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The article focuses on the history, present, and future perspectives of analytical chemistry teaching in China. Topics discussed include the release of the earliest chemistry book titled "Quantitative Chemical Analysis," Yuanyu Cao in 1939, the offering of five chemistry courses including organic, physical, and analytical chemistry, and the consideration of the advanced analytical chemistry as an applied science.

A novel near-infrared (NIR) fluorescent probe based on cyanine dyes was designed and synthesized to detect nitroreductase (NTR) activity. Upon reaction with NTR, the nitro-group of p-nitrobenzyl moiety was reduced to amino-group and therefore renews the π-electron conjugation of the dye, resulting in the intense NIR fluorescent emission (708 nm). This redox-induced NIR-fluorescence probe has been successfully applied to the detection of NTR activity under physiological conditions with high selectivity. [ABSTRACT FROM AUTHOR]

Elements and quantification: A nucleic acid assay has been developed, based on an elemental labeling strategy using magnetic microparticles (MMPs), which provides quantification of multiple DNA targets. Rare‐earth elements, indium, and stable isotopes could be labeled with oligonucleotides serving as DNA probes. Quantitative analysis was then carried out using the designed systems (see picture) and elemental mass spectrometry. [ABSTRACT FROM AUTHOR]

Elemente und Quantifizierung: Ein Nucleinsäure ‐ Assay, der auf einer Elementmarkierungsstrategie mit magnetischen Mikropartikeln (MMPs) beruht, ermöglicht die Quantifizierung mehrfacher DNA ‐ Ziele. Seltenerdelemente, Indium und stabile Isotope konnten mit Oligonucleotiden, die als DNA ‐ Sonden dienen, markiert werden. Die quantitative Analyse wurde dann mit den entworfenen Systemen (siehe Bild) und Massenspektrometrie durchgeführt. [ABSTRACT FROM AUTHOR]

Abstract: The elucidation of reaction mechanisms in inorganic and organic chemistry, and more recently in supramolecular chemistry, has attracted great interest. Better understanding of these mechanisms would enable people to work more wisely and innovatively in designing new reactions and synthesizing novel chemicals and materials. In addition, monitoring both substrates and reaction products during the reaction process aids the study of reaction dynamics, which will be helpful in optimizing reaction conditions. In comparison with other reaction-monitoring techniques [e.g., electron-spin resonance spectroscopy, ultraviolet spectroscopy and chemically-induced dynamic nuclear polarization], mass spectrometry is widely used due to its high sensitivity, specificity and scanning speed. In this review, we focus on ambient ion sources that have undergone rapid development in the past decade and greatly facilitate direct, rapid analysis of samples with little or no sample preparation. These ion sources, including but not limited to desorption electrospray ionization, extractive electrospray ionization, low-temperature plasma probe, electrospray-assisted laser desorption/ionization, and desorption/ionization on porous silicon, offer varied reaction times (several milliseconds to several minutes) and are controlled by corresponding experimental parameters. We discuss examples of different ion sources coupled with MS for reaction monitoring and highlight some of their unique applications in bioorganic and organic chemical reactions. We believe that, with this abundant toolbox of ion sources as sampling methods, we can be more confident in choosing the most effective technique to address problems of interest in reaction monitoring. [Copyright &y& Elsevier]

Here we report a novel aerosol chemiluminescence (CL)-based sensor array containing six kinds of catalytic nanoparticles for the pattern recognition of organic compounds in aqueous solutions, which functions as a mammalian tongue. The catalytic oxidization of sample aerosols produces distinct CL response patterns on the array, which are highly repeatable and can be differentiated by linear discriminant analysis (LDA). Fourteen organic compounds including three saccharides, two organic acids, and nine amino acids, which are common small biomolecules, have been classified successfully by their characteristic patterns. A training matrix (6 nanoparticles × 14 analytes × 5 replicates) has been generated and used to identify 126 unknown solution samples at three different concentrations with an accuracy of 100%. The applicability of this array for real-life samples has been demonstrated by discriminating eight beverages. The stable and reversible response of this array, combined with its simple instrumentation and long lifetime, indicates the promise of this array for real-world application. [ABSTRACT FROM AUTHOR]

Abstract: An optical sensor for ethanol has been proposed by trapping the analytes on sensing nanomaterials at room temperature and detecting them in situ by recording the cataluminescence (CTL) signals with fast elevated temperature. Sensing nanomaterials of ZrO2 were directly deposited on heating filament which enables the temperature programming for trapping and detecting the interested analytes. The miniaturized sensing unit has low incandescent radiation so as to provide the high signal-to-noise ratio. Under the optimized conditions, the linear range for the determination of ethanol vapor is 1.0×10−3 to 1.0mgL−1. A detection limit (S/N=3) is 2.0×10−4 mgL−1 (0.1ppm), which is improved about 3000-fold for ethanol compared with previous CTL sensors. The relative standard deviation (RSD) is 1.2% (n =7) for ethanol samples at a concentration of 0.08mgL−1. The stability was demonstrated by continuous reaction with ethanol for 120h. This sensor has been applied to monitor the ethanol concentration in human expired gas after drinking, and the results agreed well with the reference values. This miniature ethanol sensor offers higher sensitivity, faster response and lower power consumption, which make it very promising in developing hand-hold sensing device for field detection. [Copyright &y& Elsevier]

