's hydrophobicity. Second, an aqueous blue dye is pipetted onto the strips and allowed to wick through the fibrin. The distance...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Bialkower M, McLiesh H, Manderson CA, Tabor RF, Garnier G Tags: Anal Chim Acta Source Type: research

Lighting-up RNA aptamer transcription synchronization amplification for ultrasensitive and label-free imaging of microRNA in single cells.
Abstract Sensitive imaging of intracellular microRNAs (miRNAs) in cells is of great significance in clinical diagnoses and disease treatments, and it remains a major challenge to achieve this goal. Herein, we report a new in situ rolling circle transcription synchronization machinery (RCTsm) of lighting-up RNA aptamer strategy for highly sensitive imaging and selective differentiation of miRNA expression levels in cells. Such a RCTsm approach utilizes a DNA promoter to recycle the target miRNAs to trigger the initiation of multiple RCT process for the yield of many lighting-up RNA aptamers. The malachite green dye...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Li D, Yang F, Yuan R, Xiang Y Tags: Anal Chim Acta Source Type: research

Ratiometric fluorescent sensing system for drug residue analysis: Highly sensitive immunosensor using dual-emission quantum dots hybrid and compact smartphone based-device.
Abstract Immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are utilized extensively for detecting protein biomarkers and small molecules in healthcare, environmental monitoring, and food analysis. Unfortunately, the current strategies for immunoassays often require sophisticated apparatus such as a microplate reader, which might not be available in resource-limited areas. To mitigate this problem, we designed a compact smartphone based-device and a multicolor response immunosensor. First, we designed a compact and cost-effective 3D-printed attachment, where a light-emitting diode was used as a lig...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Yu W, Jiang C, Xie B, Wang S, Yu X, Wen K, Lin J, Wang J, Wang Z, Shen J Tags: Anal Chim Acta Source Type: research

A red-shifted Bioluminescence Resonance Energy Transfer (BRET) biosensing system for rapid measurement of plasmin activity in human plasma.
Abstract Proteases are key signalling molecules for many physiological processes and their dysregulation is implicated in the progression of a range of diseases. Sensitive methods to measure protease activities in complex biological samples are critical for rapid disease diagnoses. The proteolytic activity of plasmin reflects the fibrinolysis state of blood and its deregulation can indicate pathologies such as bleeding events. While Bioluminescence Resonance Energy Transfer (BRET) is a powerful and sensitive method for the detection of protease activity, the commonly applied blue-shifted BRET2 system, consisting o...
Source: Analytica Chimica Acta - February 13, 2020 Category: Chemistry Authors: Weihs F, Peh A, Dacres H Tags: Anal Chim Acta Source Type: research

Chemometric challenges in development of paper-based analytical devices: Optimization and image processing.
Abstract Although microfluidic paper-based analytical devices (μPADs) get a lot of attention in the scientific literature, they rarely reach the level of commercialization. One possible reason for this is a lack of application of machine learning techniques supporting the design, optimization and fabrication of such devices. This work demonstrates the potential of two chemometric techniques including design of experiments (DoE) and digital image processing to support the production of μPADs. On the example of a simple colorimetric assay for isoniazid relying on the protonation equilibrium of methyl orange, t...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Hamedpour V, Oliveri P, Leardi R, Citterio D Tags: Anal Chim Acta Source Type: research

Enzyme induced molecularly imprinted polymer on SERS substrate for ultrasensitive detection of patulin.
Abstract We designed a new type of MIP-SERS substrate for specific and label-free detection of patulin (PAT), by combining molecular imprinting polymer (MIP) selectivity and SERS technology sensitivity. Initially, the solid substrate of PDMS/AAO was prepared using poly dimethylsiloxane (PDMS) concreted anodized aluminum oxide (AAO) template. Then moderate Au was sputtered on the surface of PDMS/AAO to obtain Au/PDMS/AAO SERS substrate. Based on the HRP enzyme initiated in situ polymerization on the Au/PDMS/AAO, the MIP-SERS substrate was successfully synthesized with selective polymer and high tense of SERS "...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Zhu Y, Wu L, Yan H, Lu Z, Yin W, Han H Tags: Anal Chim Acta Source Type: research

A new bivalent fluorescent fusion protein for differential Cu(II) and Zn(II) ion detection in aqueous solution.
Abstract Simple and easy to engineer metal-sensing molecules that are capable of differentiating metal ions and producing metal-specific signals are highly desirable. Metal ions affect the thermal stability of proteins by increasing or decreasing their resistance to unfolding. This work illustrates a new strategy for designing bivalent fluorescent fusion proteins capable of differentiating metal ions in solution through their distinct effects on a protein's thermal stability. A new dual purpose metal sensor was developed consisting of biotin protein ligase (BirA) from B. pseudomallei (Bp) fused to green fluor...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Sorenson AE, Schaeffer PM Tags: Anal Chim Acta Source Type: research

