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Human milk oligosaccharides (HMOs) exhibit various biological activities for infants, such as serving as prebiotics, blocking pathogens, and aiding in brain development. HMOs are a complex mixture of hetero-oligosaccharides that are generally highly branched, containing multiple structural isomers and no intrinsic chromophores, presenting a challenge to both their resolution and quantitative detection. While liquid chromatography-mass spectrometry (LC-MS) has become the primary strategy for analysis of various compounds, the very polar and chromophore-free properties of native glycans hinder their separation in LC and ionization in MS. Various labeling approaches have been developed to achieve separation of glycans with higher resolution and greater sensitivity of detection. Here, we compared five commonly used labeling techniques [by 2-aminobenzamide, 2-aminopyridine, 2-aminobenzoic acid (2-AA), 2,6-diaminopyridine, and 1-phenyl-3-methyl-5-pyrazolone] for analyzing HMOs specifically under hydrophilic-interaction chromatography-mass spectrometry (HILIC-MS) conditions. The 2-AA labeling showed the most consistent deprotonated molecular ions, the enhanced sensitivity with the least structural selectivity, and the sequencing-informative tandem MS fragmentation spectra for the widest range of HMOs; therefore, this labeling technique was selected for further optimization under the porous graphitized carbon chromatography-mass spectrometry (PGC-MS) conditions. The combination strategy of 2-AA labeling and PGC-MS techniques provided online decontamination (removal of excess 2-AA, salts, and lactose) and resolute detection of many HMOs, enabling us to characterize the profiles of complicated HMO mixtures comprehensively in a simple protocol.

It is needed to speed up the development of a sensitive detection platform for simultaneous determination of dihydroxybenzene isomers with harmful properties. Here, two isomorphic Metal–organic frameworks (MOFs) [Zn(Trz)(R-BDC)1/2] (FJU-40-R, R = H or NH2; Trz = 1,2,4-Triazole; H-BDC = terephthalic acid) were selected to derive two N-doping porous carbon (NPC) materials. Further, a strategy for constructing electrochemical sensors for simultaneous determination of hydroquinone (HQ) and catechol (CT) was proposed by the MOF-derived NPC modifying glass carbon electrode (GCE). It was found that HQ and CT had good responses on NPC-FJU-40-H/GCE, but had no obvious responses on NPC-FJU-40-NH2/GCE. NPC-FJU-40-H/GCE displayed excellent reproducibility, stability, and anti-interference. Under the optimal conditions, the linear ranges of HQ and CT on NPC-FJU-40-H/GCE were 1 ~ 70 µmol L−1 and 1 ~ 100 µmol L−1 with the detection limits of 0.18 µmol L−1 for HQ and 0.31 µmol L−1 for CT, respectively. Although the porous carbon (PC) derived from MOFs has been applied in electrochemical sensing, the effect of the ligand functional groups of isomorphic MOFs on the electrochemical properties of the derived PC materials is still lack of relevant research. Our research provided an idea that the electrocatalysis properties of MOF-derived porous carbon materials could be tuned by changing the functional groups in ligands of isomorphic MOFs in electrochemical sensing field. A feasible strategy was proposed by changing the ligands of the two isomorphic MOFs (FJU-40-H and FJU-40-NH2) to tune the electrocatalysis properties of MOF-derived N-doped porous carbon materials for the simultaneous determination of dihydroxybenzene isomer.

A sensitive method based on cloud point extraction was developed for the separation and preconcentration of 12 phenolic compounds (hydroquinone, resorcinol, catechol, phenol, β-naphthol, bisphenol A, α-naphthol, 4-tert-butylphenol, 4-tert-octylphenol, nonylphenol, octylphenol, and 4-n-nonylphenol) from environmental water samples for subsequent analysis by high performance liquid chromatography. The nonionic surfactant Tergitol 15-S-7 was chosen as the extractant. The analytes were detected using a fluorescence detector. Gradient elution was performed with a mobile phase mixture of acetonitrile and water at a flow rate of 1.0 mL min− 1. Various experimental parameters affecting the analytical performance were optimized in detail. Under the optimum conditions, the correlation coefficients were all above 0.997 and the limit of detection range for the analytes was 0.03 to 8.5 μg L− 1. The proposed approach was successfully applied to the determination of 12 analytes in environment water samples with good recoveries (88.7%–106%).

