最新刊期
卷 33 ， 期 1 ， 2014
- 摘要：A gas chromatography（GC）-mass spectrometric（MS） method coupled with headspace solid phase microextraction（HS-SPME/GC-MS） was established to analyze 13 benzene series（BTEX） in seawater.The seawater samples were extracted by 100 μm polydimethylsiloxane（PDMS） fiber,and determined by GC-MS under selective ion mass mode with the external standard method.Several factors affecting the extraction efficiencies were optimized,including type of fiber,extraction temperature,extraction time,desorption time and sample volume.Under the optimized conditions,the linear equations were obtained in the concentration range of 0.16-32 μg/L with correlation coefficient（r） of 0.999 0-1.000 0.The limits of detection（S/N=3） were in the ranges of 0.006-0.043 μg/L.The recoveries at three spiked levels of 0.16,1.6,16 μg/L ranged from 80.0% to 117% with relative standard deviations（RSD,n=6） of 2.0%-5.6%.The proposed method was simple,sensitive,rapid and green,and was suitable for the determination of 13 BTEX in seawater.关键词：benzene series（BTEX）;headspace solid phase microextraction（SPME）;gas chromatography-mass spectrometry（GC-MS）;seawater;fast analysis
- 2362
- |
- 1749
- |
- 23
发布时间：2023-05-18 - 摘要：Microemulsion(W/O) formulations were prepared using lecithin as a surfactant,isopropyl myristate as the oil phase,n propanol as cosurfactant,and water.Influence of water content on the phase behavior of the microemulsion system was evaluated via the conductivity method,visual examination,dynamic light scattering(DLS) and differential scanning calorimetry(DSC).The results showed that,the microemulsion became cloudy when its water content was up to 11.5% in the visual examination.The conductivity increased slowly before water content reached 3.85%,and then followed a rapid increase until 10.71% at which the conductivity turned to decrease.The microemulsion droplet sizes assessed by DLS decreased firstly,and then increased as water content increased,the turning point was at 5.66%.After reaching 10.71% of water content,droplet sizes increased dramatically by three orders of magnitude.DSC curves revealed that microemulsion did not show water freezing peak until water content came up to 3.85%.With the increase of water content,the water freezing peak shifted towards high temperature and peak area increased linearly.However,the freezing peak divided into two at water content of 11.5%.Based on the study results,it could be deduced that phase structure transition point from W/O to Bi-continuous were in water content from about 3.85% to 5.66%,while the system was turned to phase separation at 10.71%.关键词：microemulsion;phase structure transition;DLS;DSC;conductometry
- 2264
- |
- 5817
- |
- 2
发布时间：2023-05-18 - 摘要：The feasibility of rapid detection of the process parameters such as moisture content and pH value in solid-state fermentation of Monascus was studied by near infrared technique.In view of the traditional wavelength selection methods based on interval strategy ignoring the disadvantages of the nonlinear factors,this paper adopted a new wavelength selection algorithm based on LS-SVM nonlinear model which was named synergy interval least squares support vector machines(siLS-SVM),and the new algorithm was compared with correlation coefficient method,iPLS algorithm and siPLS algorithm.The results showed that the combination of siLS-SVM and LS-SVM model achieved the best prediction result.The prediction correlation coefficients(Rp) of moisture content and pH value were 0.962 1 and 0.976 1,respectively.The root mean square errors for prediction set(RMSEP) were 0.012 9 and 0.145 2,respectively.The obtained results demonstrated that the fitting and the predictive accuracy were satisfactory,and it was feasible to apply NIRS method to fast determination of moisture contents and pH value in solid state fermentation of Monascus.This study provided a technical foundation for the further online detection of process parameters in solid-state fermentation of Monascus and the optimization of fermentation conditions.关键词：NIR;siLS-SVM;LS-SVM;Monascus;solid-state fermentation;moisture content;pH value
- 2469
- |
- 1754
- |
- 7
