Construction of poly (styrene-divinylbenzene)@tris(4-aminophenyl)amine-p-phthalaldehyde-triethylenetetramine core-shell microspheres for the preparation of ion chromatography stationary phase.

Core-shell composite microspheres are increasingly favored for the development of stationary phases due to their ability to integrate the monodispersity of inner core with the functional versatility of outer shell. In this study, poly(styrene-divinylbenzene)@(tris(4-aminophenyl)amine-p-phthalaldehyde-triethylenetetramine) (PS-DVB@TAPA-PPA-TETA) core-shell composite microspheres were constructed via an amine-aldehyde condensation reaction. The resultant microspheres were subsequently quaternized using the residual amine groups of TETA in the shell to create an effective anion-exchange stationary phase.

Improving Triethylamine-Sensing Performance of WO Nanoplates through In Situ Heterojunction Construction.

Surface engineering techniques can be used to develop high-performance gas sensing materials and advance the development of sensors. In this study, we improved the gas sensing performance of two-dimensional (2D) WO nanoplates by combining surface Zn modification and the in situ formation of ZnWO/WO heterojunctions. Introducing Zn atoms by surface modification can reconstruct the atomic surface of 2D WO nanoplates, creating additional active sites.

Construction of amine-rich coating utilizing amine curing reaction of triglycidyl isocyanate with triethylenetetramine on the surface of poly(styrene-divinylbenzene) microspheres for preparation of anion exchange stationary phase.

Epoxy resins, as important thermosetting polymers, exhibit excellent adhesion to various substrates. In view of this, reticulate coating of triglycidyl isocyanate with triethylenetetramine was introduced onto the surface of poly(styrene-divinylbenzene) utilizing amine curing reaction to obtain poly(styrene-divinylbenzene)@triglycidyl isocyanate-triethylenetetramine composite microspheres. The amino groups and epoxy groups of triglycidyl isocyanate-triethylenetetramine endowed poly(styrene-divinylbenzene) with good reactivity, which could be quaternized under mild conditions to obtain an anion exchange chromatographic stationary phase.

Determination of behavior of catalpol hexapropionate in simulated gastric conditions by UPLC-ESI-HRMS.

Catalpol hexapropionate (CP-6) was designed and synthesized as anti-aging drug. In order to investigate the behavior of CP-6 in simulated gastric juice, ultra-high performance liquid chromatography-electrospray ionization-high resolution mass spectrometry was used to determinate the components produced in simulated gastric conditions. Six metabolites were identified with the possible metabolic processes proposed.

[Preparation and characterization of polyaniline/graphene-coated anion-exchange chromatographic stationary phase].

A polyaniline/graphene (PANI/G) composite was selected as the coating material to prepare a coated anion-exchange chromatographic stationary phase. First, aniline and graphene were used to prepare the PANI/G composite, which was coated onto the surface of poly(styrene-divinylbenzene) (PS-DVB) microspheres by physical absorption. Then, a series of anion-exchange stationary phases with different exchange capacities were obtained by quaternization using the nitrogen atom of polyaniline as the reactive site.

Determination and comparison of agarwood from different origins by comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry.

Agarwood, a species of resinous heartwood, is a precious medicinal plant and a type of rare natural spice, which is widely used in medicine, cosmetics, religious activities, and other fields. In this study, agarwood samples from eight different regions across four countries were analyzed by comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry. A total of 232 species were identified (the match factors of these compounds were above 750).

Silver Nanoparticles-Decorating Manganese Oxide Hybrid Nanostructures for Supercapacitor Applications.

A facile aerosol-based synthetic approach is demonstrated for the fabrication of silver-manganese oxide (Ag-MnO) and cetyltrimethylammonium bromide (CTAB)-templated silver-manganese oxide (c-Ag-MnO) hybrid nanostructures as the positive electrode materials of supercapacitors. Through gas-phase evaporation-induced self-assembly, silver nanoparticles are homogeneously decorated in the hybrid nanostructure to create a conductive path at the interface of the cluster of MnO crystallites. The utilization of the capacitance of MnO increases by the addition of Ag nanoparticles (>2 times for Ag-MnO and ∼1.

Fabrication of monodisperse poly (allyl glycidyl ether-co-divinyl benzene) microspheres and their application in anion-exchange stationary phase.

Micron-sized poly (allyl glycidyl ether-co-divinyl benzene) microspheres were prepared by a seed swelling and polymerization method and applied to prepare anion-exchange stationary phases by direct quaternization. The mono-dispersity, diameters, surface characteristics and porosity of microspheres were measured by scanning electron microscope and nitrogen adsorption-desorption measurements. The anion-exchange stationary phases were characterized by Fourier Transform Infrared Spectrum, Elemental Analysis, Breakthrough Curve, etc.

