最新刊期
      卷 35 ， 期 11 ， 2016
      • Vol. 35, Issue 11, Pages: 1369-1375(2016)
        摘要：A new method was established for the authenticity identification of agarwood based on specific volatile components by solid-phase microextraction/gas chromatography-mass spectrometry(SPME/GC-MS).Odor components of agarwood were concentrated by SPME，and the chemical constitutions were detected by GC-MS.Relative contents of specific volatile components in odor components were determined by peak area normalization method.Authenticity identification was performed by comparing the species and relative contents in odor components of agarwood samples with specific volatile components of natural agarwood.The new method showed the advantages of low sample comsumption，simple operation，high sensitivity and accuracy，and was suitable for the determination of odor components and the authenticity identification of agarwood without damaging art collections.The new method was successfully applied in the authenticity identification of crude drugs and art collections of agarwood.  
        关键词：natural agarwood;component analysis;solid-phase microextraction(SPME);gas chromatography-mass spectrometry(GC-MS);authenticity identification analysis   
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      • Vol. 35, Issue 11, Pages: 1376-1383(2016)
        摘要：A separation and residue determination method for myclobutanil enantiomers in apple，grape and black tea was firstly developed by ultra performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry (UPC2-QTOF/MS).Samples were extracted with acetonitrile，purified with Cleaneert TPT or Cleanert PestiCarb solid-phase extraction(SPE) columns，and separated in the optimum condition of convergence chromatography，then analyzed by UPC2-QTOF/MS with the matrix external standard method.All the influence factors of convergence chromatography(chromatographic column，mobile phase modifier and proportion，column temperature，automated backpressure regulator，and post-column auxiliary solvent) were optimized.The best conditions were as follows: ChromegaChrial CCA column with a mobile phase of CO2-isopropanol(95∶5)，a flow rate of 2.0mL/min，an automated backpressure regulator(ABPR) of 13.79MPa，a column temperature of 30℃，and a post-column auxiliary solvent of methanol-water(1∶1) containing 2mmol/L ammonium formate. The results showed that the linear ranges of myclobutanil enantiomers were in the range of 0.01-1.00mg/L，and the correlation coefficients were above 0.98.The recoveries of myclobutanil enantiomers at three spiked levels of 0.005，0.025，0.25 mg/kg in fruit matrix were in the range of 62.5%-103.0% with relative standard deviations(RSDs，n=6) not more than 9.9%，and the limits of quantitation(LOQ) of enantiomers were 0.005mg/kg.The recoveries of myclobutanil enantiomers at three spiked levels of 0.01，0.05，0.5mg/kg in black tea matrix were 84.1%-86.4% with RSDs(n=6) less than 9.6%，and the LOQ for these two enantiomers were 0.01mg/kg.The method was rapid，convenient and reliable，and could meet the requirement for residue analysis.  
        关键词：chiral enantiomers;residual analysis;myclobutanil;ultra performance convergence chromatography(UPC2);quadrupole time-of-flight mass spectrometry(QTOF/MS)   
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      • Vol. 35, Issue 11, Pages: 1384-1389(2016)
        摘要：An oxidized graphene based magnetic nanoparticles(GO-Fe3O4) was synthesized by one step,and used as the adsorbent for the magnetic solid-phase extraction(MSPE) of six triazine herbicides in environmental water samples prior to high performance liquid chromatography with mass spectrometry(HPLC-MS/MS).The synthesized material was characterized by scanning electron microscopy(SEM) and Fourier transform infrared spectrometry(FTIR).Various experimental parameters including amount of GO-Fe3O4，extraction time， pH values and ionic strength of sample solution and desorption conditions were optimized to improve the extraction efficiency. The limits of detection of the method ranged from 0.1 ng/L to 1.0ng/L,and the enrichment ranged from 616 to 902 for six triazine herbicides. The method was applied in the analysis of actual water samples from Taihu lake，canal and moat in Suzhou，with spiked recoveries of 85.4%-117.6% and relative standard deviations(RSDs) of 1.2%-10.0%.Attributed to its simplicity and rapid operation，high enrichment and low detection limit，this method could be used to analyze the trace residues of triazine herbicides in water samples.  