发布时间：2023-05-18 - 摘要：A liquid chromatography-tandem mass spectrometric(LC-MS/MS) method was developed for the simultaneous determination of olaquindox(OLQ) and carbadox(CBX) in animal originated foods(pork,chicken and fish).The CBX and OLQ were extracted with 0.1 mol/L sodium dihydrogen phosphate(NaH2PO4) solution(pH 6.0) and cleaned up with solid-phase extraction Oasis HLB column.The separation of compounds was carried on a Waters Xterra MS C18 column(5 μm,150 mm×2.1 mm) by gradient elution using acetonitrile-0.2%formic acid as mobile phase.The analyte was detected by tandem mass spectrometry under multiple reaction monitoring(MRM) mode with positive electrospray ionization.The CBX and OLQ were quantified by the matrix-matched external standard method.The results showed that the calibration curves of CBX and OLQ were linear in the range of 1-20 ng/mL with correlation coefficients of 0.998 1-0.999 9.The average recoveries of CBX and OLQ at spiked concentration levels of 0.2,0.4,2.0 μg/kg ranged from 70% to 93% with relative standard deviations(RSDs) of 1.9%-16.7%.The limits of quantitation(LOQ,S/N≥10) for two compounds were both 0.2 μg/kg.The established method was used for the determination of real samples(including pork,fish,chicken samples) and the result was compared with that of the national standard method.The result showed that the method was sensitive and accurate,and was suitable for the determination and confirmation of olaquindox and carbadox in pork,chicken and fish samples.关键词：olaquindox;carbadox;LC-MS/MS;animal originated food
- 3269
- |
- 3
- |
- 4
发布时间：2023-05-18 - 摘要：A method for the determination of histamine,tyramine,cadaverine,putrescine,tryptamine,spermine,spermidine and phenylethylamine in wines by liquid chromatography-quadrupole/electrostatic field orbit trap mass spectrometry was developed.The samples were diluted with deionized water,followed by dispersive solid phase extraction（DSPE） clean-up procedure with 200 mg octadecylsilyl（ODS） and 50 mg primary secondary amine（PSA）.Chromatographic separation was performed on a Phenomenex C18（100 mm×4.6 mm×2.6 μm） column with acetonitrile-0.1‰ heptafluorobutyric acid（HFBA） solution as mobile phase by gradient elution.Eight biogenic amines were analyzed in positive mode with ESI interface by quadrurpole/electrostatic field orbit trap high-resolution mass spectrometry.Accurate mass extraction for the target analytes and two-stage threshold-triggered mass improved the accuracy during the analysis.The linearities of 8 biogenic amines ranged from 0.2 mg/L to 10.0 mg/L with correlation coefficients more than 0.99.The limits of quantitation for 8 biogenic amines were all 1.0 mg/L.The average recoveries at three spiked levels（1.0,5.0 and 10.0 mg/L） were between 83.7% and 101.6% with relative standard deviations（RSDs） not more than 12.9%.The developed method was simple and sensitive,and could be applied as a screen and confirmatory method for the analysis of biogenic amines in red wines.关键词：biogenic amines;dispersive solid phase extraction;wine;quadrupole/electrostatic field orbit trap mass spectrometry
- 2613
- |
- 1746
- |
- 13
发布时间：2023-05-18 - 摘要：New carbon paste electrodes（HRP-MWCNTs-CILE） were prepared by using multi-walled carbon nanotubes（MWCNTs） and room temperature ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate（［EMIM］PF6） as binder.Then horseradish peroxidase（HRP） was modified on the surface of the electrode.The direct electrochemical characteristics of the modified electrodes were investigated by cyclic voltammetry（CV） and chronoamperometry（it）.A pair of approximate reversible redox peaks on CVs were observed in phosphate buffer.The enzyme electrodes showed good catalytic activity for hydrogen peroxide and good anti interference ability and stability.Under the optimal conditions,the biosensor showed a wide linear response to H2O2 in the range of 7.0×10-6-3.0×10-3 mol/L with a detection limit（S/N=3） of 2.5×10-6 mol/L.The sensor showed the characteristics of simple preparation,low cost,fast response and good application prospect.关键词：carbon paste electrode;multi-walled carbon nanotubes;horseradish peroxidase;hydrogen peroxide;ionic liquid
- 2224
- |
- 1514
- |
- 8