[Preparation and characterization of a latex-agglomerated anion exchange chromatographic stationary phase].

Allyl glycidyl ether (AGE) was selected as the copolymerization monomer to prepare a copolymer latex-agglomerated anion exchange chromatography stationary phase for ion chromatography (IC). First, allyl glycidyl ether-styrene (AGE-ST) copolymer latex was prepared by the saponification emulsion polymerization method. It was then quaternized by reacting alternatively with methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDGE) and agglomerated on the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) microspheres to obtain a copolymer latex-agglomerated anion exchange chromatography stationary phase.

Determination of γ-hydroxybutyrate in human urine samples by ion exclusion and ion exchange two-dimensional chromatography system.

A two-dimensional ion chromatography system was developed for the determination of γ-hydroxybutyrate (GHB) in human urine samples. Ion exclusion chromatography was used in the first dimensional separation for elimination of urine matrices and detection of GHB above 10mgL, ion exchange chromatography was used in the second dimensional separation via column-switching technique for detection of GHB above 0.08mgL.

[Modification of sol-gel hybrid monolith and its application in determination of polycyclic aromatic hydrocarbons].

A C6-silica hybrid monolithic column was prepared by click reaction with capillary silica monolith. Firstly, an azide-functionalized silica monolithic column was synthesized via sol-gel reaction with tetramethoxysilane (TMOS) and 3-azidopropyltrimethoxysilane (N3PTMS). Then 1-hexyne was covalently immobilized on the capillary monolith by the "azide-alkyne" click reaction to form C6-silica hybrid monolithic column.

Adaptive kernel independent component analysis and UV spectrometry applied to characterize the procedure for processing prepared rhubarb roots.

By determination of the number of absorptive chemical components (ACCs) in mixtures using median absolute deviation (MAD) analysis and extraction of spectral profiles of ACCs using kernel independent component analysis (KICA), an adaptive KICA (AKICA) algorithm was proposed. The proposed AKICA algorithm was used to characterize the procedure for processing prepared rhubarb roots by resolution of the measured mixed raw UV spectra of the rhubarb samples that were collected at different steaming intervals. The results show that the spectral features of ACCs in the mixtures can be directly estimated without chemical and physical pre-separation and other prior information.

[Extraction of spectral information of additives from activated manganese dioxide products using adaptive kernel independent component analysis].

The additives were abstracted from the manganese dioxide products with four kinds of organic solvents, ether, acetone, chloroform and toluene. The extracts were then baked and their attenuated total reflectance (ATR) FTIR spectra were measured using liquid membrane method. The number of chemical components of the additives was determined by median absolute deviation (MAD), and the spectral information of the pure component was extracted by kernel independent component analysis (KICA).

Multifunctional nanocomposites constructed from Fe3O4-Au nanoparticle cores and a porous silica shell in the solution phase.

This work is directed towards the synthesis of multifunctional nanoparticles composed of Fe(3)O(4)-Au nanocomposite cores and a porous silica shell (Fe(3)O(4)-Au/pSiO(2)), aimed at ensuring the stability, magnetic, and optical properties of magnetic-gold nanocomposite simultaneously. The prepared Fe(3)O(4)-Au/pSiO(2) core/shell nanoparticles are characterized by means of TEM, N(2) adsorption-desorption isotherms, FTIR, XRD, UV-vis, and VSM. Meanwhile, as an example of the applications, catalytic activity of the porous silica shell-encapsulated Fe(3)O(4)-Au nanoparticles is investigated by choosing a model reaction, reduction of o-nitroaniline to benzenediamine by NaBH(4).

Determination of endpoint of procedure for radix rehmanniae steamed based on ultraviolet spectrophotometry combination with continuous wavelet transform and kernel independent component analysis.

A method for determination of the endpoint of the procedure for radix rehmanniae steamed was proposed based on UV spectrophotometry combination with continuous wavelet transform and kernel independent component analysis (UV-CWT-KICA). In the proposed method, the raw UV spectra of the rehmanniae samples during steamed procedure were measured. The raw UV spectral data were firstly pretreated by CWT for elimination of the noise signal and enrichment of the spectral resolution, then the independent components (ICs) were estimated from the mixed CWT coefficient matrix.

[Determination of trace elements in tobaccos by microwave digestion/ICP-MS method].

2 mL 50% HNO3 and 1 mL 47% H2O2 were chosen for tobaccos digestion, and the acidity of final digestion solution was confined to about 2%. Standard solutions were diluted with 2% HNO3. The digestion solutions were determined by ICP-MS directly after adding internal standard elements Ge and Rh.

[Determination and comparison of metal elements in Huai radix rehmanniae at different grades by ICP-MS].

