最新刊期
卷 31 ， 期 1 ， 2012
- 摘要：Molecularly imprinted polymer materials were prepared by bulk polymerization and precipitation polymerization methods using diazepam as template molecular，and effects of cross-linker，porogen agent and temperature on the properties of polymer materials were optimized.The molecularly imprinted micropheres were sythesized with divinylbenzene(DVB) as cross-linker and acetonitrile as porogen agent.The polymer prepared by bulk polymerization showed irregular shape，while the micropheres prepared by precipitation polymerization were regular in SEM image.The binding capacity and selective characteristics of the molecularly imprinted polymer were investigated by equilibrium binding experiments.It showed that the maximum adsorption to diazepam of the molecularly imprinted micropheres is up to 130 μg/g and the adsorption to oxazepam and nitrazepam is about 110 μg/g.The results showed that the imprinted polymer exhibited higher adsorptivity and selectivity for diazepam compared with the non-imprinted polymers.In addition，the molecularly imprinted polymer was used as solid phase extraction sorbent in solid phase extraction column to isolate diazepam in feed and pig urine samples for its excellent identifying characteristics.High performance liquid chromatography(HPLC) was imployed to detect three drugs.The method showed good linearities in the range of 0.1-20 mg/L for oxazepam,nitrazepam and diazepam，with correlation coefficients of 0.999 6-0.999 9 and detection limits(S/N=3 ) of 0.03-0.08 mg/L.The recoveries of three drug in feed and pig urine were in the range of 71%-79% and 66%-71%，respectively.The proposed method provides a new way for the detection of antipsychotic drugs.关键词：diazepam;molecularly imprinted;bulk polymerization;precipitation polymerization
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发布时间：2023-05-18 -
Isolation，Identification and Thermal Decomposition Behavior of Two Ionol Glucopyranosides in Tobacco
摘要：3-oxo-α-ionol-β-D-glucopyranoside and 7,8-dihyd-3-oxo-α-ionol-β-D glucopyranoside were isolated from flue-cured tobacco by traditional column chromatographic technology and high performance liquid chromatographic(HPLC) method.The structures were confirmed by ESI MS，1H NMR and 13C NMR.To develop thermally stable flavor，Py-GC-MS was used to measure the pyrolysis products at 300,600,900 ℃ in the helium environment.The main pyrolysis products were megastigmatrienones，3-oxo-α-ionol. The pyrolysis mechanisms of two glycosides were discussed.The thermal decomposition behavior of 3-oxo-α-ionol-β-D-glucopyranoside was firstly studied by thermal analysis coupled with IR and GC-MS(STA-IR-GC-MS) at 265 ℃.The results showed that STA-IR-GC-MS could be used to identify the main decomposition products of glucopyranosides conveniently and quickly.This method provides an accurate and quick way for the isolation and identification of thermal decomposition products of natural products.关键词：tobacco;glucopyranoside;isolate;identification;pyrolysis;STA-IR-GC-MS- 2299
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发布时间：2023-05-18 - 摘要：The aggregation behavior of surfactants in crowding consisted of polyethylene glycol (PEG) was investigated by using low-field nuclear magnetic resonance(LF-NMR).The data of different surfactant-PEG systems obtained from the CPMG sequence′s echo peaks and those inversed and fitted revealed that the molecular masses and concentrations of different PEG solutions could be distinguished by using low field nuclear magnetic resonance.The formation of micelles in PEG solutions with high concentration was observed，but it was not favorable for the observation of the process of micellization in the PEG solutions with low concentration.The existing of NaCl had obvious effect on the ionic surfactants system，but had hardly effect on the nonionic surfactants system.This research enriches the application of LF-NMR technology in the characterization of the process of micellization of surfactants and has a directive significance for understanding the self-assembly behavior and function of molecules in biological systems.关键词：low-field nuclear magnetic resonance(LF-NMR);polyethylene glycol(PEG);surfactant