发布时间：2023-05-18 - 摘要：A high performance liquid chromatographic(HPLC)method combined with on-line clean-up and solid-phase extraction(SPE) was developed for the fast and effective determination of trace amount of vitamin B12(VB12) in beverages.A small change in the flow scheme of the traditional on-line SPE system reverses the flush direction on the SPE column，and creates an online SPE system with dual function(trapping the analytes and partially separating it from interferences prior to the analytical column) that eliminates interferences much more efficiently.The trapping of VB12 was completed by injecting 2.5 mL beverage sample into the SPE column(Thermo Scientific Acclaim PA Ⅱ，3 μm，3.0 mm×33 mm)，using phosphate buffer-acetonitrile as mobile phase,and then the VB12 was partially separated on the SPE column by changing mobile phase gradient.Therefore,only those interferences co-eluting with VB12 entered the analytical column，and more interferences were removed.The volume of VB12 cut from the SPE column was separated on the analytical column(Thermo Scientific Acclaim PA Ⅱ，3 μm，3.0 mm×150 mm) using phosphate buffer-acetonitrile as mobile phase，and detected with UV detector at 361 nm.The complete analysis only took 20 min.The relative standard deviation(RSD) of VB12 was 0.027% for retention time,and 2.2% for peak area.Good linearity was obtained in the range of 0.1-5.0 μg/L with correlation coefficient of 0.999 9.The spiked recoveries for 4 beverage samples were in the range of 91%-109%,and the limit of detection for this method was 0.046 μg/L.Compared with the direct large-volume injection and the traditional on-line SPE system,this method was better expression in easy manipulation and effective clean-up.关键词：on-line solid-phase extraction(SPE);on-line clean-up;dual-gradient high performance liquid chromatography(HPLC);valve-switching;beverage;vitamin B12
- 2973
- |
- 1602
- |
- 7
发布时间：2023-05-18 - 摘要：The interaction between bupropion hydrochloride and bovine serum albumin（BSA） was studied based on 1H nuclear magnetic resonance（1H NMR） chemical shift,Longitudinal relaxation time（1H T1）,2D nuclear overhauser spectroscopy（2D NOESY） and diffusion coefficient.The results showed that the presence of BSA could resulted in the significantly decrease in the chemical shifts of bupropion protons as well as the spin-lattice relaxation time,and the increase in the NOE cross peak.The apparent dissociation constant was 0.34 mmol/L and the binding sites of bupropion molecules on BSA was 11.Therefore,the reaction of bupropion and BSA was a combination of a number of weak points.The present study is of great importance for the safe and rational use of bupropion in clinic,and the development of improved bupropion analogs.关键词：nuclear magnetic resonance（NMR）;bupropion;relaxation time;2D NOESY;self diffusion coefficient
- 2239
- |
- 1613
- |
- 0
发布时间：2023-05-18 - 摘要：A method of supercritical CO2 fluid extraction gas chromatography-mass spectrometry (GC-MS) was developed for the determination of fragrance allergens in toy material.The optimal conditions were as follows:extraction temperature:50 ℃,pressure:300 bar;carbon dioxide flow rate:30 g/min; content of methanol entrainer:3%,dynamic extraction:30 min;static extraction time:30 min.Under the optimal conditions,the extracts were separated on a DB-17MS column,then determined by GC-MS and quantified by the internal standard method.The calibration curves were linear in the range of 0.02-60 μg/mL with correlation coefficients of 0.993 2-0.999 9 and detection limits(S/N=10) of 0.02-0.09 μg/mL.The average recoveries of the target compounds in polypropylene(PP),polyethylene(PE),alkyl benzo sulfonate(ABS) plastic samples were in the ranges of 79.6%-114.5%,75.0%-118.9% and 72.7%-114.9%，respectively.The relative standard deviations were in the ranges of 3.2%-11.0%,0.6%-11.6%,3.5%-11.0%.The results showed that this method was sensitive,reliable and environmental for the qualitative and quantitative determinations of fragrance allergens in toy product.关键词：supercritical carbon dioxide fluid extraction;gas chromatography-mass spectrometry;fragrance allergen;toy
- 2294
- |
- 1559
- |
- 5