Abstract: The near-stoichiometric LiNbO3 (SLN) single crystals doped Mn2+, Co2+ and Ni2+ in 0.5mol% concentration in the raw compositions were grown by the Bridgman method under the conditions of taking K2O as flux, a high temperature gradient (90–100°C/cm) for solid–liquid interface. The XRD, absorption spectra, excitation spectra and emission spectra have been carried out. From the absorption edges of Mn2+, Co2+ and Ni2+-doped SLN crystals, the molar ratio of [Li+]/[Nb5+] are estimated to be about 0.977. The absorption spectra of Mn2+:SLN have shown a broad absorption band centered at ∼571nm (6A1g(6S)→ 4T1g(4G)), three absorption peaks at 520, 549 and 612nm (overlapping of the 4T1(F)–4A2(F), 4T1(F)–4T1(P)), and a wide absorption band at 1400nm (4T1(F)→ 4T2(F)) of Co2+:SLN, Ni2+:SLN, and five absorption peaks at 381nm (3A2g(F)→ 3T1g(P)), 733nm (3A2g(F)→ 3T1g(F)), 1280nm (3A2g(F)→ 3T2g(F)), 430nm (3A2g(F)→ 1T2g(D)), and 840nm (3A2g(F)→ 1E(D)) of Ni2+:SLN were observed. A red emission at 612nm (4T1g(4G)→ 6A1g(6S)) for Mn2+:SLN, a red emission at 775nm (4T1(P)→ 4T1(F)) for Co2+:SLN, and a green emission at 577nm (1T2g(D)→ 3A2g(F)) and a red emission at 820nm (1T2g(D)→ 3T2g(F)) for Ni2+:SLN were observed under excited by 416, 520 and 550nm lights, respectively. The concentration distribution of Mn2+, Co2+and Ni2+ ion in SLN crystals was investigated primarily from the absorption and emission spectra for various parts. The effective distribution coefficient for Mn2+ was less than 1. While, for Co2+ and Ni2+ were more than 1. [Copyright &y& Elsevier]

A direct and sensitive method for the detection of methyl centralite (MC) and ethyl centralite (EC) as gunshot residues (GSRs) has been developed. This method uses desorption electrospray ionization (DESI)-tandem mass spectrometry and directly desorbs and detects analytes from surfaces without any sampling process. Typical transitions for MC and EC, m/z 241 to m/z 134 and m/z 269 to m/z 148, respectively, were used to improve the assay sensitivity. It has been shown that MC and EC can be detected on various surfaces, with detection limits of 5–70 pg/cm2. Interferences, detection time after shooting and the number of times hands were washed after shooting were also evaluated. None of the materials interfered with the results and the detection window for organic GSRs was up to 12 h and hands could be washed at least six times. Further samples were analyzed to confirm the reliability of this method, and showed that it could discriminate shooters from nonshooters. This method should be of significance in forensic science, especially in analyzing GSRs, because of its simplicity, high throughput, and the direct detection of MC and EC on suspects’ hands, clothes, and hair. [ABSTRACT FROM AUTHOR]

Abstract: A gaseous sensor for ester vapors has been developed based on their chemiluminescence (CL) on the surface of nano-sized SiO2 in an airflow. The luminescence characteristics and the optimal conditions for the determination of ethyl acetate by the sensor are investigated. Under the optimized conditions, the linear range of the CL intensity versus the concentration of ethyl acetate vapor is 20–300ppm with a limit of detection of 3.0ppm (3σ) and a relative standard deviation (R.S.D.) of 1.80% for eight times determination of 300ppm ethyl acetate. There is no response or weak response when foreign substances including ethanol, methanol, hexane, cyclohexane, benzene and toluene pass through the sensor. However, acetone shows a little response which interferes slightly in the measurement of ethyl acetate. The sensor exhibits good stability and durability after 100h reaction with 300ppm ethyl acetate. The possible mechanism of CL from the oxidation of ethyl acetate on SiO2 is discussed based on the CL spectra and the GC–MS chromatogram of reaction products. [Copyright &y& Elsevier]

Abstract: The atomization of hydride-forming elements, Se, Sb and Sn, has been studied with an atmospheric pressure dielectric barrier discharge atomizer. The elements were first converted to hydride through the reaction with NaBH4. Then the hydride were atomized in the atomizer and detected by atomic absorption spectrometry. The effects of operational parameters such as power, gas flow rate and concentrations of HCl and NaBH4 were investigated. Compared with other hydride atomization methods, the proposed atomizer shows the following features: (1) small size, which is preferable for the miniaturization of the total analytical system; (2) low temperature, which would be helpful for further improvement in the compactness of the total analytical system; (3) low power consumption, which is also necessary for the development of analytical instrumentation for in situ detection of environmentally important elements. The analytical performance of the atomizer has also been investigated. The detection limits of Sb, Se and Sn obtained with the present method were 13.0, 0.6 and 10.6 μg l−1. This detector is a very promising technique for hydride detection. [Copyright &y& Elsevier]

Abstract: This is a brief review on the developments and applications of chemiluminescence (CL) sensors dated from 1999 to present. Methods and materials for immobilization of CL reagents are introduced. The CL-based sensors, including the sensors for the detection of inorganic species, organic species and biological macromolecules are summarized. The advantages and limitations of CL sensors are discussed. [Copyright &y& Elsevier]

This paper describes a novel aerosol chemiluminescence- based detector, which can be coupled to liquid chromatography for the determination of the chemicals with weak optical absorbance in the UV-visible region. This aerosol chemiluminescence (CL)-based detector, in which HPLC effluent is converted to aerosol and then generated CL emission on the surface of porous alumina, is composed of three main processes: nebuliztion of HPLC effluent, CL emission on surface of porous alumina material, and optical detection. To demonstrate the utility of the aerosol chemiluminescence detector, some compounds such saccharides, poly(ethylene glycol)s, amino acids, and steroid pharmaceuticals are determined by the present aerosol chemiluminescence detection method. Compared with an evaporative light scattering detector, the proposed detector shows the following features: (a) extensive CL emissions on porous alumina by many compounds tested, which leads to the potential application for the determination of volatile and nonvolatile chemicals with or without UV-visible absorbance; (b) a CL mechanism based on the catalytic oxidation of analytes, not on the light scattering, which suggests the present detector be free from the interference of the inorganic and nonvolatile mobile-phase modifiers. The CL characteristics and effect of different parameters, such as temperature and nebulizer gas flow rate, were also discussed in this paper. Furthermore, this aerosol chemiluminescence-based detector was success- fully applied to the determination of raffinose, glucose, sucrose, maltose, and α-lactose. [ABSTRACT FROM AUTHOR]