Amine-functionalized Fe3O4@C nanoparticles with an average diameter of 266nm have been successfully synthesized by a solvothermal reduction method. The structure, morphology and properties of the Fe3O4@C nanoparticles were investigated through different analytical tools. Due to the magnetic nature and the presence of amine-functionalized groups, the as-prepared Fe3O4@C nanoparticles were employed as magnetic carriers for laccase immobilization. The results indicated that the loading of laccase onto the amine-functionalized Fe3O4@C nanoparticles was approximately 195mg/g. In comparison with free laccase, the pH, operational and storage stabilities of the immobilized laccase were significantly improved. After 10 consecutive operations, the immobilized laccase retained above 60% residual activity. The removal rates of o-phenylenediamine (OPD) by immobilized laccase were 88%, which were much higher than that of free laccase (50%). It hoped that the amine-functionalized Fe3O4@C nanoparticles may find an application in biotechnology and catalysis.

Diarylmaleic anhydride derivatives containing benzene (BPMA), thiophene (BTMA) and indole (BIMA) exhibit diverse and distinct fluorescence: aggregation-caused quenching (ACQ) of red emission of BIMA, blue aggregation-induced emission (AIE) of BPMA, and green dual-state emission (DSE) of BTMA in both solution and the solid state. Theoretical calculation and crystal structure analysis indicate that intramolecular and intermolecular interactions are responsible for their different emission behavior. A series of DSE-active molecules with full-color emission could be developed for the first time, through modification of the structures of BPMA and BIMA. Interestingly, BTMA and BPMA display multi-stimuli-responsive luminescence with a high-contrast (Δλem > 100 nm) and an unusual photochromic phenomenon in dichloromethane, which were utilized to construct rewritable data storage and mimic molecular logic operation (4-to-2 encoder and 1 : 2 demultiplexer), respectively.

A series of carbazole-based diphenyl maleimide dyes with different N-substituent were synthesized through an Ullmann reaction in high yields. The dyes exhibit an intense emission in the solid state for their twisted conformation fixed by weak intermolecular interactions, resulting in the hindrance of the internal rotations. Their solid-stated emission wavelength and intensity are sensitive to external stimuli (like heat, pressure and vapor), due to a crystal-to-crystal or crystal-to-amorphous phase transition. Based on the multi-stimuli-responsive fluorescence properties of the N-benzyl analogue, two kinds of applications were explored. One is rewritable data recording processes including solvent writing and vapor writing. The other is sensing for low hydrostatic pressure (0–25 MPa). Interestingly, nanoparticles of the dyes formed in aqueous solution could effectively detect explosive and pH changes. A 15 ppm concentration of picric acid quenched the fluorescence of the N-methyl analogue with the detectable limit calculated to be 0.13 ppm. The N-methyl analogue also showed a different emission color and intensity over the pH range 12–14, which originated from the hydrolysis of the dye molecules in the strongly basic solution.

A series of novel single white polymers, PFPMs and PFTMs, were designed and synthesized by introducing a green diphenylmaleimide (PM, λem = 500 nm) or yellow dithienylmaleimide (TM, λem = 557 nm) fluorophore guest into a blue polyfluorene (PF) host. By adjusting the feed ratio of the maleimide unit and fluorene unit, the resulting single white polymers exhibited a dual emission, including blue emission (415/439 nm) from PF and yellow (546 nm) or red (659 nm) emission from the PM or TM guest. The large red-shift in emission of the PM and TM in the backbone of the polymers originates from their conjugated structure being extended by the fluorene units. All the polymers show similar and high thermal stability and large solubility in common organic solvents. Their electroluminescent properties were investigated in single-emitting-layer devices fabricated by a solution process with the configuration of ITO/PEDOT:PSS/polymer/TPBI/LiF/Al. PFPM03, containing 0.3% PM, exhibited an excellent white electroluminescent performance for the effective and incomplete energy transfer from the PF host to the maleimide guest. The white device based on annealed PFPM03 at 140 °C for 30 min could be further improved to reach a maximal current efficiency of 8.14 cd A−1, power efficiency of 3.93 lm W−1, and external quantum efficiency of 3.78% with CIE coordinates of (0.34, 0.41).

Luminescent materials with aggregation-induced emission (AIE) have attracted extensive attentions for their strong emission in aggregated states. Although all kinds of AIE luminogens have been recently developed, it is difficult to realize full-color AIE which is popular for the various applications in optoelectronic fields. Herein, a class of diphenylfumaronitrile core-based dyes emitting in a wide region from near ultraviolet (382 nm) to near-infrared (682 nm) have been synthesized and well characterized. It is found that the emission wavelength of the dyes severely depends on the peripheral substituent, including electron-withdrawing trifluoromethyl (1), methyl (2), electron-pushing methoxyl (3), and bulky aromatic amine (7–9), and that the substituting location imposes great effect on the emission intensity of multiple-substituted dyes (4–6). Compound 4 with two methyl substituting at 3,4-position gives a ultrahigh quantum yield of 93% for unique packing structure. 1–3 and 7 can be used in explosive detecting and data storage for their emission sensitive to picric acid and external stimuli, respectively. When 4 and 8 applied in white-light-emitting diodes (WLEDs), a pure white emission can be obtained with 90 of CRI and (0.32, 0.32) of CIE.