发布时间：2023-05-18 - 摘要：dic and neutral NSO compounds in a petroleum reservoir core extract were characterized by negative-ion electrospray（ESI）-Fourier transform ion cyclotron resonance mass spectrometry（FT-ICR MS）.Heteroatomic species were characterized according to their class（number of nitrogen,oxygen and sulfur heteroatoms）,degree of aromaticity ［double bonds equivalent（DBE）］,and carbon number.The results showed that 16 heteroatom class species were identified in the extract,including N1,N1O1,N1O2,N1O3,N1S1,N1S2,N2,N2S1,O1,O1S1,O2,O2S1,O1S2,O2S2,O3 and O4 heteroatom classes.The N1,N1S1,O2 and O2S1 class species were abundant.For N1 species,the most abundant compounds were carbazoles and benzocarbazoles.For N1S1 species,the most abundant compounds were carbazole flanked on a thiophene ring of benzothiophene（DBE=14） with C2-C8 alkyls.The most abundant O2 class species were 1- and 2-rings naphthenic acids,high abundant O2 species with DBE values of 5 and 6 were also identified.In addition,the O2S1 class species with DBE values of 7 and 8 were the most abundant.关键词：rock extracts;polar compounds;ESI;FT-ICR MS
- 2969
- |
- 1611
- |
- 4
发布时间：2023-05-18 - 摘要：A preparative high performance liquid chromatographic(PHPLC) method was established for the simultaneous preparation of six soybean isoflavones monomers with high purity from soybean crude extracts purified with macroporous adsorption resin.The effects of experimental conditions,including mobile phase composition,flow rate and sample quantity on resolution were investigated on a SHIM-pack PRC-ODS preparative column(20 mm×250 mm,5 μm).The optimal conditions were as follows:mobile phase:acetonitrile-water by gradient elution,injection volume:800 μL,flow rate:10 mL/min.Under the optimal conditions,the baseline separation and preparation of six isoflavones monomers were achieved within 120 min.Six compounds were identified by ultra high performance liquid chromatography-tendem mass spectrometry (UPLC-MS/MS) to be daidzin,glycitin,genistin,daidzein,glycitein and genistein with purities of 95.54%,90.14%,100%,100%,96.27% and 100%,respectively.With the benefits of simplicity,good stability and high products purity,the developed method show a good application prospect in the production of soybean isoflavones standard materials.关键词：soybean isoflavones;monomers;preparative high performance liquid chromatography (PHPLC);UPLC-MS/MS
- 2313
- |
- 3
- |
- 6
发布时间：2023-05-18 - 摘要：After cellulose was dissolved in a mixture of N,N-dimethylacetamide-LiCl-pyridine mixed solution,it was directly coated onto γ-aminopropyl silica gel,then immobilized onto silica gel using 4,4′-diphenylmethane diisocyanate and hexamethylene diisocyanate as the spacer,respectively,and finally reacted with an excess of 3,5-dimethylphenyl isocyanate.Thus,two immobilized-type chiral stationary phases（CSPs） based on cellulose 3,5-dimethylphenylcarbamate were prepared and evaluated for HPLC enantioseparation.The results showed that the obtained CSPs exhibited high chiral recognition ability and solvent durability.Many of the tested racemates could be well resolved when using eluents containing chloroform or tetrahydrofuran instead of the conventional eluent（e.g.hexane-isopropanol mixture）.In addition,interfences on the chiral recognition of CSPs due to different diisocyanates could be negligible.关键词：chiral stationary phases;polysaccharide derivatives;immobilization;chiral recognition;chiral separation
- 2177
- |
- 1631
- |
- 1
发布时间：2023-05-18 - 摘要：Based on magnetic beads as separating carrier and adenosine as a specific competitor appeared，a method of aptamer-based chemiluminescence(CL) for the determination of adenosine was developed.Experimental parameters including magnetic beads,adenosine-aptamer and report DNA were optimized.Under the optimal conditions，the decreased CL intensity was proportional to the adenosine concentration in the range of 1.0×10-9-1.0×10-4 mol/L(r2=0.99)，with a detection limit of 1.0×10-9 mol/L.The relative standard deviation(n=5) for 0.1 mmol/L adenosine is 5.0%.The present method was successfully applied in the determination of adenosine in real human urine.The method is simple，sensitive and specific for the detection of adenosine，and it is a promising approach for the determination of small biomolecules in the fields of clinical diagnosis，pharmaceutical analysis and so on.关键词：chemiluminescence;adenosine;aptamer;magnetic bead;horseradish peroxidase
