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2008 Volume 25 Issue 4
2008, 25(4): 381-384
Abstract:
Polystyrene microspheres with an average diameter of 55 μm were prepared by suspension polyme-rization via oxidation of the monomer by ammonium persulfate.Poly-3-aminophenylboronic acid was grafted onto the surfaces of the polystyrene microspheres to form polystyrene/poly-3-aminophenylboronic acid coreshell micospheres.The samples were characterized with scanning electron microscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and nitrogen adsorption/desorption method.The results show that poly-3-aminophenylboronic acid was successfully grafted to the surfaces of the polystyrene microspheres by aromatic ring electron-pairing interaction,and that the surfaces of the core-shell microspheres possessed porous structure,with the average pore diameter of 30.2 nm and the BET surface area of 193.26 m2/g.
Polystyrene microspheres with an average diameter of 55 μm were prepared by suspension polyme-rization via oxidation of the monomer by ammonium persulfate.Poly-3-aminophenylboronic acid was grafted onto the surfaces of the polystyrene microspheres to form polystyrene/poly-3-aminophenylboronic acid coreshell micospheres.The samples were characterized with scanning electron microscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and nitrogen adsorption/desorption method.The results show that poly-3-aminophenylboronic acid was successfully grafted to the surfaces of the polystyrene microspheres by aromatic ring electron-pairing interaction,and that the surfaces of the core-shell microspheres possessed porous structure,with the average pore diameter of 30.2 nm and the BET surface area of 193.26 m2/g.
2008, 25(4): 385-390
Abstract:
In a Britton-Robinson buffer solution (pH 4.0~5.2),sodium alginate (SA) can be bound with some basic bisphenylnaphthylmethane dyes such as Victoria blue 4R(VB4R),Victoria blue B(VBB),or night blue (NB) to form a new product,resulting in a significant enhancement of Resonance Rayleigh Scattering (RRS) and the appearance of a new RRS spectrum.The RRS intensity was directly proportional to the SA concentration in a range of 0.075~4.0 mg/L for all the systems,which showed that the method has a fairly high sensitivity.The detection limits of SA (3σ) were 22.0×10-9 g/mL for VB4R-SA system,25.6×10-9 g/mL for VBB-SA system,and 37.5×10-9 g/mL for NB-SA system,respectively.The VB4R system exhibited the highest sensitivity,for which the effects of coexisting substances were investigated,and the result showed that the method had a good selectivity.This method was applied to determination of trace amounts of SA in noodle samples and kelp extract with satisfactory results.
In a Britton-Robinson buffer solution (pH 4.0~5.2),sodium alginate (SA) can be bound with some basic bisphenylnaphthylmethane dyes such as Victoria blue 4R(VB4R),Victoria blue B(VBB),or night blue (NB) to form a new product,resulting in a significant enhancement of Resonance Rayleigh Scattering (RRS) and the appearance of a new RRS spectrum.The RRS intensity was directly proportional to the SA concentration in a range of 0.075~4.0 mg/L for all the systems,which showed that the method has a fairly high sensitivity.The detection limits of SA (3σ) were 22.0×10-9 g/mL for VB4R-SA system,25.6×10-9 g/mL for VBB-SA system,and 37.5×10-9 g/mL for NB-SA system,respectively.The VB4R system exhibited the highest sensitivity,for which the effects of coexisting substances were investigated,and the result showed that the method had a good selectivity.This method was applied to determination of trace amounts of SA in noodle samples and kelp extract with satisfactory results.
2008, 25(4): 391-395
Abstract:
Polyaniline nanowires thin film electrodes were fabricated with porous anodic alumina (PAA) as template by electrochemical method.Prior to electro polymerization of aniline,the barrier layer of PAA was dissolved by electrolyzing a neutral potassium chloride solution with PAA as cathode,and a layer of nickel was deposited on PAA,which was used as catalyst.The results obtained show that the proper pH values are in a range of 2~3 for polymerization of aniline,and the critical polymerization potential of potentiostatic method is 0.1 V(vsHg/Hg2SO4).The SEM observations demonstrate that the diameter of the nanowires was about 22 nm,with an ordered distribution.Charging-discharging curves show the polyaniline nanowires thin film electrode has a higher discharge capacity than PANI thin film electrode.