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发布时间：2023-05-18 - 摘要：A nickel hydroxide-multi-wall carbon nanotubes modified ceramic carbon electrode(Ni(OH)2/MWNT/CCE) was fabricated by using surface coating method and cyclic voltammetry，and characterized by XRD technique and scanning electron microscopy(SEM).The electrocatalytic activity for glucose on the modified electrode was investigated by cyclic voltammetry and amperometric method.The results showed that the modified electrode exhibited a high electrocatalytic activity for the oxidation of glucose.Based on this，an amperometry technique for the determation of glucose was established.Under the optimum conditions，the oxidation peak current had linear relationships with concertration of glucose over the ranges of 2.0×10-7-5.7×10-4 mol?L-1(r=0.999 9 and 5.7×10-4-2.7×10-3 mol?L-1 (r=0.999 1)，with sensitivities of 2 786.5 μA?(mmol?L-1)-1?cm-2and 2 005.2 μA?(mmol?L-1)-1?cm-2，respectively.The detection limit (3sb) was 8.0×10-8 mol ? L-1.The proposed method was successfully applied in the detection of glucose in serum.关键词：nickel hydroxide;multi-wall carbon nanotubes;chemically modified electrode;glucose;electrocatalytic oxidation
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发布时间：2023-05-18 - 摘要：A method was developed for the simultaneous separation and determination of carbendazim，simazine，atrazine，chlorpyrifos，decamethrim,acetochlor and cypermethrin in corn and durra by micellar electrokinetic capillary electrophoresis.The conditions for separation and detection of a mixture of seven pesticides were optimized.The results showed that，under the optimized conditions of running buffer：20 mmol/L Na2HPO4+50 mmol/L SDS+5% acetonitrile（pH 9.0)，separation voltage：20 kV，detection wavelength：222 nm，ambient temperature:25 ℃，pressure injection：30 mbar×10 s，the analytes were successfully separated within 28 min.The calibration curves of seven pesticides were linear in the range of 5.0-150 μg?L-1.The detection limits were in the range of 0.6-3.0 μg/L.This method was successfully applied in the analysis of seven pesticides in corn and durra samples with spiked recoveries of 97%-108% and RSD of 2.2%-4.7%关键词：micellar electrokinetic capillary electrophoresis;pesticides;analysis;endocrine-disrupting chemicals
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发布时间：2023-05-18 - 摘要：An efficient method for the isolation and preparation of two anthocyanins，cyaniding 3-O-（β-D-giucopyranoside）（compound 1） and cyaniding 3-O-（6″-O-malonyl-β-D-glucopyranoside）（compound 2），from Echinacea purpurea flower by high speed counter-current chromatography（HSCCC） was established.The fresh flower was extracted with 60% ethanol（containing 0.1% HCl） at low temperature and dark conditions.2.1 g of crude sample for HSCCC was prepared after extracted with ethyl acetate and passed through an adsorbing column（2 cm× 30 cm，containing 100 mL D101 macroporous resin）.Then water-n-butanol-methyl tert-butyl ether-acetonitrile-trifluoroacetic acid（6∶3∶2∶1∶0.001） was used as the two-phase solvent system，in which the upper phase was used as the stationary phase，while the lower phase was used as the mobile phase，the flow rate was set at 2.0 mL/min，and the revolution speed was 850 r/min.9.8 mg compound 1 with purity of 95.1% and 14.3 mg compound 2 with purity of 98.2% were obtained from 160 mg crude sample by one-step，as determined by high-performance liquid chromatography（HPLC）.The chemical structures were identified by mass spectrometry（MS） and nuclear magnetic resonance imaging（NMR）.Additionally，the antioxidant activities of the two compounds were also evaluated by the method of 1,1-diphenyl-2-picrylhydrazyl（DPPH?） radical scavenging assay with Vc as the control group.The results of antioxidative activity test showed that the two compounds have strong capacity of scavenging DPPH（EC50＜10 mg/L）.Both of their EC50 were lower than that of Vc，and the scavenging ability of compound 1 was stronger than that of compound 2.关键词：high speed counter-current chromatography;Echinacea purpurea;anthocyanins;DPPH?;antioxidant activity
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发布时间：2023-05-18 - 摘要：An adsorption material of carbon-coated iron nanoparticles was synthesized by carbon arc discharge technology. The adsorption and elution behaviors of Cr，Ni，Cd and Pb ions on the above material were studied by inductively coupled plasma-atomic emission spectrometry.The results showed that the studied ions can be adsorbed quantitatively on the above material at pH 8.0-9.0 and the analytes adsorbed on carbon-coated iron nanoparticles can be eluted with acid solutions(pH=1.0-2.0).The detection limits of the method for Cr,Ni,Cd,Pb were 3.6，4.1，1.1,9.8 μg/L，respectively.The calibration curves were linear in the ranges of 1-500 μg/L for Cr，Ni，Cd and 10-1 000 μg/L for Pb，with correlation coefficients more than 0.999.The proposed method was applied in the determination of Cr,Ni,Cd,Pb ions in water sample and the recoveries reached 93%-105%.The adsorption capacities of carbon-coated iron nanoparticles for Cr，Ni，Cd and Pb ions were 3.6，4.8，6.3,2.1 mg/g，respectively.关键词：Carbon-coated iron nanoparticle;heavy metal;separation and concentration