        关键词：oxidized graphene based magnetic nanoparticles;magnetic solid-phase extraction(MSPE);trazine herbicide;high performance liquid chromatography-mass spectrometry(HPLC-MS/MS);environmental water sample   
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      • Vol. 35, Issue 11, Pages: 1390-1396(2016)
        摘要：A series of 598 pure polyester,pure cotton and polyester-cotton blended samples were selected by FT-MIR,and their relative contents were determined by the national standard method(GB/T 2910.11-2009).The samples original spectra were acquired by near-infrared(NIR)spectrometry，which were distributed into the calibration set(252 samples) and the validation set(346 samples).The best modeling spectra were obtained according to the size and trend range of regression coefficient distribution.Using preprocessing such as S-G smoothing，Differential 1st derivative and mean centering to analyze the samples NIRS，and the NIR quantitative analysis model for polyester-cotton blended fabrics was established by partial least squares(PLS) method.The influence of sample’s color on the NIRS was analyzed，and the effects of slash spectrum samples，singular samples and fabric stitch structure of samples on the prediction accuracy of the model were investigated. The result of experiment indicated that the NIR quantitative analysis model for polyester-cotton blended fabrics was established by PLS method，which included 1 spectral interval and 9 principal factors.The correlation coefficient of calibration and the standard errors of calibration were obtained to be 0.998 and 0.908,respectively.To verify the accuracy，validity and practicability of the model，346 bound samples were predicted. The variance analysis indicated that there was no significant difference between NIR method and national standard method，and the accurate recognition rate reaches up to 97%.The model will provide a foundation database for sorting the waste polyester-cotton blended fabrics quickly and non-destructively.  
        关键词：polyester-cotton blended fabrics;slash spectrum;singular samples;fabric stitch structure;near-infrared spectrometry(NIRS);quantitative model   
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      • Vol. 35, Issue 11, Pages: 1397-1402(2016)
        摘要：Topomer CoMFA was used to build a three-dimensional quantitative structure-activity relationship(3D-QSAR) model for 24 diarylaniline derivatives in this paper.The coefficient of cross validation,the coefficient of non-cross validation and external validation were 0.654,0.928 and 0.940，respectively. The result showed that this model had a good stability and a predictive ability. By using molecular docking,the action mechanism of drug and acceptor was studied, and the results showed that the drug functions obviously with LYS172，GLU138，LYS101 sites of HIV-1 reverse transcriptase. Based on the above informations,three new molecules of diarylaniline derivatives with high activity were theoretically designed,and the QSAR results could offer an atheoretical reference for the pharmaceutical synthesis.  
        关键词：3D-QSAR;topomer CoMFA;molecular docking;molecular design;diarylaniline derivatives   
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      • Vol. 35, Issue 11, Pages: 1403-1408(2016)
        摘要：According to the conversion of sRGB(Standard RGB) color space and CIE(Commission Internationale de L′Eclairage) colorimetric system and the character of the CIE 1931 chromaticity diagram,the MATLAB program was composed to achieve the conversion from the RGB information to the dominant wavelength or the complementary wavelength of one color,and then was utilized to analyze the images of the chromogenic products under the area light source.The quantitative detection of the pH value was realized with the color’s dominant wavelength and the detection of the nitrite with the color’s complementary wavelength.There are linear relationships between pH value and the color’s dominant wavelength of its chromogenic products in the pH value ranges of 4.0-7.0 and 7.5-10.0,respectively.And there is a favorable linear relationship between concentration(10-40 mg/L) of nitrite and color’s complementary wavelength of its chromogenic products.Combined with the Green value of the color,the range of detection by the traditional absorption spectrometry was enlarged.  