Carbon dots as fluorescent nanoprobe for the determination of N-acetyl- β-d-glucosaminidase activity.
Carbon dots as fluorescent nanoprobe for the determination of N-acetyl-β-d-glucosaminidase activity. Anal Chim Acta. 2020 Mar 08;1101:129-134 Authors: Ma J, Zhang H, Peng F, Yang X, Li ZL, Sun L, Jiang H Abstract Carbon dots (CDs) were synthesized from p-aminophenol and ethylenediamine via one-step under mild condition and used as a sensitive fluorescent nanoprobe for the activity determination of N-acetyl-β-d-glucosaminidase (NAG). In this assay, p-nitrophenol was in situ produced from p-nitrophenyl-β-D-N-acetyl-glucosaminide, which was exclusively hydrolyzed by NAG. The UV absorption ...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Ma J, Zhang H, Peng F, Yang X, Li ZL, Sun L, Jiang H Tags: Anal Chim Acta Source Type: research

Amperometric sensor for nanomolar nitrous oxide analysis.
Abstract Nitrous oxide is an important greenhouse gas and there is a need for sensitive techniques to study its distribution in the environment at concentrations near equilibrium with the atmosphere (9.6 nM in water at 20 °C). Here we present an electrochemical sensor that can quantify N2O in the nanomolar range. The sensor principle relies on a front guard cathode placed in front of the measuring cathode. This cathode is used to periodically block the flux of N2O towards the measuring cathode, thereby creating an amplitude in the signal. This signal amplitude is unaffected by drift in the baseline c...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Damgaard LR, Kelly C, Casciotti K, Ward BB, Revsbech NP Tags: Anal Chim Acta Source Type: research

Self-plasticized, lumogallion-based fluorescent optical sensor for the determination of aluminium (III) with ultra-low detection limits.
Abstract Aluminium-selective ion optical sensor based on covalently attached lumogallion methacrylate was synthesized and investigated in this study. Lumogallion based derivatives were copolymerized with various methacrylate monomers via a simple one step free radical polymerization to produce a "self-plasticized" copolymer. We demonstrate that covalently attached lumogallion moieties provide adequate functionality to the optical film thus achieving a very simple, one component sensing membrane. Fluorescence experiments demonstrated excellent sensitivity towards aluminium (III) ions with the detection li...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Mendecki L, Granados-Focil S, Jendrlin M, Mold M, Radu A Tags: Anal Chim Acta Source Type: research

In  vitro selection of DNA aptamers and their integration in a competitive voltammetric biosensor for azlocillin determination in waste water.
In vitro selection of DNA aptamers and their integration in a competitive voltammetric biosensor for azlocillin determination in waste water. Anal Chim Acta. 2020 Mar 08;1101:149-156 Authors: Chinnappan R, Eissa S, Alotaibi A, Siddiqua A, Alsager OA, Zourob M Abstract The uncontrolled usage of veterinary antibiotics has led to their widespread pollution in waterways and milk products. Potential impact of antibiotic residues on the environment and human health such as increased antibiotic resistance of microorganisms and triggering allergic reactions in humans have been reported. In this work, we ...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Chinnappan R, Eissa S, Alotaibi A, Siddiqua A, Alsager OA, Zourob M Tags: Anal Chim Acta Source Type: research

Instantaneous trace detection of nitro-explosives and mixtures with nanotextured silicon decorated with Ag-Au alloy nanoparticles using the SERS technique.
Abstract The development of recyclable surface enhanced Raman scattering (SERS) based sensors has been in huge demand for trace level explosives detection. A simple, hybrid Silicon (Si) nanotextured target-based SERS platform is fabricated through patterning micro square arrays (MSA) on Si using femtosecond (fs) laser ablation technique at different fluences. Using the hybrid target Si MSA substrate loaded/decorated with Ag-Au alloy NPs (obtained using femtosecond ablation in liquids) we demonstrate the trace level detection of organic nitro-explosives [picric acid (PA), 2,4-dinitrotoluene (DNT), and 1, 3, 5-trini...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Moram SSB, Shaik AK, Byram C, Hamad S, Soma VR Tags: Anal Chim Acta Source Type: research

Direct detection of circRNA in real samples using reverse transcription-rolling circle amplification.
Abstract Circular RNA is a novel class of endogenous non-coding RNA that has a well-conserved sequence. Emerging evidence has shown that circRNA is implicated in various biological processes, therefore, the ability to quantify circRNA in real samples facilitates the elucidation of circRNA related regulatory circuits and its disease associations. Here, a reverse transcription mediated rolling circle amplification process was proposed to achieve selective amplification of the target circRNA. This assay, termed reverse transcription-rolling circle amplification (RT-RCA), can be used to identify circRNA with high sele...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Liu Y, Zhang X, Liu M, Xu F, Zhang Q, Zhang Y, Weng X, Liu S, Du Y, Zhou X Tags: Anal Chim Acta Source Type: research