Polyaniline nanowires thin film electrodes were fabricated with porous anodic alumina (PAA) as template by electrochemical method.Prior to electro polymerization of aniline,the barrier layer of PAA was dissolved by electrolyzing a neutral potassium chloride solution with PAA as cathode,and a layer of nickel was deposited on PAA,which was used as catalyst.The results obtained show that the proper pH values are in a range of 2~3 for polymerization of aniline,and the critical polymerization potential of potentiostatic method is 0.1 V(vsHg/Hg2SO4).The SEM observations demonstrate that the diameter of the nanowires was about 22 nm,with an ordered distribution.Charging-discharging curves show the polyaniline nanowires thin film electrode has a higher discharge capacity than PANI thin film electrode.
2008, 25(4): 396-400
Abstract:
Freestanding and conducting poly[poly(N-vinyl-carbazole)](PPVK) films,with a conductivity of 0.012 S/cm and electrochromic properties,were synthesized electrochemically by direct anodic oxidation of poly (N-vinyl-carbazole)(PVK).The PPVK films thus obtained showed good redox activity and high electrochemical stability in boron trifluoride diethyl etherate.FT-IR data showed that the secondary polymerization of PVK occurred at the benzene ring.The fluorescence spectra suggested that the PPVK in solid state was a good blue light emitter.On the basis of electrochemical impedance spectroscopy data,the anodic oxidation process of PPVK (0.5~1.9 V) can be divided into three segments:p-doping (0.5~1.3 V),transitional region (1.4~1.5 V),and over-oxidative region (1.6~1.9 V).
Freestanding and conducting poly[poly(N-vinyl-carbazole)](PPVK) films,with a conductivity of 0.012 S/cm and electrochromic properties,were synthesized electrochemically by direct anodic oxidation of poly (N-vinyl-carbazole)(PVK).The PPVK films thus obtained showed good redox activity and high electrochemical stability in boron trifluoride diethyl etherate.FT-IR data showed that the secondary polymerization of PVK occurred at the benzene ring.The fluorescence spectra suggested that the PPVK in solid state was a good blue light emitter.On the basis of electrochemical impedance spectroscopy data,the anodic oxidation process of PPVK (0.5~1.9 V) can be divided into three segments:p-doping (0.5~1.3 V),transitional region (1.4~1.5 V),and over-oxidative region (1.6~1.9 V).
2008, 25(4): 401-404
Abstract:
The micellization behavior of sodium dodecyl sulfate (SDS) in the presence/absence of NaCl was investigated.The correlations between the micelle aggregation number (Nm),the viscosity (η),and equili-brium concentration of SDS monomer (cUF) in the solution were studied by means of surface tension determination,steady-state fluorescence quenching,ultra-filtration,and viscosity analysis.It was found that Nm,η and cUF increased with the increase of the SDS concentration,and η increased first during the micelle formation and earlier equilibrium phases,but subsequently decreased in the transition phases when micelle shape was changing.The micelle were sphere,rod,hexagonal phase and lamellar when the SDS concentration was 15~17 times lower than that of cmc,17 times lower than that of cmc,46 times lower than that of cmc,and 60 times higher than that of cmc,respectively,in the absence of NaCl.More micelle transitions were observed in the presence of 2% NaCl,and the transition trend was the same as that in the absence of NaCl when the SDS concentration was 370 times lower than that of cmc,after which the phase separation occurred because SDS was saturated.
The micellization behavior of sodium dodecyl sulfate (SDS) in the presence/absence of NaCl was investigated.The correlations between the micelle aggregation number (Nm),the viscosity (η),and equili-brium concentration of SDS monomer (cUF) in the solution were studied by means of surface tension determination,steady-state fluorescence quenching,ultra-filtration,and viscosity analysis.It was found that Nm,η and cUF increased with the increase of the SDS concentration,and η increased first during the micelle formation and earlier equilibrium phases,but subsequently decreased in the transition phases when micelle shape was changing.The micelle were sphere,rod,hexagonal phase and lamellar when the SDS concentration was 15~17 times lower than that of cmc,17 times lower than that of cmc,46 times lower than that of cmc,and 60 times higher than that of cmc,respectively,in the absence of NaCl.More micelle transitions were observed in the presence of 2% NaCl,and the transition trend was the same as that in the absence of NaCl when the SDS concentration was 370 times lower than that of cmc,after which the phase separation occurred because SDS was saturated.