        关键词：dominant wavelength;program;pH value;nitrite;colorimetric analysis   
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      • Vol. 35, Issue 11, Pages: 1409-1415(2016)
        摘要：To screen feed for new or unexpected contaminants at the ppm level,a generic method was developed.The sample was extracted with 0.1%EDTA-acetonitrile-methanol (1∶1∶1,containing 0.1% formic acid) ,and analyzed by high-performance liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry(HPLC-Q-TOF/MS) in positive ionization mode.The data were collected after peak alignment (mass error within 50 mDa) ,noise filtration,elimination of useless peaks and statistical evaluation was performed based on Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) .According to the score plot,S-plot and VIP,blind statistical evaluation revealed that feed samples could be separated regarding unknown components by OPLS-DA and the m/z-retention time pair.With the assistance of MS/MS data,isotope abundance ratio,formula generation and self built spectral library,the structures of unknown compounds were confirmed.The results showed that 27 veterinary drugs were screened out from 16 feed samples.By quantitative analysis of 12 existing veterinary drugs using liquid chromatography tandem mass spectrometry(LC-MS/MS) ,only two false positives appeared in the verification results,and the concentration levels of 12 veterinary drugs were between 12.5 mg/kg and 152.0 mg/kg.From the perspective of the results,TOF-MS data and OPLS-DA could be applied in the non-targeted screening of veterinary drugs in feed samples with high accuracy.  
        关键词：liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS);non-targeted screening;orthogonal partial least squares discriminant analysis(OPLS-DA);feed;veterinary drugs   
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      • Vol. 35, Issue 11, Pages: 1416-1421(2016)
        摘要：A glass carbon electrode was modified with gold nanoparticles(AuNPs),graphene quantum dots(GQDs) and multi walled carbon nanotubes(MWCNTs) composite by dropping method.Firstly,GQDs were prepared using hydrogen peroxide as etching agent,then the gold nanoparticles-graphene quantum dots composite(AuNPs-GQDs) was prepared by in situ chemical reduction method and loaded on MWCNTs with poly dimethyl diallyl ammonium chloride(PDDA) as a crosslinking agent.The characterization of this composite was investigated by fluorescence spectrometry(MFS),UV-Vis absorption spectroscopy(UV-Vis spectra) and transmission electron microscopy(TEM).A glass carbon electrode modified wtih the composite(AuNPs-GQDs-PDDA-MWCNTs/GCE) was obtained with the dropping method.The electrochemical behavior of hydrogen peroxide on this modified electrode was investigated in detail.The results showed that this modified electrode had a high electrocatalytic activity for the oxidation of hydrogen peroxide under the synergic action of AuNPs,GQDs and MWCNTs.Under the optimum conditions,the linear range for the determination of hydrogen peroxide by amperometry was in the range of 2.0×10-8 – 1.5×10-3 mol/L,with a detection limit(3sb) of 8.0×10-9 mol/L and a sensitivity of 61.6 μA/(mmol?L-1).  
        关键词：graphene quantum dots;gold nanoparticles;multi walled carbon nanotubes;hydrogen peroxide;electrocatalysis   
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      • Vol. 35, Issue 11, Pages: 1422-1427(2016)
        摘要：A rapid method for the determination of nine haloacetic acids(HAAs) in wastewater effluent was established using reverse phase solid phase extraction pretreatment coupled with ultra-performance liquid chromatography-tandem mass spectrometry(RSPE UPLC-MS/MS).An ENVI-C18 cartridge was employed to remove organic substances in water sample to minimize its negative effect on HAAs analysis，and the pH value of sample was adjusted to 2.5 to eliminate the effect of inorganic ions on the ionization of HAAs.Under the optimal conditions，all the nine HAAs were separated within 15.0 min on a reversed phase liquid chromatographic column(HSS T3，2.1 mm×100 mm) using methanol-0.000 5% formic acid as mobile phase.The calibration curves were linear(r2=0.999 7-0.999 9) in the range of 0.5-100 μg/L for all the nine HAAs.The limits of detection(LODs) and limits of quantitation(LOQs) were in the range of 0.02-0.26 μg/L and 0.05-0.86 μg/L，respectively.The intra day and inter day relative standard deviations(RSDs) were in the range of 1.4%-10.0% and 1.7% -10.0%，respectively.The method recoveries ranged from 85.2% to 107.8% for effluent samples from three wastewater treatment plants at two spiked concentration levels of 2.5 μg/L and 10 μg/L.This method could meet the detection requirements for nine kinds of HAAs in wastewater effluents.  