A sensitizing effect of papaverine on the weak chemiluminescence (CL) reaction of sulfite with acidic cerium(IV) is studied. In papaverine and cerium(IV) solution, the increase in the fluorescent intensity of cerium(III) at 360 nm with an increasing time indicates a slow oxidation of papaverine by acidic cerium(IV). This reaction results in the formation of intermediate radical of papaverine, which enhanced the CL emission of sulfite–cerium(IV) system. Based on this finding, a flow injection (CL) method is proposed for the determination of papaverine. The CL intensity is proportional to the concentration of papaverine from 1.0 × 10−7 to 1.0 × 10−5 M with a correlation coefficient of 0.9991. The detection limit is 8.7 × 10−8 M (3σ). The relative standard deviation for seven independent determinations of 1.0 × 10−6 M papaverine is 2.0%. The proposed method has been satisfactorily used for the determination of papaverine in pharmaceutical preparations and biological fluids. [ABSTRACT FROM AUTHOR]

The weak chemiluminescence (CL) from the reaction of hemoglobin (Hb) with hydrogen peroxide in an aqueous carbonate solution was significantly enhanced in the presence of β-cyclodextrin (β-CD). The mechanism was discussed by examining CL emission spectrum and the effect of various free radical scavengers on CL emission intensity. The β-CD could form encapsulation complex with heme, which was dissociated from Hb in alkaline medium. The formed complex showed better catalytic activity than free heme thus resulting in an enhanced CL emission intensity. A flow injection CL method for the determination of Hb ranging from 2.0×10−9 to 1.0×10−5 g ml−1 was developed with β-CD as a sensitizer. The detection limit (3σ) for Hb was 1.2×10−9 g ml−1 (1.9×10−11 mol l−1) and the relative standard deviation (R.S.D.) for seven independent detections of 1.0×10−7 g ml−1 Hb was 2.4%. Since metal ions could not form complex with β-CD, this method showed a good selectivity. The proposed method was used for the determination of Hb in human blood and serum. [Copyright &y& Elsevier]

Lymphocytes play crucial roles in the human immune system; however, detailed metabolite characteristics need to be further investigated. Herein, we propose a lymphocyte classification method based on metabolite profiling at the single-cell level. The percentages of different lymphocyte types were calculated with a low margin of error, confirming that the metabolites could serve as a basis for lymphocyte classification. Furthermore, we analyzed the CD4/CD8 ratio in human peripheral blood to verify the feasibility of this method for the classification of lymphocyte subtypes. The proposed method is expected to be a potential tool for the clinical diagnosis of lymphocyte-related diseases. [ABSTRACT FROM AUTHOR]

The selective measurement of cellular pH at specific regions is significant for the in-depth study of cell functions and pathological processes. Herein, we combined our previously developed rhodamine B-labeled cell-penetrating peptide spirolactam derivative with quantum dots to create a ratiometric nanobiosensor for the simultaneous sensing and imaging of lysosomes and extracellular pH. [ABSTRACT FROM AUTHOR]

A novel platform for rapid screening of gaseous catalysts in methane activation using ICP-QQQ-MS was developed. The gaseous ion catalysts could be produced in an ICP torch from the bulk solution. The dynamic reaction cell in the ICP-QQQ-MS could be used as the reactor to mix methane with the gaseous ion catalyst to examine the important parts of the catalytic reaction. In this work, 37 kinds of gaseous catalysts were rapidly screened and the results obtained by using the ICP-QQQ-MS were also validated by using another dielectric barrier discharge reactor. The ICP-QQQ-MS platform was not only suitable for catalyst screening in methane activation, but also suitable for other full reactions. [ABSTRACT FROM AUTHOR]

A new ratiometric fluorescent probe based on cell-penetrating peptides (CPPs) was constructed for whole-cell pH mapping and simultaneous measurement of pH changes in the cytoplasm and lysosomes. The arginine-rich CPP, R 12 K worked as linker, carrier and part of the fluorophore. Benefiting from R 12 K, the fluorescent probe is completely water soluble, membrane permeable and well biocompatible. It shows high selectivity, sensitivity and reversibility to pH fluctuations. The ratio of fluorescence intensities F 519 /F 582 increased from 0.2 to 9.2 over the pH range from 3.3 to 8.1. Intracellular pH mapping was successfully realized owing to the wide distribution of the probe in live cells (even in nucleus). Moreover, cytosolic and lysosomal pH change caused by the stimuli can be simultaneously detected. Compared to other ratiometric pH probes, RhB-R 12 K-FITC can provide more precise information about H + redistribution between different cellular compartments. [ABSTRACT FROM AUTHOR]

A colorless and nonfluorescent spirolactam derivative, RhB-R12K, was synthesized by amide condensation between the carboxyl group of rhodamine B (RhB) and the amino group of cell-penetrating peptide (CPP). The fluorescence intensity of RhB-R12K sharply increased as the pH value decreased from 8.0 to 4.9, demonstrating sensitive and reversible response to intracellular pH distribution. This CPP probe was completely water soluble, had low cytotoxicity, was membrane permeable, and was suitable for pH measurement in various organelles by choosing organelle-specific CPP sequences. Interestingly, CPPs acted not only as carriers but also as indispensable parts of fluorophores here. The presence of active groups on the peptides potentially allows for modification with additional dyes to construct multifunctional and ratiometric probes for cell imaging. [ABSTRACT FROM AUTHOR]