2008, 25(4): 405-408
Abstract:
We used glycin,L-tryptophan,L-glutamic acid and L-aspartic acid as substrates to react with 6-OTs-β-CD to yield amino acid modified β-cyclodextrinunder.The yields of the targeted compounds 2a~2d were 65.3%,27.9%,44.6% and 40.0%,respectively.It was determined that the optimum mass ratio between triethanolamine and water was 2:3.When the mole ratio between amino acid and cyclodextrin was 3:1,the yield was the best.The products were purified by chromatography on a Sephadex G-25 column with deionizated water as eluent,followed by recrystallization from water and ethanol.The molecular structures of the products were studied using FTIR,MS,1H NMR,13C NMR and element analysis.
We used glycin,L-tryptophan,L-glutamic acid and L-aspartic acid as substrates to react with 6-OTs-β-CD to yield amino acid modified β-cyclodextrinunder.The yields of the targeted compounds 2a~2d were 65.3%,27.9%,44.6% and 40.0%,respectively.It was determined that the optimum mass ratio between triethanolamine and water was 2:3.When the mole ratio between amino acid and cyclodextrin was 3:1,the yield was the best.The products were purified by chromatography on a Sephadex G-25 column with deionizated water as eluent,followed by recrystallization from water and ethanol.The molecular structures of the products were studied using FTIR,MS,1H NMR,13C NMR and element analysis.
2008, 25(4): 409-413
Abstract:
Horseradish peroxidase and thionine were immobilized on glassy carbon electrode surface by carrabeenan hydrogel for fabricating a peroxide biosensor.The well-defined redox peaks with the cathodic and anodic peak potentials located at about -0.264 V and -0.176 V were observed in the cyclic voltammogram for the entrapped thionone.The peak separation of 88mV and the ratio (about 1) of cathodic and anodic peak currents suggest a quasi-reversible electrochemical reaction.The mechanism of redox process coupled with proton transfer is proposed.Thionine is a good electron mediator in the reaction.Hydrogen peroxide,Cumene hydroperoxide,t-butanone peroxide and 2-butanone peroxide were reduced catalytically by horseradish peroxidase.The biosensor shows fast response,high sensitivity,good stability and reproducibility.
Horseradish peroxidase and thionine were immobilized on glassy carbon electrode surface by carrabeenan hydrogel for fabricating a peroxide biosensor.The well-defined redox peaks with the cathodic and anodic peak potentials located at about -0.264 V and -0.176 V were observed in the cyclic voltammogram for the entrapped thionone.The peak separation of 88mV and the ratio (about 1) of cathodic and anodic peak currents suggest a quasi-reversible electrochemical reaction.The mechanism of redox process coupled with proton transfer is proposed.Thionine is a good electron mediator in the reaction.Hydrogen peroxide,Cumene hydroperoxide,t-butanone peroxide and 2-butanone peroxide were reduced catalytically by horseradish peroxidase.The biosensor shows fast response,high sensitivity,good stability and reproducibility.
2008, 25(4): 414-418
Abstract:
Disperse blue 2BLN with polyamide microcapsules was prepared with p-benzoyl chloride and different diamine monomers through interfacial polymerization.The particle size and size distribution of the microcapsules were detected and analyzed by Scanning Electron Microscopy.The release of the dye from the microcapsules into an acetone solution was measured by UV-Vis.It was found that with the increase of the number of the methylene units in the diamine,both the particle size and size distribution increased,and the controlled release performance was improved.
Disperse blue 2BLN with polyamide microcapsules was prepared with p-benzoyl chloride and different diamine monomers through interfacial polymerization.The particle size and size distribution of the microcapsules were detected and analyzed by Scanning Electron Microscopy.The release of the dye from the microcapsules into an acetone solution was measured by UV-Vis.It was found that with the increase of the number of the methylene units in the diamine,both the particle size and size distribution increased,and the controlled release performance was improved.