A multi-parameter in-situ water quality analyzer based on a portable document scanner and 3D printed self-sampling cells.
Abstract This research introduced a new low-cost and multi-parameter analyzer for in-situ measurements of typical nutrients in water bodies. The analyzer consisted of color detection and chromogenic reaction modules. The self-sampling action of the 3D printed sampling/reaction cells was achieved with the cooperative application of rubber bands and dissolvable thread. The target analytes in the collected water sample reacted with the chromogenic reagents that were diffused from the pre-placed glass wool in the cell, producing color compounds. A portable document scanner was employed as a multi-parameter in-situ det...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Lin B, Xu J, Yu C, Chen L, Lu M, Xie X Tags: Anal Chim Acta Source Type: research

An automatic online solid-phase dehydrate extraction-ultra-high performance supercritical fluid chromatography-tandem mass spectrometry system using a dilution strategy for the screening of doping agents in human urine.
Abstract An automatic online solid-phase dehydrate extraction (SPDE)-ultra-high performance supercritical fluid chromatography (UHPSFC)-MS/MS system was developed in this study, in which the automatic SPDE procedure was coupled with UHPSFC to allow UHPSFC to analyze aqueous samples directly. Moreover, a pre-column dilution strategy was employed, which focused the analytes in strong desorption solvent on the column head and helped to obtain narrow and symmetric peaks. The online SPDE-UHPSFC-MS/MS system was firstly applied to the screening of 45 prohibited substances in human urine for doping control, during which ...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Liang Y, Liu J, Zhong Q, Huang T, Zhou T Tags: Anal Chim Acta Source Type: research

05SAR-PAGE: Separation of protein dimerization and modification using a gel with 0.05% sarkosyl.
Abstract A protein gel electrophoresis procedure using 0.05% w/v sarkosyl, is reported. The method called 05SAR-PAGE can be used to identify the native masses, dimeric states and modification states of proteins, and also be suitable for pursuing native electroblotting and immunodetection. It has been demonstrated by NMR spectroscopy that 0.05% w/v SAR is much milder than SDS, so it has subtle effects on the native structure of proteins. Therefore, the non-covalent dimerization of PhoBN and PhoRcp can be identified by 05SAR-PAGE which cannot be observed by SDS-PAGE. It has also been demonstrated that 05SAR-PAGE can...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Huang L, Kou X, Zheng W, Xiao X, Li C, Liu M, Liu Y, Jiang L Tags: Anal Chim Acta Source Type: research

Miniature and fully portable gradient capillary liquid chromatograph.
Abstract A robust, portable and miniature battery powered gradient capillary liquid chromatograph (total weight ∼2.7 kg, without battery ∼2.0 kg), with integrated microfluidic injection, column heating and high sensitivity low-UV absorbance detection is presented. The portable capillary chromatograph, was applied with a packed reversed-phase capillary column (100 mm × 300 μm I.D., 5 μm ODS), housed within an integrated capillary column heater controlled by a proportional-integral-derivative (PID) chip module. The system delivered retention time and peak area r...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Lam SC, Coates LJ, Hemida M, Gupta V, Haddad PR, Macka M, Paull B Tags: Anal Chim Acta Source Type: research

Determination of phototoxic furanocoumarins in natural cosmetics using SPE with LC-MS.
Abstract Furanocoumarins are a class of naturally occurring phototoxic substances widely spread throughout the Umbelliferae and Rutacea families of plants. Plant extract of these families (e.g. citrus extracts) are commonly used as ingredients in fragrances and cosmetic products. Due to their phototoxicity these substances are regulated within the European Union according to the European Regulation (EC) No. 1223/2009 on cosmetic products. The proposed analytical workflow aims to swiftly screen out and determine the amount of phototoxic furanocoumarins in natural cosmetics employing solid-phase extraction (SPE). Co...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Kreidl M, Rainer M, Jakschitz T, Bonn GK Tags: Anal Chim Acta Source Type: research

Fabrication and application of zwitterionic phosphorylcholine functionalized monoliths with different hydrophilic crosslinkers in hydrophilic interaction chromatography.
In this study, a series of zwitterionic phosphorylcholine functionalized monolithic columns were fabricated via the thermally initiated co-polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and different hydrophilic crosslinkers, including 1,4-bis(acryloyl)piperazine (PDA), N,N'-methylenebisacrylamide (MBA) and 2-(methacryloyloxy)ethyl-[N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC). The physicochemical and chromatographic properties of these MPC functionalized monoliths, including column morphology, pore size distribution, permeability, column efficiency, retention mechanism and ζ-potential analysi...
Source: Analytica Chimica Acta - February 9, 2020 Category: Chemistry Authors: Wang Q, Zhang Q, Huang H, Zhao P, Sun L, Peng K, Liu X, Ruan M, Shao H, Crommen J, Yu P, Jiang Z Tags: Anal Chim Acta Source Type: research