A series of diarylmaleimide derivatives and polymers based on amide group were designed and synthesized to detect anions selectively and sensitively. Three bisindolylmaleimide derivatives (FAM-p, FAM-m and FAM-o) employing trifluoroacetamide as receptor exhibited strong fluorescent quenching upon fluoride and cyanide. Trifluoroacetamide receptor was replaced by acetamide to obtain other two derivatives (AM-p and AM-o) which showed higher selectivity than FAMs with sensing for only fluoride. The diarylmaleimide derivatives were introduced into the backbone of polyfluorene by Suzuki reaction to prepare polymer PFAM and PAM with same sensing selectivity for anions as FAM and AM, respectively. PFAM and PAM were found to be ratiometric fluorescence sensors for a fluorescence resonance energy transfer (FRET) from fluorene segments to diphenylmaleimide units. The experimental and DFT/TDDFT calculation results demonstrated that the interaction mechanism of FAMs with F− and CN− was hydrogen bond interaction and nucleophilic addition reaction, respectively.

The environmental pollution of 2,4,6-tribromophenol (TBP) has attracted attention. Based on an urgent need for the better provision of clean water, in situ determination of TBP is of great importance. Here, a facile and effective approach for detecting TBP is developed, based on coupling molecular imprinting technique with electrodeposition of chitosan (CS) on the gold electrode. The TBP imprinting CS film was fabricated by using CS as functional material and TBP as template molecule. The experiments show that the morphologies and electrochemical properties of the imprinted film sensor was different from non-imprinted film electrode. The current of the imprinted film was linearly proportional to the TBP concentration, with a wide linear range of 1.0 × 10−7 mol•L−1 to 1.0 × 10−3 mol•L−1. By selecting drop-coating method as a reference for controlled trials with the same functional material, the results illustrated that the electrodeposition enjoyed a widely linear range advantage.

2,4,6-Tribromophenol has been used as flame retardant and is a synthetic intermediate of the most important brominated flame retardants produced. In this work, a novel electrochemical sensor for determining 2,4,6-tribromophenol was fabricated by surface molecular imprinting technology, in which core–shell nanoparticles modified with (3-chloropropyl)trimethoxysilan and polyethylenimine were used as functional monomer, and 2,4,6-tribromophenol as template, ethylene glycol dimethacrylate as cross-linker. The electrochemical behavior the modified electrodes was investigated by electrochemical impedance spectroscopy and differential pulse voltammetry. The results showed that the imprinted electrode was significantly different from the non-imprinted electrode. The imprinted electrode had ascendant selective recognition ability, exhibited a low detection limit (1.51 × 10−8mol/dm3) and good repeatability (RSD is 4.35 % for 5 times) for the detection of 2,4,6-tribromophenol.

In this study, an ultra-sensitive method for the quantification of lysozyme based on the Gd(3+) diethylenetriamine-N,N,N',N″,N″-pentaacetic acid labeling and capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) was described. The Gd(3+)-tagged lysozyme was effectively separated by capillary electrophoresis (CE) and sensitively determined by inductively coupled plasma mass spectrometry (ICP-MS). Based on the gadolinium-tagging and CE-ICP-MS, the lysozyme was determined within 12 min with an extremely low detection limit of 3.89 attomole (3.89×10(-11) mol L(-1) for 100 nL of sample injection) and a RSD6% (n=5). The proposed method has been successfully used to detect lysozyme in saliva samples with a recovery of 91-106%, suggesting that our method is sensitive and reliable. The success of the present method provides a new potential for the biological assays and sensitive detection of low-abundant proteins.

The determination of brominated flame retardants is of great importance, but remains a challenge. Particularly, universal and facile approaches are limited. Here we report a new general approach, combining molecular imprinting and electrospinning, for the efficient and facile imprinting sensor of 2,4,6-tribromophenol (TBP), which was used as a “novel” brominated flame retardant. With TBP as the template molecular, β-cyclodextrin (β-CD) as the functional monomer, and poly-vinylbutyral (PVB) as the electro-spinning matrix, the nanofiber film was deposited on the glassy carbon electrode (GCE) via electrospinning technique directly. The β-CD-PVB/GCE sensor system exhibited excellent TBP sensing performances, such as a low detection limit (6.29 × 10−10 mol·L−1) at room temperature, selective recognition to TBP/phenol/4-methyl-phenol, and good regeneration performance. The approach of fabricating a molecular imprinting nanofiber sensor may shed new light in the detection of other phenolic pollutants.