2008, 25(4): 419-423
Abstract:
Under acidic condition,spectinomycin (SPM) was reacted with acid chrome blue K(ACBK),evans blue (EVB) or pontamine sky blue (POB) to form red or blue ion association complexes showing obvious fading peaks.The maximum fading wavelengths were at 522,608 and 626 nm,respectively,and the linear ranges were 0.2~5.0 mg/L (ACBK) and 0.1~5.4 mg/L (EVB or POB system),and their apparent molar absorptivities (ε) were 1.45×104 L/(mol·cm),1.70×104 L/(mol·cm) and 6.00×103 L/(mol·cm),respectively.Under certain concentrations,the correlation of the spectinomycin concentration with the fading degree was found to obeyed Lombard Beer's law,and a new spectrophotometric method for the determination of spectinomycin (SPM) was thus developed.The optimum reaction conditions,the precision and reliability of methed and their applications were studied.The method was used for the determination of spectinomycin in injection samples and the recoveries of them were 100%,98.8% and 99.3%,respectively.
Under acidic condition,spectinomycin (SPM) was reacted with acid chrome blue K(ACBK),evans blue (EVB) or pontamine sky blue (POB) to form red or blue ion association complexes showing obvious fading peaks.The maximum fading wavelengths were at 522,608 and 626 nm,respectively,and the linear ranges were 0.2~5.0 mg/L (ACBK) and 0.1~5.4 mg/L (EVB or POB system),and their apparent molar absorptivities (ε) were 1.45×104 L/(mol·cm),1.70×104 L/(mol·cm) and 6.00×103 L/(mol·cm),respectively.Under certain concentrations,the correlation of the spectinomycin concentration with the fading degree was found to obeyed Lombard Beer's law,and a new spectrophotometric method for the determination of spectinomycin (SPM) was thus developed.The optimum reaction conditions,the precision and reliability of methed and their applications were studied.The method was used for the determination of spectinomycin in injection samples and the recoveries of them were 100%,98.8% and 99.3%,respectively.
2008, 25(4): 424-428
Abstract:
In this paper,a novel synthesis precedure of p-tert-butoxycarbonyloxystyrene (PTBOCS) was achieved.At first phenolic hydroxyl of p-ethylphenol as original reactant was protected with tert-butoxycarbonyl (t-BOC),then was sequently α-bromizated and β-eliminated to obtain the target product.The yields of p-tert-butoxycarbonyloxybenzylethane and 1-bromo-1-(p-tert-butoxycarbonyloxybenzyl) ethane were 98% and 65%,respectively,while the yield of PTBOCS was 60%.It shows that the reaction can be carried out under a wild condition,with a high separate efficiency,and has a good potential for mass preparation of PTBOCS.The intermediate and target products were characterized by FT-IR and 1H NMR,and their structures were testified.
In this paper,a novel synthesis precedure of p-tert-butoxycarbonyloxystyrene (PTBOCS) was achieved.At first phenolic hydroxyl of p-ethylphenol as original reactant was protected with tert-butoxycarbonyl (t-BOC),then was sequently α-bromizated and β-eliminated to obtain the target product.The yields of p-tert-butoxycarbonyloxybenzylethane and 1-bromo-1-(p-tert-butoxycarbonyloxybenzyl) ethane were 98% and 65%,respectively,while the yield of PTBOCS was 60%.It shows that the reaction can be carried out under a wild condition,with a high separate efficiency,and has a good potential for mass preparation of PTBOCS.The intermediate and target products were characterized by FT-IR and 1H NMR,and their structures were testified.