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发布时间：2023-05-18 - 摘要：An Ultra Performance Liquid Chromatographic(UPLC） method was developed for the separation and determination of formaldehyde,acetaldehyde,acetone,acrolein,propionaldehyde,crotonaldehyde,2 butanone,butyraldehyde in cigarette mainstream smoke.The targeted compounds in cigarette mainstream smoke were collected with a Cambridge fliter treated with acidic solution of 2,4-dinitrophenylhydrazine, and extracted with 50 mL 2% pyridine acetonitrile.The carbonyl compounds were separated on a KinetexTM C18 (150 mm×2.1 mm,2.6 μm） column,using water-acetonitrile(35∶65） mixed solution and water-acetonitrile-tetrahydrofuran-isopropyl alcohol(59∶30∶10∶1） as mobile phases by gradient elution.The eight carbonyl compounds were separated in 20 min and determined by UPLC with a diode array detector.The result indicated that the correlation coefficients(r2） of eight carbonyl compounds were not less than 0.999 97.The detection limits for the method were between 25.81 ng/cig and 67.74 ng/cig.The average recoveries were in the range of 95%-99% with relative standard deviations of 1.4%-5.8%.Compared with the YC/T 254-2008 standard method, the proposed method was faster, simpler and less consumption, and was applied in the determination of eight carbonyl compounds in twenty kinds of cigarette with satisfactory results.关键词：cigarette;mainstream smoke;ultra performance liquid chromatography(UPLC）;carbonyl compounds
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发布时间：2023-05-18 - 摘要：The fluorescence characteristics of sulfasalazine（SASP） oxidized by potassium permanganate in sulfate acid medium were studied.The result indicated that SASP can react with potassium permanganate in sulfate acid medium to produce a strong fluorescent species（λex=301 nm，λem=366 nm）.Based on this phenomenon，a novel on-line oxidizing fluorescent method combined with flow injection technique was established for the determination of SASP.The experimental conditions affecting the fluorescence intensity of the system were investigated.The optimized experimental conditions were as follows: potassium permanganate concentration: 2.0×10-3 mol/L; sulfate acid: 2.0 mol/L; flow rate: 1.2 mL/min; length of mixing tube: 50 cm.Under the optimal experimental conditions，the calibration curves were linear in the range of 1.2×10-5-2.0×10-3 g/L with detection limit of 3.0×10-6 g/L.The relative standard deviation（RSD，n =11） was 0.6% for the determination of 1.2 ×10-4 g/L SASP standard solution.The proposed method had the advantages of simplicity，rapidity，high sensitivity and selectivity，and was successfully applied in the quantitative determination of SASP in enteric coated tablets with recoveries of 96%-107%.关键词：sulfasalazine;flow injection;on-line oxidizing;fluorescence analysis
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发布时间：2023-05-18 - 摘要：A novel method was developed for the determination of SiO2-3 in Cyclotella meneghiniana Kiits solution by non-suppressed conductance detection ion chromatography.The chromatography was performed on a Dionex anion AS23(4 mm×250 mm) analytical column and AG23(4 mm×50 mm) guard column with a constant temperature conductance detector.The experimental conditions were optimized，and the optimal chromatographic conditions were using 4 mmol/L sodium carbonate as eluent with a eluent speed of 1.0 mL/min，injection sample volume of 100 μL.The calibration curve of silicate was linear in the range of 0-40 mg/L.The detection limit was 0.017 mg/L.The relative standard deviation(RSD，n=7) for standard solution was lower than 5%.The RSDs for peak area and peak height measurements were 10.9% and 4.8%，respectively.The proposed method was applied in the determination of silicate in Cyclotella meneghiniana Kiits solution in different growing periods，and the spiked recoveries were in the range of 102%-120%.With the advantages of simplicity，good sensitivity，low cost，the method was suitable for the determination of silicate in cyclotella meneghiniana kiits solution.关键词：ion chromatography;non-suppressed conductance detection;silicate;diatom