- 2358
- |
- 1649
- |
- 4
发布时间：2023-05-18 - 摘要：A method for the determination of emamectin benzoate by ultra-performance liquid chromatography coupled with tandem mass spectrometry（UPLC-MS/MS） was developed.The analytes were extracted using ethyl acetate,and cleaned with PCX column.The column eluents were extracted by ethyl acetate again.The extracts were blown to nearly dry by nitrogen,then dissolved in methanol.The sample solutions were separated on a BEH C18 column（50 mm×2.1 mm,i.d.1.7 μm） using a gradient elution program of aqueous solution containing acetate and ammonium acetate.Qualitative and quantitative detections of the analytes were carried out under the multiple reaction monitoring（MRM） mode by MS with electrospray in positive ionization.The method had a good linear correlation（r≥0.999） in the range of 1-200 μg/L.The recoveries of emamectin benzoate at spiked level of 0.1-50.0 μg/kg were in the range of 70%-110% with relative standard deviations（RSDs） of 0.3%-15.9%.The limit of quantization（LOQ） was 0.1 μg/kg.There were significant matrix suppression effects in soil samples and rice straw samples,but matrix enhancement effect occured in water samples.关键词：emamectin benzoate;ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）;residue;paddy rice
- 2325
- |
- 1756
- |
- 2
发布时间：2023-05-18 - 摘要：A balance pressure static headspace sampling gas chromatographic method was developed for the determination of HCH and DDT pesticide residues in the transgenic soybean oil using a typical mixed ionic liquids of ［Bmim］PF6-［Bmim］BF4 by a ratio of 1∶2 as a headspace solvent,based on that mixed ionic liquids have the characteristics of low vapor pressure,high boiling point,excellent dissolving ability,good hydrophilicity and hydrophobicity at the same time.Experimantal conditions,including type of ionic liquid,proportion and dosage of ionic liquid,headspace equilibration temperature,headspace equilibration time and headspace sampling time were optimized.The results showed that the calibration curves were linear in the range of 5-100 μg/L,with correlation coefficients of 0.990 5-0.999 6.The detection limits and quantitation limits of 8 pesticides were in the range of 1.4-15.2 μg/kg and 4.7-48.6 μg/kg,respectively.The recoveries and RSDs were 72.3%-104.1% and 0.6%-7.8%,respectively.The method was rapid and accurate,and could be uesed to avoide for the complicated sample pretreatment process.关键词：mixed ionic liquids;headspace;transgenic soybean oil;hexachlorocyclohexane（HCH）;dichlorodiphenyltrichloroethane（DDT）
- 2401
- |
- 1663
- |
- 5
发布时间：2023-05-18 - 摘要：A new biosensor was fabricated with sol of nanosilver/chitosan（sol-AgCS） and acetylene black（AB） to form a compound film on a glassy carbon（GCE） electrode.The AgCS was characterized by UV spectrometry and scanning electron microscopy（SEM）.The different GCEs were characterized by electrochemical impedance spectroscopy（EIS）.The electrochemical behaviors of ethyl naphthol（β-N） on AgCS-AB/GCE were investigated by cyclic voltammetry（CV）.The results showed that β-N exhibited a sensitive oxidation peak in pH 6.5 PBS buffer solution.The oxidation peak current（Ipa） was linear to v1/2 in the range of 60-240 mV/s,which suggested that the electrode process of β-N was controlled by diffusion.The reaction electronic numbers,diffusion coefficient and other important parameters of β-N were calculated.The different concentrations of β-N were determined by square wave voltammetry,and a good linearity between peak current and concentration of β-N was observed in the range of 3.0×10-7-2.0×10-4 mol/L.The detection limit（S/N= 3） was 1.24×10-7 mol/L and the spiked recoveries were in the range of 99%-105%.关键词：ethyl naphthol;acetylene black;nano-silver;SEM;square wave voltammetry
- 2482
- |
- 1642
- |
- 1