        关键词：haloacetic acid;ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS);secondary effluent;solid phase extraction(SPE)   
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      • Vol. 35, Issue 11, Pages: 1428-1433(2016)
        摘要：Phenyl siloxane containing acrylate monomer was prepared through hydrosilylation of allyl methacrylate with 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane.The end groups of product were analyzed by nuclear magnetic resonance(1H-NMR).The specific structures with different end groups were analyzed by triple ultra performance liquid chromatography-time of flight mass spectrometry(UPLC-QTof-MS).And the results showed that there were three main components,including seperately 3-(5-methacryloyloxy-1,1,5,5-tetramethyl-3,3-diphenyltrisiloxanyl)-propyl-methacrylate，1,5-bis(γ-methacryloxypropyl)-1,1,5,5-tetramethyl-3,3-diphenyl-trisiloxane and 3-(1,1,5,5-tetramethyl-3,3-diphenyl-5-propyltrisiloxanyl)propyl methacrylate.In this paper，the qualitative analysis method of acrylate modified by silicone was established，which has an important guiding significance for its further development and reaction mechanism.  
        关键词：acrylate;silicone;modify;component analysis   
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      • Vol. 35, Issue 11, Pages: 1434-1439(2016)
        摘要：Three analytical methods were developed for the determination of hymexazol residues in 6 kinds of plant-derived agro-products(e.g.soybean，rice，cucumber，beetroot，cole and tomato) by gas chromatography with a flame photometric detector(GC-FPD)，gas chromatography with a nitrogen-phosphorus-detector(GC-NPD) and liquid chromatography tandem mass spectrometry(LC-MS/MS) ，respectively.In GC-FPD，samples were extracted with acetone-hexane.The extracts were derivated with dimethylthiophosphoryl(DECTP)，and then determined by GC-FPD，and quantified by the external standard method.In GC-NPD，samples were extracted with acetone-hexane.The extracts were purified with octadecylsilane(C18) sorbent，and then determined by GC-NPD，with quantitation by the external standard method.In LC-MS/MS，samples were extracted with acetonitrile.The extracts were purified with graphitized carbon black(GCB) sorbent，and then determined by LC-MS/MS with quantitation by the matrix matched calibrations.The calibration curves of three methods all showed good linearities，with correlation coefficients(r2) more than 0.998.At three spiked concentration levels，the inter day average recoveries of hymexazol were found to be in the range of 82%-96% for GC-FPD method with relative standard deviations(RSDs) of 34%-121%,81%-103% for GC-NPD method with RSDs of 4.1%-14.3% and 74%-110% for LC-MS/MS with RSDs of 2.5%-10.7%.In GC-FPD and GC-NPD，the limits of quantitation(LOQ) in beetroot were 0.05 mg/kg，and LOQs of other five matrices were 0.25 mg/kg.In LC-MS/MS，LOQs of 6 matrix were all 0.05 mg/kg.Three methods are accurate，and could meet the detection requirements of hymexazol residue in plant derived agro products.  