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发布时间：2023-05-18 - 摘要：The scavenging activities，stabilities and hemi-inhibitory concentrations(IC50) of 4 flavonoids,including rutin，vitexin，kaempferide and hyperoside to DPPH free radical were investigated by UV-Vis spectra，by using natural antioxidants ascorbic acid as the comparison.The relations of the flavonoids structures with their antioxidant activities were also discussed.The results indicated that different antioxidants have different balance time in scavenging the DPPH free radical，in which rutin need the longest time.Four flavonoids and ascorbic acid have scavenging effect to DPPH free radical，and the dose-effect relationship exists.The DPPH free radical scavenging abilities of these five antioxidants were as follows:hyperoside＞ascorbic acid＞rutin＞kaempferide＞vitexin.The analysis on the structures of four flavonoids showed that the pyrocatechol hydroxy group of B ring was necessary for the antioxidant activities of flavonoids compounds.The hydroxymethylation of -OH at B ring and the glycosylation of -OH at A ring were not favorable for antioxidant activities.The glycosylation of 3-OH at C ring could increase the antioxidant activities of flavonoids,in which the antioxidant activity of monloglycoside(e.g.hyperoside) is better than that of diglycoside(e.g.rutin).关键词：flavonoids;DPPH free radical;structure-activity relationship
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发布时间：2023-05-18 - 摘要：A rapid determination method of the active xanthones in Garcinia mangostana was developed by supercritical fluid extraction rapid preparative chromatography-mass spectrometry.The active xanthones in Garcina mangostana were extracted by supercritical fluid extraction technology with alcohol as entrainer,and two xanthones,α-mangostin and gartanin,were separated from the crude extract through the device of rapid preparative chromatography and identified by mass spectrometry.The purity of two isolated compounds was not less than 90% via detection of HPLC/DAD.Meanwhile,the fragmentation mechanisms of two compounds were studied by electrospray ionization tandem mass spectrometry(ESI MSn).关键词：Garcina mangostana;xanthone;supercritical fluid extraction-rapid preparative chromatography-mass spectrometry
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发布时间：2023-05-18 - 摘要：A RP-HPLC method was developed for the enantiomeric separation of γ-schizandrin enantiomers on chiral column Chiralcel OD-RH(celulose tris(3，5-dimethylphenylcarbamate) coated on a 5 μm silica-gel substrate).Effects of mobile phase composition，flow rate and temperature on the separation of enantiomer were investigated.A baseline separation of γ-schizandrin enantiomers was achieved on a Daicel Chiralcel OD-RH column(150 mm×4.6 mm i.d.，5 μm) with methanol and water(90∶10) as mobile phase at flow rate of 0.5 mL/min.The column temperature was set at 20 ℃ and the detection wavelength was 254 nm，in which R-γ-schizandrin was firstly eluted.The Van-t Hoff plots of the lnk versus 1/T showed a good linearity with their correlation coefficients higher than 0.99.The thermodynamic parameters were calculated.The results indicated that the enantioseparation of γ-schizandrin enantiomers was typically enthalpy driven.The hydrogen bond,π-π and dipole dipole played significant roles in the enantiomeric separation of γ-schizandrin.关键词：γ-schizandrin;chiral separation;cellulose chiral solid phase;RP-HPLC
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发布时间：2023-05-18 - 摘要：A method was developed for analysis of thiocyanate（SCN-） pollutant in milk powder samples on an IonPac AS19 column using KOH gradient elution-ion chromatography/conductivity detection with a conductivity suppressor.The experimental conditions，including sample preparation，chromatographic conditions，were investigated. Under the optimal conditions，the calibration curve was linear in the range of 002-100 mg/L，with correlation coefficient（r） of 0.999 9.The limit of quantitation（LOQ，S/N=10） was 0.3 μg/g.The recoveries were in the range of 99%-102%.The method was reproducible，and the inter-RSD（n=7） for peak areas was 1.6% in the random detection of 2.0 mg/L standard solution in 3 d.关键词：thiocyanate;milk powder;ion chromatography;conductivity detection;food safety