发布时间：2023-05-18 - 摘要：A simple and rapid method was developed for the simultaneous determination of 11 fat-soluble colorants,including Sudan Orange G,Dimethyl Yellow,Para Red,Citrus Red 2,Sudan Red G,SudanⅠ,SudanⅡ,Sudan Ⅲ,Sudan Red 7B,Sudan Red B and Sudan Ⅳ in chilies.The sample was extracted with ethyl acetate and then purified by gel permeation chromatography（GPC）.The targeted compounds were detected by HPLC/DAD detector and quantified by the external standard method.The calibration curves of 11 colorants were linear in the range of 20-1 000 μg/L with correlation coefficients more than 0.998 .The average recoveries of 11 colorants at three spiked levels of 10,20,40 μg/kg were between 75.8% and 90.8%,with relative standard deviations of 3.0%-7.8%.The quantitation limits（S/N≥10）were all 10 μg/kg.The method is convenient and accurate,and could be applied in the determination of 11 colorants in chilies and chili sauce.关键词：gel permeation chromatography（GPC）;high performance liquid chromatography（HPLC）;diode array detection（DAD）;colorants;chilies
- 2761
- |
- 1827
- |
- 6
发布时间：2023-05-18 - 摘要：The electrochemical behaviors of tetrandrine at glassy carbon electrode as well as its interaction with DNA were studied using cyclic voltammetry,differential pulse voltammetry,controlled potential electrolysis and ultraviolet-visible spectroscopy.The results indicated that the electrochemical oxidation of tetrandrine was an irreversible process and the electrode process was controlled by the diffusion step,and the parameters of electrochemical kinetics were investigated.The results showed that the electrode process of tetrandrine on glassy carbon electrode was two electrons and two hydrions transfered,and the electron transfer coefficient was 0.62.In the presence of DNA,the oxidation current of tetrandrine was decreased considerably,and the peak potential was shifted to the positive direction,which suggested that the binding of tetrandrine to DNA was via intercalation.The association constant（β） and stoichiometric coefficient（m） were calculated to be 4.27×103 and 1,respectively.关键词：tetrandrine;DNA;electrochemistry;interaction
- 2322
- |
- 1705
- |
- 1
发布时间：2023-05-18 - 摘要：A solid-phase extraction and capillary gas chromatographic method was developed for the determination of BHC & DDT pesticide residues in cinnamomum cassia bark.The pesticide residues were extracted by vortex oscillation using acetone-petroleum ether mixed solvent as extraction agent,and the extract was purified by solid-phase extraction technology.The proportion and dosage of the elution solvent were optimized,and the detection of targeted compounds was performed by GC/μECD.Under the optimal conditions,the calibration curves were linear in the range of 10-1 000 μg/L ,with correlations coefficients of 0.995 8-0.998 1.The average recoveries for BHC and DDT were in the range of 92.1%-112% with RSDs（n=5） of 2.8%-8.1%.The limits of detection（LODs） were 5.0×10-3-2.4×10-2 mg?kg-1，and the limits of quantitations（LOQs） were 1.3×10-2-6.0×10-2 mg?kg-1.The method was simple，sensitive,accurate and reproducible.关键词：cinnamomum cassia bark;BHC;DDT;pesticide residues;solid-phase extraction;capillary gas chromatography
- 2475
- |
- 1745
- |
- 5
发布时间：2023-05-18 - 摘要：ethyl carbamate; soy sauce; vinegar; gas chromatography-mass spectrometry(GC-MS); dispersive solid phase extraction(d-SPE)关键词：ethyl carbamate;soy sauce;vinegar;gas chromatography-mass spectrometry(GC-MS);dispersive solid phase extraction(d-SPE)
- 2610
- |
- 3
- |
- 5
发布时间：2023-05-18 - 摘要：Triacylglycerols(TAGs) profiling of plant oils is important for the effective control of edible oil quality and the safety assurance of plant oils.The analysis of TAG compositions in plant oils is a challenging task because of the complicated compositions of TAGs and their similar physico-chemical properties in plant oils.In this article,all kinds of chromatography technologies for the analysis of TAGs were reviewed.The advantages and disadvantages of these analytical methods and the relevant applications in TAGs analysis were also described.In addition,the applications of fingerprint technique and chemometrics methods in the identification of plant oils were also introduced.关键词：edible plant oil;triacylglycerols;chromatography;fingerprint technique;chemometrics;development progress
- 2281
- |
- 1567
- |
- 12
发布时间：2023-05-18
- Address：100 Xianlie Middle Road, Guangzhou Postal code：510070
- Tel：020-87684776,37656606 Fax：020-87684776 Email：fxcsxb@china.com
- Technical support is provided by Beijing Founder electronics co., LTD 粤ICP备12017312号-3
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0