        关键词：hymexazol;GC-FPD;GC-NPD;LC-MS/MS;plant derived agro products   
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      • Vol. 35, Issue 11, Pages: 1440-1444(2016)
        摘要：A high performance liquid chromatography-tandem mass spectrometric method(HPLC-MS/MS) was developed for the simultaneous determination of hexabromocyclododecanes(HBCDs) and tetrabromobisphenol A(TBBPA) in farmland soils.Samples were extracted by accelerated solvent extraction(ASE) and purified with Sep-pak C18 solid phase extraction(SPE) cartridges.The targeted compounds were separated on an X Bridge C18(150 mm × 2.1 mm × 3.5 μm) using methanol-water as mobile phases,and then analyzed by HPLC-MS/MS in multiple reaction monitoring(MRM) mode with negtive electrospray ionization.The target compounds had good linear relationships(r≥ 0.998) in the range of 0.50-200.0 μg/L.The limits of detection(S/N ≥ 3) were in the range of 1.80-10.0 ng/kg,and the average recoveries at spiked levels of 1.0- 40.0 μg/kg ranged from 73.8% to 106.9%with RSDs of 5.8%-11.2%.The method was successfully applied in the detection of HBCDs and TBBPA residues in practical farmland soils.  
        关键词：words：accelerated solvent extraction(ASE);high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS);farmland soil;hexabromocyclododecanes(HBCDs);tetrabromobisphenol A(TBBPA)   
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      • Vol. 35, Issue 11, Pages: 1445-1450(2016)
        摘要：The stability of water-in-oil emulsion in oil based drilling fluid was investigated by low field NMR(low field nuclear magnetic resonance).Firstly,the transverse relaxation time T2 of white oil and pure water were obtained by the CMPG pulse sequence,then,a further qualitative analysis on the T2 distribution curve of water in oil emulsion was conducted by introducing the relaxation reagent MnCl2?4H2O,the relaxation peak located between 10 ms and 1 000 ms corresponded to the overlapping peaks of moderate movable free water and white oil,which was defined as emulsion relaxation peak.The relaxation peak located between 1 000 ms and 10 000 ms corresponded to that of the high degree movable free water.Thus,in this paper,the relaxation peak area ratio and relaxation peak spacing-were selected as quantitative indicators to investigate the influences of relaxation reagent,oil to water ratio and aging time on the transverse relaxation time T2 distribution curve of emulsion.In addition,low field NMR was also used to test the relative oil content in oil based drilling fluids emulsion.Experimental results showed that the low field NMR is an efficient,fast and accurate analysis technique to reflect the stability of oil-based drilling fluids emulsion,and it also could be used to test the relative oil content in oil-based drilling fluids emulsion or crude oil efficiently and accurately.  
        关键词：oil-based drilling fluids;emulsion droplet;low field NMR;transverse relaxation time   
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      • Vol. 35, Issue 11, Pages: 1451-1455(2016)
        摘要：A method based on ultrasonic assisted dispersive emulsion microextraction procedure coupled to high performance liquid chromatography with fluorescence detector(UA-DLLME-HPLC-FLD) was developed for the determination of nine fluorescent whitening agents (FWAs) residues in skincare water.Experimental conditions affecting the microextraction procedure such as type and volume of extraction solvent，content of disperse solvent，salt concentration，pH value，extraction time and centrifugal time were investigated.The ultrasonic assisted disperse emulsion microextraction conditions were optimized by using 50 μL chloroform as solvent and 250 μL methanol as disperser solvent，and the mixture was centrifuged at 4 500 r/min for 2 min.Under the optimum conditions，the calibration curves of nine fluorescent whitening agents in a certain concentration range with correlation coefficients more than 0.999 0.The limits of detection(LODs) of night fluorescent whitening agents ranged from 0.06 mg/kg to 4.20 mg/kg and the limits of quantitation(LOQs) ranged from 0.2 mg/kg to 14.0 mg/kg.The average recoveries for nine fluorescent whitening agents residues in skincare water were in the range of 84.3%-102.4%.Compared to the previous methods，the new procedure has the characteristics of simple sample preparation，low organic solvent consumption and high sensitivity.  