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发布时间：2023-05-18 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometric(UPLC-MS/MS) method was developed for the simultaneous determination of spiramycin(e.g.spiramycin Ⅰ，SPM-Ⅰ) and neospiramycin(e.g.neospiramycin Ⅰ，NSPM-Ⅰ) residues in antibiotic production wastewater.The factors influencing the recoveries of antibiotics，including organic extractant type，water sample pH value，extraction time and ratio of water sample to organic extractant，were investigated.The target compounds were separated on an ACQUITY UPLC BEH C18 column(100 mm × 2.1 mm i.d.，1.7 μm) by gradient elution using 0.1% formic acid(A) and acetonitrile(B) as mobile phases at a flow rate of 0.2 mL/min.The qualification and quantification of target antibiotics were carried out by MS/MS with positive electrospray ionization under multiple reaction monitoring(MRM) mode.The calibration curves were linear over an antibiotic concentration range of 0.02-1.00 mg/L with correlation coefficients(r2) more than 0.999.The recoveries of antibiotics ranged from 70% to 88% with relative standard deviations(RSD，n=6) less than 10%.The detection limits(S/N=3) for SPM-Ⅰ and NSPM-Ⅰ were 0.03 μg/L and 0.06 μg/L，respectively.The developed method was applied in the determination of antibiotic production wastewater from a pharmaceutical manufacturing factory in Wuxi City，with SPM-Ⅰ of (115.6±2.7) mg/L and NSPM-Ⅰ of(5.3±0.4) mg/L.关键词：antibiotic production wastewater;spiramycin;neospiramycin;ultra performance liquid chromatography-tandem mass spectrometry
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发布时间：2023-05-18 - 摘要：In NH3-NH4Cl buffer solution(pH 9.3),terbium(Ⅲ) reacted with enoxacin (ENX) to form fluorescence coordinate compound with the maximum excitation wavelength of 330 nm and the maximum emission wavelength of 545 nm.The presence of SDS obviously strengthened the fluorescence intensity,but the fluorescence intensity of the complex was diminished by continuously adding celastrol,while the locations of the excitation and emission wavelengths were kept the same.Based on this,a new fluorescence method was proposed for the determination of celastrol.The method is simple,rapid and sensitive.The linear range of celastrol is 5.2×10-6-8.4×10-5 mol/L and the detection limit is 4.1×10-8 mol/L.关键词：celastrol;terbium;enoxacin;SDS;fluorescence quenching
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发布时间：2023-05-18 - 摘要：A novel PABSA modified glassy carbon electrode(PABSA/GCE) was fabricated by electropolymerizing PABSA on the surface of GC electrode.Morin can effectively accumulate on the electrode for the π-π stacking reaction between the aromatic rings of morin and the dimers of PABSA and cause an increased anodic peak signal.Based on this，a method was developed for the determination of morin.The electrochemical behaviors of morin on the modified electrode were investigated using cyclic voltammetry(CV) and differential pulse voltammetry(DPV) .The results showed that，in pH 7.0 PBS，morin generated a sensitive anodic peak at 0.214 V.Under the optimized conditions，DPV was used for detecting morin.The calibration curve was linear in the range of 5.0×10-7-1.0×10-3 mol/L，with a detection limit of 1.0×10-7 mol/L.The modified electrode，with the advantages of good stability，repeatability and wide linear range，was successfully applied in the determination of morin content in ramulus mori.关键词：poly(p-aminobenzene sulfonic acid);modified electrode;morin;electrochemistry
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发布时间：2023-05-18 - 摘要：A high performance liquid chromatographic method with fluorimetric detection was developed for the determination of six isocycanates in polymer material samples.The isocyanates in the polymer material samples were extracted with polar solvent and derivatived in the extraction system.The separation was performed on a C18 column using acetonitrile and triethylamine-phosphoric acid buffer as mobile phase by gradient elution.The external standard method was used for the quantitative analysis.Effects of extraction solvent,extraction methods,derivation time and compound of mobile phase on the separation efficiency were investigated.The results showed that polar extraction solvent dichloromethane and ultrasonic extraction were more suitable than nonpolar extraction solvent cyclohexane and shaking extraction.The optimal derivation time was 30 min.Under the optimal conditions,6 isocycanates were separated with a resolution more than 1.5.The calibration curves of 6 analytes were linear in the range of 10-100 μg/L with correlation coefficients not less than 0.999 1.The average recoveries of 6 isocycanates at the spiked levels of 0.1－1.0 mg/kg were in the range of 90%-95% with relative standard deviations(RSDs,n=5) of 2.2%-4.2%.The limits of detection(S/N=3) were in the range of 30.3 – 42.3 μg/kg for six isocycanates in polymer material.The proposed method was applied in the analysis of 4 kinds of polymer material and the results indicated that,except for phenyl isocyanate(PI),the other five isocycanates were found at different degrees in the practical polymer material samples with total concentrations of 79.7-326.3 μg/kg.This method was accurate,sensitive and highly reproducible,and was suitable for the analysis of residual isocycanates in polymer material.