A multiplex ICP-MS-based miRNA assay with duplex-specific nuclease amplification using bifunctional oligonucleotide probes was proposed. A multiplex assay of miR-141, let-7d, and miR-21 could be achieved simultaneously. [ABSTRACT FROM AUTHOR]

Metabolites are the end products of cellular vital activities and can reflect the state of cellular to a certain extent. Rapid change of metabolites and the low abundance of signature metabolites cause difficulties in single-cell detection, which is a great challenge in single-cell metabolomics analysis. Mass spectrometry (MS) is a powerful tool that uniquely suited to detect intracellular small-molecule metabolites and has shown good application in single-cell metabolite analysis. In this mini-review, we describe three types of emerging technologies for MS-based single-cell metabolic analysis in recent years, including nano-ESI-MS based single-cell metabolomics analysis, high-throughput analysis via flow cytometry, and cellular metabolic imaging analysis. These techniques provide a large amount of single-cell metabolic data, allowing the potential of MS in single-cell metabolic analysis is gradually being explored and is of great importance in disease and life science research. [ABSTRACT FROM AUTHOR]

NK cell-mediated immunotherapy has received increasing attention in the past decade due to its efficacy and bio-safety. The composition and content of lipids in individual cells are closely related to NK cell-mediated cytotoxicity, especially polyunsaturated fatty acids (PUFA) which are oxidized during NK cell-mediated apoptosis. Here we investigated the changes of lipids in single HepG2 cells by label-free mass cytometry and obtained information on 53 lipids and 13 oxidized lipids after the interaction with NK92 MI cells. We found that the contents of lipids and oxidized lipids of HepG2 cells changed obviously during the NK cell-mediated apoptosis. The HepG2 cells could be classified into two phenotypes after co-culturing with NK92 MI cells based on the ratio of PC(38:6-2OH)/PC(38:6) in individual cells, which may serve as a feature to evaluate NK cell-mediated cytotoxicity. The present work used the lipids and oxidized lipids of individual cells to reveal the heterogeneity in NK cell-mediated apoptosis which would be a powerful method for evaluating the cytotoxicity of NK cells at the single-cell level. [ABSTRACT FROM AUTHOR]

Methylmercury (CH3Hg) is one of the most widespread toxic contaminants. Although the formation of CH3Hg in aqueous environments has been widely investigated, little information is available on direct anthropogenic or natural emissions of CH3Hg to the atmosphere. In this work, ICP-MS/MS was chosen as a tool to study abiotic methylation of inorganic mercury reacting with VOCs in a gas environment for the first time. We found that the gaseous Hg+ ions were transformed to the more toxic CH3Hg+ ions instantaneously when colliding with some VOCs. Several VOCs, e.g., methyl iodide (CH3I), methylbenzene, acetic acid and ethyl acetate, exhibited good methylation of Hg+ ions with productivities of 1.77%, 1.28%, 1.35% and 1.18%, respectively. Four isotope peaks of CH3199Hg (M = 214), CH3200Hg (M = 215), CH3201Hg (M = 216) and CH3202Hg (M = 217) were identified when Hg+ ions collided with CH3I, and the methyl group in CH3Hg+ was validated by the source of CD3I, indicating that CH3Hg+ ions were formed. This study reveals that the abiotic methylation of Hg+ ions could occur when in contact with the VOCs in the atmosphere, leading to secondary environmental pollution. [ABSTRACT FROM AUTHOR]

Steroid hormones play important roles in metabolism and metabolic diseases. Currently, various detection methods are employed in clinical labs, mainly immunoassays and LC-MS/MS, but these methods suffer from antibody cross-reactivity or the need for complex LC processes, respectively. Here, we utilized single antibody to capture and separate multiple hormones from samples to avoid LC procedures and used MS/MS to analyze multiple molecules in a single run. In our strategy, testosterone (T), androstenedione (4-AD), and androsterone (ADT) were affinity-captured simultaneously using only T antibody. The qualitative and quantitative analysis of three androgens was realized through MS/MS spectra using testosterone-D3 (T-D3) as an internal standard. Standard curves for standard solution or spiked serum samples were realized in the range of 0.01–2 μg L−1. The LODs for the three androgens were 2.3 × 10−3 μg L−1 for testosterone, 4.6 × 10−3 μg L−1 for androstenedione, and 2.8 × 10−3 μg L−1 for androsterone. The recovery results verified the reliability and stability of our method. This strategy has widespread potential for advancing the combination of immunoassay and MS methods in the analysis of small molecules, with high through-put and low cost. [ABSTRACT FROM AUTHOR]

α‐Synuclein is a central player in Parkinson's disease (PD) pathology. Various point mutations in α‐synuclein have been identified to alter the protein‐phospholipid binding behavior and cause PD. Therefore, exploration of α‐synuclein‐phospholipid interaction is important for understanding the PD pathogenesis and helping the early diagnosis of PD. Herein, a phospholipid‐decorated liquid crystal (LC)‐aqueous interface is constructed to investigate the binding between α‐synucleins (wild‐type and six familial mutant A30P, E46K, H50Q, G51D, A53E and A53T) and phospholipid. The application of deep learning analyzes and reveals distinct LC signatures generated by the binding of α‐synuclein and phospholipid. This system allows for the identification of single point mutant α‐synucleins with an average accuracy of 98.3±1.3% in a fast and efficient manner. We propose that this analytical methodology provides a new platform to understand α‐synuclein‐lipid interactions, and can be potentially developed for easy identification of α‐synuclein mutations in common clinic. [ABSTRACT FROM AUTHOR]