        关键词：dispersive liquid-liquid microextration(DLLME);ultrasound assisted(UA);high performance liquid chromatography(HPLC);fluorescent whitening agents(FWAs);skincare water   
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      • Vol. 35, Issue 11, Pages: 1456-1460(2016)
        摘要：In order to prepare the solid phase extraction column for the effective separation and enrichment of quercetin in the medicinal herb,a novel surface molecularly imprinted polymer was synthesized by a reversible addition fragmentation chain transfer(RAFT) polymerization method,combining molecular imprinting with living radical polymerization techniques,using acrylamide(AM) modified multi walled carbon nanotubes(MWCNTs) as supporting matrix，dibenzyltrithiocarbonate(DBTTC) as reversible RAFT reagent,quercetin as template molecule,methacrylic acid(MAA as functional monomer and acetonitrile as pore former.The multi walled carbon nanotubes molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy(FTIR),scanning electronic microscopy(SEM) and thermogravimetric analysis(TG).The adsorption properties and specific recognition ability of the polymer were tested by HPLC.The results showed that a stable imprinted layer was successfully grafted on the MWCNTs surface.And the imprinted polymers with good morphology and adsorption property have a specific recognition ability for quercetin.  
        关键词：living radical polymerization;multi-walled carbon nanotubes;molecularly imprinted polymer;quercetin;adsorption rate   
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      • Vol. 35, Issue 11, Pages: 1461-1465(2016)
        摘要：The silicon doped carbon quantum dots(SDCQDs) were synthesized using 3-aminopropyl trimethoxysilane(APTMS) and glutaraldehyde(GA) as mixed precursors.The maximum absorption wavelength，fluorescence excitation and fluorescence emission wavelengths of the SDCQDs were 259 nm，245 nm and 395 nm，respectively.The quantum yield of SDCQDs was 13.60%.The XPS spectra showed that the quantum dots were rich in azomethine group and silicon oxygen bond.The fluorescent intensity of SDCQDs could be quenched by copper ions.Hence，on the basis of the relationship between fluorescence quenching ratio and concentrations of copper ions，a method was developed for the determination of copper ions in water samples by using silicon doped carbon quantum dot as fluorescent probe.Other metal ions had no function of quenching.The spiked recoveries were in the range of 91.4%-100.8%，the detection limit was 0.13 μmol/L and the relative standard deviations(RSDs) were in the range of 0.20%-0.92%.  
        关键词：silicon doped carbon quantum dots;fluorescence quenching;fitting of S curve equation;copper ions   
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      • Vol. 35, Issue 11, Pages: 1466-1470(2016)
        摘要：A mixed binder containing liquid paraffin and silicone was blended with graphite powder to prepare a carbon paste electrode(CPE).Graphene/sodium dodecyl sulfate complex was used to modify carbon paste electrode to obtain a new modified carbon paste electrode(GR/SDS-CPE).Scanning electron microscopy and cyclic voltammetry were used to study the surface properties and electrochemical properties of the new modified carbon paste electrode，and the results showed that the specific surface area of GR/SDS-CPE was larger than that of CPE，so it is conducive to electron transfer.In pH 3.0 HAc-NaAc buffer solution，chloramphenicol(CAP) yields a sensitive oxidation peak with a potential of 0.194 V at the GR/SDS-CPE，and the oxidation peak current is 10 times larger than that at the CPE.Differential pulse stripping voltammetry(DPSV) showed that the oxidation peak current was linear with concentration of CAP in the range of 1.0×10-8-5.0×10-4 mol/L with a detection limit of 5.0 × 10-9 mol/L.With the advantages of simplicity，reproducibility and good selectivity，the method was applied in the determination of chloramphenicol eye drops and chloramphenicol residues in shrimp with satsfactory result.  