The Huai radix rehmanniae at different grades was pretreated by wet digestion, and then the metal elements in the radix rehmanniae and the prepared sample by steaming method were determined using ICP-MS. The results indicate that there is no obvious difference in the metal elements between the different grades and between the dried radix rehmanniae and its corresponding prepared product. There are elements Zn, Cu, Cr, Fe, Mn, Sn, Ni, Mo, Go, etc.

[Theoretical study on infrared vibration spectrum of catalpol by DFT].

The catalpol, which can be isolated from the Chinese traditional herbs Rehmannia glutinosa as an effective and active ingredient, is an iridoid glycoside with many pharmacological functions. The molecular structure and the infrared (IR) spectrum of catalpol were calculated using density-functional theory (B3LYP) at 6-311G** level, and the theoretical frequency was scaled by 0. 96.

Characterization of radix rehmanniae processing procedure using FT-IR spectroscopy through nonnegative independent component analysis.

A method is proposed for monitoring the radix rehmanniae proparate processing procedure and determining the endpoint of the process using attenuated total reflectance (ATR) FT-IR through nonnegative independent component analysis (ICA). In the proposed method, ATR FT-IR spectra of the samples were firstly measured at different steaming periods. Then, nonnegative ICA was used for direct estimation of the feature spectra of the pure components in the mixture without pre-separation and other prior information.

Characterization of volatile components in dry chrysanthemum flowers using headspace-liquid-phase microextraction-gas chromatography.

A headspace-liquid-phase microextraction (HS-LPME)-GC (gas chromatography) method for the characterization of volatile components in dry chrysanthemum flowers has been developed. In the proposed method, two extraction solvents, n-hexadecane and benzyl alcohol, are used for preconcentrating volatiles in the sample. A droplet of the extraction solvent is squeezed from the GC syringe and inserted in the headspace of the sample bottle with the dry flower, immersed in deionized water, and warmed in a water bath.

Estimation of source infrared spectra profiles of acetylspiramycin active components from troches using kernel independent component analysis.

Kernel independent component analysis (KICA), a kind of independent component analysis (ICA) algorithms based on kernel, was preliminarily investigated for blind source separation (BSS) of source spectra profiles from troches. The robustness of different ICA algorithms (KICA, FastICA and Infomax) was first checked by using them in the retrieval of source infrared (IR), ultraviolet (UV) and mass spectra (MS) from synthetic mixtures. It was found that KICA is the most robust method for retrieval of source spectra profiles.

Estimation of source spectra profiles and simultaneous determination of polycomponent in mixtures from ultraviolet spectra data using kernel independent component analysis and support vector regression.

A method that use kernel independent component analysis (KICA) and support vector regression (SVR) was proposed for estimation of source ultraviolet (UV) spectra profiles and simultaneous determination of polycomponents in mixtures. In KICA-SVR procedure, the UV source spectra profiles were estimated using KICA, then the mixing matrix of the components were calculated using the estimated sources, and the calibration model was build using SVR based on the calculated mixing matrix. A simulated UV dataset of three-component mixtures was used to test the ability of KICA for estimating source spectra profiles from spectra data of mixtures.

Characterization of the thermal decomposition and polymerization of arprocarb using pyrolysis-GC-MS.

Arprocarb is a carbamate type insecticide used to control cockroaches, flies, mosquitoes, and is a lawn and turf insect growth regulator. In order to evaluate the effects of the thermal behavior of arprocarb on its bioactivity or the environment, its thermal decomposition and polymerization were characterized using pyrolysis-GC-MS (Py-GC-MS). Arprocarb was pyrolysed at 450 degrees C, 600 degrees C, 750 degrees C, and 900 degrees C, respectively.

Determination and characterization of the pyrolysis products of isoprocarb by GC-MS.

The pyrolysis behavior of isoprocarb (an insecticide with contact and stomach action) is investigated using pyrolysis-gas chromatography-mass spectrometry. The pyrolysis products are separated using an HP-5 column under temperature program with helium as the carrier gas. The total of 80 separated pyrolysis components at 600 degrees C, 750 degrees C, and 900 degrees C under helium atmosphere are identified using a probability-based matching search procedure, combined with the correlation of boiling point (BP) and Lee retention index (RI).

Study of thermal behavior of vitamin D3 by pyrolysis-GC-MS in combination with boiling point-retention time correlation.

The thermal behavior of vitamin D3 was studied based on pyrolysis-GC-MS technique. It was pyrolyzed at 600 degrees C, 750 degrees C, 900 degrees C, respectively. The pyrolysis product were separated With an HP-5 column and identified by the NIST mass spectral search program in combination with the correlation of boiling point and retention time (BP-RT).