Abstract: An atmospheric pressure dielectric barrier discharge (DBD) atomizer was investigated for bismuth (Bi) determination with hydride generation (HG) atomic fluorescence spectrometry (AFS). The characteristics of the atomizer and the effects of experimental parameters, including observation height, discharge power, flow rate of discharge gas and AFS carrier gas were optimized. The linear range of present method for Bi determination is 0.5–300.0μgL−1 with a detection limit of 0.07μgL−1 (3σ). The method was validated by the analysis of reference materials (GBW08517 and GSB-14) and the results agreed well with the reference values. The established method was applied to the determination of Bi in ore, soil and ash samples. [Copyright &y& Elsevier]

A highly sensitive immunoassay is proposed based on time-resolved inductively coupled plasma mass spectrometry with nanoparticles as tags to antibody. Instead of using traditional integral mode detection, the transient signals induced by the flash of ions in the plasma torch from the ionization of nanoparticles tagged on antibody were recorded in a time-resolved mode. Since, under certain conditions, the frequency of transient signals is directly correlated to the concentration of nanoparticle tags, the concentration of nanoparticle-tagged antibodies can be quantified by the frequency of transient signals. With the present instrument setup, gold nanoparticle (Au-NP) tags, as small as about 15 nm in diameter, can be detected. This protocol is evaluated for a competitive immunoassay and the linear range for α-fetoprotein is 0.016–6.8 μg/L (between 20 and 80% inhibition). The limit of quantification is 0.016 μg/L (20% inhibition, IC20) with a relative standard deviation of 4.2% (20% inhibition, 4 replicates) for α-fetoprotein. The present strategy provides a sensitive readout method for nanoparticle tags, which is quite promising for numerous applications in immunoassay, DNA hybridization, and other biological analyses. [Copyright &y& Elsevier]

Abstract: At least 25 selenoproteins in humans and 24 homologues in rodents have been identified. They play important roles in antioxidation, redox regulation and detoxification. The modulation of the expression of selenoproteins by inorganic arsenic (iAs) exposure may highlight the molecular mechanism for the arsenic toxicity. To investigate the effects of iAs exposure on the expression of selenoproteins, we determined how addition of iAs to culture medium affected all known selenoproteins in the mouse embryonic stem (ES) cells. Separated groups of ES cells were treated with arsenite (iAsIII) (0.25–0.5μM), arsenate (iAsV) (1.0–2.0μM) and co-treatment with sodium selenite (SeIV) (0.5μM). The mRNA levels of all selenoproteins were detected by real time quantitative PCR. The up-regulated selenoproteins were confirmed by immunoblotting analysis and enzymatic activity detection. Results showed that CGR8 cells treated with iAsIII (0.25–0.5μM) and iAsV (2.0μM) displayed significant increases of cellular reactive oxygen species (ROS) generation and nuclear accumulation of the transcription factor NF-E2-related factor 2 (Nrf2). Treatments of iAsIII (0.5μM) or iAsV (2.0μM) for 24h caused significant increases in the expression of the antioxidant selenoproteins (Gpx1, Gpx4, and Tr1), whereas led to significant decreases in the mRNA levels of selenoprotein H and some endoplasmic reticulum (ER) located selenoproteins (15-Sep, SelK, SelM, and SelS). Additionally, supplement of SeIV (0.5μM) could restore most of the down-regulated selenoproteins. These results suggested that iAs exposure modulated not only the antioxidant selenoproteins but also the ER stress associated selenoproteins. Further studies are required to clarify whether these modulated selenoproteins genes are targets for selenium supplement in the defense against the toxicity of iAs. [Copyright &y& Elsevier]

Abstract: A flameless atomizer for atomic fluorescence spectrometry (AFS), based on an atmospheric pressure dielectric barrier discharge, has been developed for the atomization of hydride-forming elements, such as Se, Sb and Pb. The atomizer (8 mm o.d, 35 mm length) was operated at a power less than 50 W. The discharge was sustained with argon at the flow rate of 0.85 L min−1 after optimization. The characteristics of the atomizer and the effects of different parameters (power, gas flow rate, and KBH4 concentration) are investigated. The most attractive feature of this atomizer is its low operation temperature (~52 °C, detected at the outlet of the atomizer by a thermocouple), allowing both the radiation source and the detector to be placed in close proximity with the atomizer. The analytical performance of the atomizer has been evaluated, and detection limits for Se, Sb and Pb obtained with the present technique were 0.08, 0.11 and 0.27 μg L−1, respectively. The accuracy of the system was verified by the determination of Se, Sb and Pb in reference material of spinage GBW 10015. The concentrations of Se, Sb, and Pb determined by the present technique agreed well with the reference values (Se: 92±24 mg kg−1, Sb: 43±14 mg kg−1, Pb: 11.1±0.9 mg kg−1). This detector is very promising for field elements detection with portable AFS. [Copyright &y& Elsevier]

Abstract: A new atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma was specially designed for atomic fluorescence spectrometry (AFS) in order to be applied to the measurement of arsenic. The characteristics of the DBD atomizer and the effects of different parameters (power, discharge gas, gas flow rate, and KBH4 concentration) were discussed in the paper. The DBD atomizer shows the following features: (1) low operation temperature (between 44 and 70°C, depending on the operation conditions); (2) low power consumption; (3) operation at atmospheric pressure. The detection limit of As(III) using hydride generation (HG) with the proposed DBD-AFS was 0.04μgL−1. The analytical results obtained by the present method for total arsenic in reference materials, orchard leaves (SRM 1571) and water samples GBW(E) 080390, agree well with the certified values. The present HG-DBD-AFS is more sensitive and reliable for the determination of arsenic. It is a very promising technique allowing for field arsenic analysis based on atomic spectrometry. [Copyright &y& Elsevier]