        关键词：carbon paste electrode;graphene;sodium dodecylsulfate;chloramphenicol   
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      • Vol. 35, Issue 11, Pages: 1471-1475(2016)
        摘要：A reversed phase high performance liquid chromatographic(RP-HPLC ) method for the simultaneous determination of rhynchophylline and isorhynchophylline in Uncaria Rhynchophylla was established by using ionic liquids as a mobile phase additive.With degree of separation and other related chromatographic parameters as indicators,the length of alkyl chain length and the type of anion in ionic liquid were selected.In addition,several influence factors,including imidazolium cation alkyl chain of ioinic liquids and concentration,mobile phase pH value and flow phase ratio were investigated.The probable mechanism of the separation with ionic liquids as mobile phase additives was also explored.The results showed that the longer the alkyl chain length of the cationic,the higher the separation efficiency of the anion,and the better the separation effect,that means the［HMIM］［BF4］ is the optimal mobile phase additive.The experimental results showed that when the ［HMIM］［BF4］ concentration is 16 mmol/L,the pH value of mobile phase is 3.0,and methanol ratio is 37%,baseline separations of rhynchophylline and isorhynchophylline were obtained, which could satisfy the requirements of sample separation.  
        关键词：ionic liquids;mobile phase additives;high performance liquid chromatography(HPLC);rhynchophylline;isorhynchophylline   
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      • Vol. 35, Issue 11, Pages: 1476-1480(2016)
        摘要：In this work，entropy minimization algorithms was used to deal with two GC-MS co-eluted peaks got from rose and Arabian jasmine essential oils，and the pure spectra of components inside co eluted peaks were obtained.Identification of those reconstructed components was done by NIST library matching，retention index comparison and MS fragments analyses.Two isomers’ pure spectra were found from each co-eluted peak from rose essential oil and Arabian jasmine essential oil.The results showed that the unknown isomers were successfully identified from the mixture spectra using the entropy minimization algorithm，and the study is very helpful for analyzing isomers in different mixtures.  
        关键词：chemometrics;co-eluted peaks;isomers;entropy minimization algorithms   
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      • Vol. 35, Issue 11, Pages: 1481-1485(2016)
        摘要：γ-Fe2O3/Ni2O3 composite nanoparticles coated with 2FeCl3?5H2O were obtained from the FeOOH/Ni(OH)2 precursor prepared by co precipitation and then processing in boiled FeCl2 solution.The composite nanoparticles processed in different concentrations of FeCl2 were investigated by vibrating sample magnetometer (VSM)，X ray diffraction(XRD)，transmission electron microscopy(TEM) and X ray photoelectron spectroscopy(XPS) techniques，and their microstructure and magnetic properties of composite nanoparticles were revealed.The experimental results showed that the magnetization of the as prepared products varied non monotonically as the FeCl2 concentration increased.The effects of FeCl2 concentration on magnetization，morphology and chemical composition of the as prepared products were investigated.  
        关键词：composite nanoparticles;FeCl2 solution;concentration;magnetic property   
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      • Vol. 35, Issue 11, Pages: 1486-1490(2016)
        摘要：A method for the rapid determination of 21 adulterants in anti rheumatic Chinese patent drugs or dietary supplements was established by HPLC using sub 3 μm fused core silica particles columns.The samples were extracted with 1% acetic acid methanol,and separated on the fused core column ACCHROM C18 100A (4.6 mm×100 mm,particle size 2.8 μm) column by gradient elution with a water solution of phosphoric acid (pH 3.0)-methanol-acetonitrile as mobile phase at a flow rate of 1.0 mL/min.The detection wavelengths were set at 230 nm and the column temperature was set at 35 ℃.Under the conditions,21 compounds could be separated within 20 min,and the calibration curve of naproxen showed a good linearity in the range of 1.5-30 μg/mL while those of the other 20 compounds were in the range of 5-100 μg/mL，and the detection limits(S/N=3) were 0.8 mg/kg for naproxen and 2.0 mg/kg for other compounds.The recoveries were between 91.0% and 1091%.The method was applied in the detection of real samples,and 18 positive samples were found.The samples were further confirmed by HPLC-MS/MS.The results indicated that this method was rapid and accurate,and could be used for the rapid determination of illegal adulteration in anti-rheumatic Chinese patent drugs or dietary supplements,which indicates its extensive application prospect.  