Macroreticular p-(ω-sulfonic-perfluoroalkylated) polystyrene (FPS) resin with the advantages of both sulfonic polystyrene (such as macroreticular Amberlyst-15) and perfluoroalkanesulfonic resin (such as superacidic Nafion NR50) has exhibited excellent catalytic selectivity and activity in cyclization of pseudoionone and condensation of indole. In this paper, FPS was characterized by XPS, nitrogen sorption technique, FESEM and Hammett indicator method, and employed as the solid acid catalyst in the esterification, acylation and alkylation reactions. The FPS resin showed better activity than commercial solid acid catalysts (Amberlyst-15 and Nafion NR50) owing to its high surface area and strong acidity close to superacidity.

A new kind of ω -sulfonic-perfluoroalkylated poly(styrene–maleic anhydride)/silica hybrid nanocomposite FSMA/SiO 2 has been synthesized under mild conditions by perfluoroalkylation of styrene–maleic anhydride copolymer (SMA) with ω -fluorosulfonylperfluorodiacyl peroxides (SFAP), and followed in turn by aminolysis using (3-aminopropyl)triethoxysilane (APTES), alkali hydrolysis, gelation with tetraethoxysilane (TEOS) and finally acidification. The hybrid solid acid FSMA/SiO 2 with terminal perfluoroalkylsulfonic and carboxyl groups was characterized by FTIR, SEM, TEM, TGA, XPS, EDX, acidimetry and nitrogen sorption technique. Its pore structure, acid strength and acid amount were easily modulated by controlling the gelation and perfluoroalkylation conditions. The catalytic activity and selectivity, as well as reusability of FSMA/SiO 2 were tested in three important reactions, namely, cyclization of pseudoionone, condensation of indole and esterification of benzoic acid. Owing to the higher exchange capacity than that of Nafion/SiO 2 , and the stronger acidity than that of Amberlyst-15, the nanocomposite FSMA/SiO 2 showed higher activity and selectivity than these commercial solid acids in the reactions.

A facile solid state reaction route was employed to synthesize the ZnO/α-Fe 2 O 3 hierarchical nanostructures by grinding zinc acetate, α-Fe 2 O 3 and sodium hydroxide with proper molar ratios together at room temperatures without any surfactant and template. Their morphological feature was characterized as self-assembled by nanosheets on which α-Fe 2 O 3 nanoparticles were well sprinkled, and it was observed that the amount of α-Fe 2 O 3 added significantly affected the overall morphology. Furthermore, gas-sensing properties of the obtained products were studied. The results demonstrated that the sensors based on ZnO/α-Fe 2 O 3 hierarchical nanostructures exhibited a much higher sensitivity to ethanol vapor than the sensors based on pure ZnO nanostructures and the 2% α-Fe 2 O 3 -added ZnO/α-Fe 2 O 3 nanostructures sensors showed the highest sensitivity. Additionally, the mechanism of gas sensing was also studied.

A facile solution approach was employed to synthesize flower-like α-FeOOH precursors by using FeSO4·7H2O and CO(NH2)2 as raw materials at 80 °C for 6 h without any template and surfactant. After annealing in air at 500 °C for 2 h, the porous flower-like α-Fe2O3 superstructures were successfully obtained, whose morphological feature is characterized as self-assembled by porous nanorods with an average length of 0.1–1.0 μm and diameter of 50–150 nm. Transmission electron microscopy (TEM) images show that there are many porous walls with a pore size of about 10 nm on the surface. As a demonstration of potential application for gas-sensing materials, the porous flower-like superstructures exhibited short response/recovery time within 6/3 s, and presented a much higher gas response than α-Fe2O3 nanoparticles aggregations towards different concentrations of ethanol, methanol and acetone.

A facile approach for ultrasensitively sensing tris(2,3-dibromopropyl) isocyanurate (TBC) was reported. Based on coupling molecularly imprinting with electropolymerization of ο -phenylenediamine (OPD), which is electro-active monomers, the poly-OPD film was deposited in an OPD solution by potentiodynamic cycling of potential (scan rate is 50mV/s) on a glassy carbon electrode. Using K 3 [Fe(CN) 6 ] as an electro-active marker, the properties of the TBC imprinting electrode were investigated by differential pulse voltammetry and amperometric i-t curve and exhibited an excellent imprinting effect. The results showed that a linear relationship between the value of peak current and the TBC concentration was found in the range of 1.4×10 −12 ~6.7×10 −12 mol/L and a low detection limit of 6.26×10 −13 mol/L for TBC determination.