关键词：polymer material;isocycanates;high performance liquid chromatography;fluorimetric detection
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发布时间：2023-05-18 - 摘要：A method was established for the separation of complex and low content components in Houttuynia cordata Thunb by column-switching technology employing two reverse phase liquid chromatographic columns.A Synergi Fusion RP column and an Acclaim-120 C18 column with 250 mm×4.6 mm i.d.were adopted as the precolumn and analytical column，respectively.The precolumn was eluted with methanol -0.05% phosphoric acid as mobile phase.The analytical column was eluted with 0.05% phosphoric acid-acetonitrile.Three flavonoid components in Houttuynia cordata Thunb were simultaneously separated and detected.The calibration curves were linear in the concentration range of 10.0-1 000.0 mg?L-1，with correlation coefficient not less than 0.998.The recoveries of three compounds in Houttuynia cordata Thunb ranged from 95% to 99% with RSDs less than 3%.The results showed that the developed method was simple and rapid，and could be used in the analysis of flavonoid components.关键词：Houttuynia cordata Thunb;flavonoids;column switching;HPLC
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发布时间：2023-05-18 - 摘要：A sulfuric acid catalyzed esterification method was chosen for the determination of undecylenic acid(UA) and zinc undecylenate(ZnUA) in cosmetics.Effects of different operation parameters such as methyl esterification reagent，sulfuric acid concentration，water content in reaction system，reaction temperature and time were investigated.The result indicated that water content in reaction system had a great impact on esterification reaction.Under the optimal conditions，heated in 65 ℃water bath for an hour，UA and ZnUA were esterified with 5% sulfuric acid-methanol using n-hexane as extraction solvent.Methyl undecenoate was analyzed by GC with hydrogen ion flame detector(FID) and quantified by the external standard method.The yield of methyl undecenoate was calculated to be above 95%.The method had a good linearity in the range of 0.05-1.0 mg with correlation coefficient more than 0.999. The limit of detection(LOD) and the limit of quantitation(LOQ) of undecylenic acid were 0.001 2% and 0.004%，respectively.The average recoveries of UA in cream，lotion，toner and sanitizer were between 93% and 104% with relative standard deviations(RSDs) of 0.39%-5.1%.关键词：undecylenic acid;methyl esterification-GC/FID;cosmetic;preservatives
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发布时间：2023-05-18 - 摘要：A proton-nuclear magnetic resonance（1H NMR ） approach was presented for the determination of paracetamol in its tablet using potassium acid phthalate as the internal standard.Effects of some experiment parameters were investigated.The optimal conditions were selected as follows: relaxation delay time（D1 ）:1 s，pulse width（P1 ）:3 μs and transient number（NS）:16.The result indicated that，under the optimal conditions，the good repeatability for the method was obtained as the peak area ratios of inner standard potassium acid phthalate to sample paracetamol were all less than 0.4%.A good linear relationship between peak area ratio and weight ratio of inner standard potassium acid phthalate（δ7.44 ） to sample paracetamol（δ6.76 ）was obtained in the paracetamol concentration range of 2-10 g/L（the concentration of internal standard was about 6 g/L ），with correlative coefficient of 1.000 0.Three batches of real paracetamol tablets from different manufactures were determined by the method with standard curve and inner standard model，and the ultraviolet spectrophotometry method used in pharmacopoeia.The results indicated that two methods had no difference.关键词：1H NMR;paracetamol;quantification
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发布时间：2023-05-18
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