        关键词：anti-rheumatic;high performance liquid chromatography(HPLC);Chinese patent drugs;dietary supplements;adulteration   
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      • Vol. 35, Issue 11, Pages: 1491-1495(2016)
        摘要：A novel method based on sweeping under pseudo stationary state and micellar electrokinetic chromatography(MEKC) was developed for the determination of shellfish toxins in shellfish samples.The capillary was firstly pre filled with the running buffer containing sodium dodecyl sulfate(SDS).By adjusting pH value，the electrophoretic flow of SDS micelle was equal to the counter electroosmotic flow(EOF).The positive charged shellfish toxins were injected electrokinetically into capillary,swept and adsorbed with SDS micelle.The injection time was prolonged to 320 s under 10 kV since the SDS micelles were at a pseudo stationary state.With the sweeping under pseudo stationary state method，the preconcentration factors of 950 and 810 were obtained for saxitoxin and domoic acid，respectively，compared with the traditionally electrokinetic injection MEKC.The method was used to the quantitative determination of saxitoxin and domoic acid with their detection limits of 0.05 ng/mL and 0.12 ng/mL，respectively.The proposed sweeping under pseudo stationary state and MEKC method was successfully applied in the determination of two shellfish toxins in shellfish samples.  
        关键词：sweeping under pseudo stationary state;micellar electrokinetic chromatography(MEKC);shellfish toxins;shellfish samples   
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      • Vol. 35, Issue 11, Pages: 1496-1499(2016)
        摘要：Au@Pt NPs have an excellent peroxidase like activity，and silver ions(Ag+) could intensively inhibit the catalytic ability of Au@Pt NPs.Based on this，a colorimetric detection of Ag+ was performed in a linear range of 0.1- 10 nmol/L with a detection limit of 0.05 nmol/L.The sensing system also showed a sensitive response to Hg2+.A linear range of 10-200 nmol/L and a detection limit of 5.0 nmol/L were achieved in the colorimetric detection for Hg2+.The method was applied in detection of tap water spiked with Ag+(10，50,100 nmol/L)，and the recoveries ranged from 83.8% to 97.7% with relative standard deviations(RSD) of 3.0%-9.6%.This method has the advantages of simplicity，sensitivity and low cost.  
        关键词：Au@Pt nanoparticles;enzyme mimics;colorimetric detection;Ag+;Hg2+   
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      • Vol. 35, Issue 11, Pages: 1500-1504(2016)
        摘要：In this paper，a method was presented for the determination of formaldehyde in cosmetics based on a dual wavelength spectroscopy，in which both absorbances at 414 nm and 500 nm were used.The results showed that the relative standard deviation(RSD) of the method is only 0.46%，while it is 11.5% by the single wavelength method.The limit of quantitation(LOQ) of the dual wavelength method is 7.4 mg/kg.The present method is sensitive and accurate,and is suitable for the the determination of low content formaldehyde in cosmetic products.  
        关键词：cosmetics;formaldehyde;dual wavelength;visible spectrometry   
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      • Vol. 35, Issue 11, Pages: 1505-1512(2016)
        摘要：Ultraviolet absorbents are a kind of light stabilizers which have a strong absorption for ultraviolet light.They would cause harm to the environment and human health seriously.Many countries have formulated relevant laws and regulations to limit the use of ultraviolet absorbents.In this review，the recent researches about the determination technique and the research status of three types of ultraviolet absorbents including benzophenone，triazine and benzotriazole are summarized.The sample pretreatment and analysis technique are introduced，and the future development trend about the analysis of ultraviolet absorbents is also prospected.  
        关键词：ultraviolet absorbents;high concerned substances;benzotriazole;determination;review   
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