A new ion source based on dielectric barrier discharge was developed as an alternative ionization source for ambient mass spectrometry. The dielectric barrier discharge ionization source, termed as DBDI herein, was composed of a copper sheet electrode, a discharge electrode, and a piece of glass slide in between as dielectric barrier as well as sample plate. Stable low-temperature plasma was formed between the tip of the discharge electrode and the surface of glass slide when an alternating voltage was applied between the electrodes. Analytes deposited on the surface of the glass slide were desorbed and ionized by the plasma and the ions were introduced to the mass spectrometer for mass analysis. The capability of this new ambient ion source was demonstrated with the analysis of 20 amino acids, which were deposited on the glass slide separately. Protonated molecular ions of [M + H]+ were observed for all the amino acids except for L-arginine. This ion source was also used for a rapid discrimination of L-valine, L-proline, L-serine and L-alanine from their mixture. The limit of detection was 3.5 pmol for L-alanine using single-ion-monitoring (SIM). Relative standard deviation (RSD) was 5.78% for 17.5 nmol of L-alanine (n = 5). With the advantages of small size, simple configuration and ease operation at ambient conditions, the dielectric barrier discharge ion source would potentially be coupled to portable mass spectrometers. [Copyright &y& Elsevier]

A lysosome-targeting ratiometric fluorescent nanoprobe based on cell-penetrating peptides (CPPs) and quantum dots (QDs) has been developed for monitoring pH fluctuation in living cells. The as-prepared nanoprobe is constructed by Rhodamine B labeled R 9 RGD CPPs as H+ response unit and the red fluorescent QDs as reference unit to achieve ratiometric pH measurement. With the help of RhB-R 9 RGD CPPs, the nanoprobe efficiently stains lysosomes and enables discernment of lysosomal pH fluctuation in cells treated with different pH buffers and drug stimulation. The method of using dye labeled CPPs to realize functionalization of nanoparticle in one-step reported herein is expected to obtain wider applications in the detection of subcellular active substances by combining different small molecular probes and functional peptides. [Display omitted] • A fluorescent pH nanoprobe was developed through the dual functional modification of QDs with CPPs in one-step. • The nanoprobe displays the ability of sensitive, selective and ratiometric detection of protons. • The nanoprobe efficiently stains lysosomes with the help of CPPs. • The nanoprobe enables discernment of lysosomal pH fluctuation in cells treated with different pH buffer and drug stimulation. [ABSTRACT FROM AUTHOR]

A multiplex bacterial assay method that combines S1 nuclease pretreatment and ICP-MS-based elemental labels is presented in this work. Six intestinal related bacteria were identified at the species level and quantified simultaneously without isolation culturing. This method could be extended to assay a mixed bacterial community for point-of-care diagnosis. [ABSTRACT FROM AUTHOR]

Skeletal muscle tissue is composed of various muscle cell types which differ in physiological functions. Changes in cell type composition of skeletal muscle are associated with the development of metabolic diseases. Skeletal muscle cell types are currently distinguished by immunofluorescence (IF) staining based on myosin heavy chain (MHC) isoform difference. However, it remains a challenge to provide metabolic fingerprints of different muscle cell types by IF staining. Therefore, in this study, we proposed a method to examine metabolite distribution within different cell types by time-of-flight secondary ion mass spectrometry (TOF-SIMS) with high spatial resolution. Skeletal muscle samples from C57/BL6 mice were obtained by slicing. Cell types in TOF-SIMS images were labelled corresponding to IF images from the same region of serially cut sections. Mass spectra corresponding to individual muscle cells were extracted to compare metabolic fingerprints among cell types. Skeletal muscle cells were classified into two clusters based on the mass spectra of individual cells. Unsaturated diacylglycerol (DG) and fatty acid (FA) species were found to be distributed in a cell-type dependent manner. Moreover, relative quantification showed that the content of unsaturated DGs, oleic acid and linoleic acid was higher in type I and type IIA cells than in type IIB cells. TOF-SIMS in combination with IF enables us to directly visualize metabolite distribution in different cell types, to find potential biomarkers for cell type classification. TOF-SIMS imaging coupled with IF staining has been proved to be a promising tool for metabolic fingerprinting of different skeletal muscle cell types. [ABSTRACT FROM AUTHOR]

Litharge, in two dimensional (2D) nanostructure form, has recently ignited considerable theoretical interest due to its excellent photoelectric and magnetic properties. However, the lack of an efficient synthesis method hinders its development. Here, we provide an interfacial solvothermal strategy for controllably synthesizing ultrathin hexagonal polycrystalline α-PbO nanosheets in micrometer scale. This strategy can also be utilized for the synthesis of other 2D materials. Experimental atomic force microscope nanoindentation measurements reveal the relationship between the thickness of polycrystalline α-PbO nanosheets and the corresponding Young's modulus, expressed as E = E0 + K t −1. First-principles calculation supports the result and ascribes the cause to interlayer sliding from particular weak interlayer interactions. Additionally, the enhanced mechanical strength of the polycrystalline structure compared to its single-crystal counterpart is attributed to the alternate arrangement of grain-boundaries effects. The summative formula may be extended to other 2D materials with weak interlayer interactions, which has the potential to provide guidance for constructing flexible devices. [ABSTRACT FROM AUTHOR]

Introduction: Element-tagged immunoassay coupled with inductively coupled plasma-mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis in clinical detection; however, a systematic evaluation with the standard guidelines of the assay is needed to ensure its performance meets the requirements of the clinical laboratory. Methods: Carcinoembryonic antigen (CEA) was chosen for analysis using the proposed method. A systematic evaluation of the proposed assay was carried out according to the Clinical and Laboratory Standards Institute (CLSI). The 469 clinical samples were analyzed using the new method and compared with the electrochemiluminescent immunoassay (ECLIA) method. Results: The measurement range of the assay was 1–900 ng/mL, with a detection limit of 0.83 ng/mL. The inter-assay and intra-assay imprecision were 4.67% and 5.38% with high concentration samples, and 9.27% and 17.64% with low concentration samples, respectively. The cross-reactivity (%) for different antigens was less than 0.05%, and the recovery was between 94% and 108%. Percentage deviation of all the dilutions was less than 12.5% during linearity estimation. The interference bias caused by different substances was less than 10%. The reference interval of the assay was 0–4.442 ng/mL. Comparison with the commercial ECLIA method for clinical sample detection, the proposed method showed a correlation of 0.9878 and no significant differences between the methods were observed (p = 0.6666). Conclusions: The ICP-MS based immunoassay was successfully developed, and the analytical performance of the assay met the requirements of the CLSI, which fully proved the clinical transferability and application of the new method. [ABSTRACT FROM AUTHOR]

A simple multiplexed digital microRNA detection strategy with fluorescence flow cytometry was proposed. By isothermal ligation-rolling circle amplification, multiplexed microRNAs could be simultaneously converted to a series of nanoflower balls (NFBs) and counted by flow cytometry directly. [ABSTRACT FROM AUTHOR]

The metal ion-catalyzed (Ru+, Ir+) reactions of ethanol converting to butanol have been studied via ICP-MS/MS. The detection of organic small molecule intermediates (acetaldehyde and butyraldehyde) was achieved in both Ru+/C2H5OH and Ir+/C2H5OH systems. Several metal-adduct intermediates were observed in these reactions, improving the understanding of the reaction mechanism of ethanol transformation. The possible formation pathways of intermediates have been discussed. [ABSTRACT FROM AUTHOR]

Summary: Multicolour structured illumination microscopy (SIM) is a powerful tool used for the investigation of the dynamic interaction between subcellular structures. Nevertheless, most of the multicolour SIM schemes are currently limited by conventional fluorescent dyes and wavelength‐dependent optical systems, and can only sequentially record images of different colour channels instead of obtaining multicolour datasets simultaneously. To address these issues, we present a novel multicolour SIM scheme referred to as quantum dot structured illumination microscopy (QD‐SIM). QD‐SIM enables simultaneously excitation and collection of multicolour fluorescent signals. We also propose a theoretical analysis of the image formation in two‐dimensional multicolour SIM to help combine the optically sectioned and super‐resolution attributes of SIM. Based on this theory, QD‐SIM enables optically sectioned, super‐resolution, multicolour simultaneous imaging at a single plane. [ABSTRACT FROM AUTHOR]

Lipids exert substantial influences on vertebrate embryogenesis, but their metabolic dynamics at detailed structural levels remains elusive, primarily owing to the lack of a tool capable of resolving their huge structural diversity. Herein, we present the first large-scale and spatiotemporal monitoring of unsaturated lipids with C=C specificity in single developing zebrafish embryos enabled by photochemical derivatization and tandem mass spectrometry (MS). The lipid isomer composition was found extremely stable in yolk throughout embryogenesis, while notable differences in ratios of C=C location (e.g., PC 16:0_16:1 (7) vs. 16:0_16:1 (9)) and fatty acyl composition isomers (e.g., PC 16:1_18:1 vs. 16:0_18:2) were unveiled between blastomeres and yolk from zygote to 4 h post fertilization (hpf). From 24 hpf onwards, lipid isomer compositions in embryo head and tail evolved distinctively with development, suggesting a meticulously regulated lipid remodeling essential for cell division and differentiation. This work has laid the foundation for functional studies of structurally defined lipids in vertebrate embryology. [ABSTRACT FROM AUTHOR]

Urban planning requires more public involvement and larger group participation to achieve scientific and democratic decision making. Crowdsourcing is a novel approach to gathering information, encouraging innovation and facilitating group decision-making. Unfortunately, although previous research has explored the utility of crowdsourcing applied to urban planning theoretically, there are still rare real practices or empirical studies using practical data. This study aims to identify the prospects for implementing crowdsourcing in urban planning through a bibliometric analysis on current research. First, database and keyword lists based on peer-reviewed journal articles were developed. Second, semantic analysis is applied to quantify co-occurrence frequencies of various terms in the articles based on the keyword lists, and in turn a semantic network is built. Then, cluster analysis was conducted to identify major and correlated research topics, and bursting key terms were analyzed and explained chronologically. Lastly, future research and practical trends were discussed. The major contribution of this study is identifying crowdsourcing as a novel urban planning method, which can strengthen government capacities by involving public participation, i.e., turning governments into task givers. Regarding future patterns, the application of crowdsourcing in urban planning is expected to expand to transportation, public health and environmental issues. It is also indicated that the use of crowdsourcing requires governments to adjust urban planning mechanisms. • Bibliometric analysis is used to overview current research status of crowdsourcing techniques applied in urban planning. • Being able to collect data efficiently makes crowdsourcing as a promising method to satisfy urban planning needs. • With smart mobile phones, crowdsourcing can be applied extensively, enhancing public participation in urban planning. • Governments should make adjustments in urban planning mechanism to meet the requirements of crowdsourcing. • Public health is identified as a major potential area in which crowdsourcing could be utilized. [ABSTRACT FROM AUTHOR]

Abstract Gold nanoparticles (AuNPs)-embedded paper was coupled with ion-transmission mass spectrometry (MS) to enable the highly sensitive detection of chemical warfare agent (CWA) simulants in solutions. With the assistance of a low-temperature plasma (LTP) probe, we found that AuNPs were capable to enhance the ionization efficiencies of target analytes, with MS signal intensities surprisingly undergone an 800-fold increase under optimized conditions. The interaction between AuNPs and the radiofrequency electromagnetic field was believed to promote the desorption/ionization process, resulting in the unusual signal enhancement phenomenon. Based on this finding, we established a method for the rapid analysis of two simulants of nerve agents, dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP), with a dynamic range from 0.5 ng/mL to 100 ng/mL and detection limits of 0.1 ng/mL and 0.3 ng/mL, respectively. As sample pretreatments have been eliminated, the developed strategy is particularly promising for the on-site detection of CWAs considering its simple and rapid analytical workflow. Graphical abstract fx1 Highlights • AuNPs coupled with a low-temperature plasma could greatly enhance the MS responses of chemical warfare agent simulants. • Activated AuNPs promoted analyte desorption and ionization. • A fast and robust method for quantitation of DMMP and DIMP was developed, with detection limits as low as 0.1 ng/mL obtained. [ABSTRACT FROM AUTHOR]

Ratiometric quantification for competitive immunoassay based on internal standard element detection utilizing inductively coupled plasma mass spectrometry (ICP-MS) as multiplex readout has been demonstrated. The Beta-2-microglobulin (β2-MG) associated with clinical diseases was detected by Y-labeled capture antibody used as internal standard probes and Sm-labeled antigen used as report probes via antigen-antibody reaction. The ratiometric quantification was achieved by taking the signal ratio of Sm/Y. The ratiometric method could compensate for the particle loss and suppress the signal fluctuation, which improved the precision of the quantitative result. Under the optimized conditions, the calibration curves for β2-MG antigen was linear in the range of 0.25–8.0 μg/mL with a detection limit of 0.17 μg/mL (3σ, n = 11). The recoveries of 96.5%–132% were obtained for serum samples spiked with different concentration standards, and the relative standard deviation (RSD) was less than 10%. The β2-MG results in serum samples obtained by the proposed method correlated well with those obtained by time-resolved fluorescence immunoassay (r = 0.947). This proposed method provides a simpler labeling strategy for ratiometric quantification of immunoassay. [ABSTRACT FROM AUTHOR]

A new instrument based on VUV laser desorption/ionization (VUVDI) method was used to measure the mass spectrum of the cholesterol standard and the mass spectrometry images (MSI) of intact cholesterol in a mouse esophagus tissue section and mouse zygotes. The VUVDI mass spectrum of the cholesterol standard shows dominant peaks from the parent molecules. In the case of the mouse esophagus tissue section, the ion images with a lateral resolution of ∼ 4 μm reveal that the cholesterol populates mainly in the mucosae. The experimental results indicate that the VUVDI method may provide a new MSI tool to measure the intact cholesterol in tissues and cells. [ABSTRACT FROM AUTHOR]

A novel photoluminescence lifetime probe (Ir-TB) has been developed for the detection and imaging of hCE2 in living cells. A large lifetime increase by around 300 ns after the enzymatic reaction makes it an ideal tool to distinguish hCE2-hydrolyzed probes from those non-hydrolyzed ones via PLIM for the first time. [ABSTRACT FROM AUTHOR]

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) based immunoassay method has been proposed in multiple immunoassays but has not been used in competitive and sandwich formats immunoassay simultaneously. The two immunoassays were usually conducted separately in clinical field depending on the size and the amount of binding sites of targets. We proposed an immunoassay method based on magnetic beads and ICP-MS detection that could be suitable for both small and large molecules. The functionalized magnetic beads were added to capture the immune complex after immune reaction. In this way, thyrotropin and free thyroid hormone can be captured, separated and then detected according to the elemental tags by ICP-MS simultaneously. The new method was evaluated by comparing the results with time resolved fluorescence immunoassays (TRFIA). The dynamic ranges of TSH and FT 4 were 0.16–105 mU/L and 3.5–65 pmol/L, respectively. The limits of detections were 0.06 mU/L for TSH and 1.59 pmol/L for FT 4 . And the relative standard deviations (RSD) of TSH and FT 4 were 4.64% at 2.5 mU/L and 1.87% at 5.85 pmol/L. This immunoassay method enables the determination of small and large biomolecules simultaneously via competitive and sandwich immunoassay formats. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a novel design that allows rapid online identification and quantitation of unsaturated fatty acid C=C location isomers via epoxidation and ambient mass spectrometry (MS). Unsaturated fatty acid solution was loaded on a paper strip placed between a low-temperature plasma probe and the inlet of a mass spectrometer. Reactive oxygen species in the plasma promoted epoxidation at the C=C, and the product was simultaneously ionized. Upon collision-induced dissociation (CID), the epoxidation product was fragmented to release diagnostic ions specific to the C=C location. The whole analytical workflow can be completed within 5 s and is particularly promising for point-of-care (POC) clinical diagnosis, considering its fast, high-throughput nature, and coupling with paper-based analytical devices. [ABSTRACT FROM AUTHOR]

A combinatorial immunoassay method for biomarker detection based on a stable isotope tagging strategy was proposed. A multiplex immunoassay of 12 proteins could be achieved simultaneously and a combinatorial immunoassay was explored, which would be expected to satisfy the requirements of personalized detection. [ABSTRACT FROM AUTHOR]

Designing probes for real-time imaging of dynamic processes in living cells is a continuous challenge. Herein, a novel near-infrared (NIR) photoluminescence probe having a long lifetime was exploited for photoluminescence lifetime imaging (PLIM) using an iridium-alkyne complex. This probe offers the benefits of deep-red to NIR emission, a long Stokes shift, excellent cell penetration, low cytotoxicity, and good resistance to photobleaching. This example is the first PLIM probe applicable to the click reaction of copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) with remarkable lifetime shifts of 414 ns, before and after click reaction. The approach fully eliminates the background interference and distinguishes the reacted probes from the unreacted probes, thus enabling the wash-free imaging of the newly synthesized proteins within single living cells. Based on the unique properties of the iridium complexes, it is anticipated to have applications for imaging other processes within living cells. [ABSTRACT FROM AUTHOR]