2008, 25(4): 429-432
Abstract:
Metal ions copper(Ⅱ) and cobalt(Ⅱ) were successfully electrodeposited into manganese oxide by means of cyclic voltammetry,respectively.The results obtained from EDAX and SEM strongly demonstrate that the introduced metal ions were doped into manganese oxide and the configuration of manganese oxide was influenced by the doped metal ions,i.e.,the whisker of Cu2+-doped MnO2 is slender,and the particles of Co2+-doped MnO2 is smaller and denser when compared to the pure MnO2.The specific capacitance value of Cu2+-doped MnO2 is 38.52×10-3 F/cm2 and that of Co2+-doped MnO2 is 36.32×10-3 F/cm2,which are all higher than the corresponding value of pure MnO2(30.66×10-3 F/cm2),suggesting that it is feasible to employ this developed method to generate improved MnO2.
Metal ions copper(Ⅱ) and cobalt(Ⅱ) were successfully electrodeposited into manganese oxide by means of cyclic voltammetry,respectively.The results obtained from EDAX and SEM strongly demonstrate that the introduced metal ions were doped into manganese oxide and the configuration of manganese oxide was influenced by the doped metal ions,i.e.,the whisker of Cu2+-doped MnO2 is slender,and the particles of Co2+-doped MnO2 is smaller and denser when compared to the pure MnO2.The specific capacitance value of Cu2+-doped MnO2 is 38.52×10-3 F/cm2 and that of Co2+-doped MnO2 is 36.32×10-3 F/cm2,which are all higher than the corresponding value of pure MnO2(30.66×10-3 F/cm2),suggesting that it is feasible to employ this developed method to generate improved MnO2.
2008, 25(4): 433-436
Abstract:
2,6-Bis(p-methoxybenzoylactyl) pyridine was synthesized via esterification and Claisen condensation reaction with pyridine-2,6-dicarboxylic acid as starting material.The reaction conditions were investigated in detail.The product was determined by IR,1H NMR and elemental analysis.The experimental results show that the product was 2,6-bis(p-methoxybenzoylactyl) pyridine and its yield was more than 85.5% under the reaction conditions of molar ratio of dimethyl pyridine-2,6-dicarboxylate to p-methoxy acetophenone and sodium 1:2.4:2.4,prophase reaction temperature 110℃,anaphase reaction temperature 100℃ with p-methoxy acetophenone toluene solution being put drop by drop into dimethyl pyridine-2,6-dicarboxylate toluene solution.
2,6-Bis(p-methoxybenzoylactyl) pyridine was synthesized via esterification and Claisen condensation reaction with pyridine-2,6-dicarboxylic acid as starting material.The reaction conditions were investigated in detail.The product was determined by IR,1H NMR and elemental analysis.The experimental results show that the product was 2,6-bis(p-methoxybenzoylactyl) pyridine and its yield was more than 85.5% under the reaction conditions of molar ratio of dimethyl pyridine-2,6-dicarboxylate to p-methoxy acetophenone and sodium 1:2.4:2.4,prophase reaction temperature 110℃,anaphase reaction temperature 100℃ with p-methoxy acetophenone toluene solution being put drop by drop into dimethyl pyridine-2,6-dicarboxylate toluene solution.
2008, 25(4): 437-440
Abstract:
Filter fiber coated with phenyl fluorone was utilized to pre-concentrate trace amount of Germanium for determination by GFAAS.The conditions of measurement,enrichment and desorption were explored.The fibers was soaked in the pregnant solution containing trace amount of Germanium (pH=2) and stirred for 60 min at 60℃,and then the fibers were filtered and washed.A clear solution was attained after the fibers were treated with 5.0 mL of HNO3 (98%) in a microwave digester.With pyrolytic graphite tube coated with tungsten and lanthanum as a matrix modifier,Germanium in the solution was measured by GFAAS,resulting in satisfactory results.The detection limit was 0.20 μg/L,the recovery was in the range of 95.2%~104%,and the RSD was between 2.3%~11.8%.Germanium contents in zinc headings and national standard reference samples GSS-6 and GSR-5 were measured with the established method,with good agreements with the recommended values.
Filter fiber coated with phenyl fluorone was utilized to pre-concentrate trace amount of Germanium for determination by GFAAS.The conditions of measurement,enrichment and desorption were explored.The fibers was soaked in the pregnant solution containing trace amount of Germanium (pH=2) and stirred for 60 min at 60℃,and then the fibers were filtered and washed.A clear solution was attained after the fibers were treated with 5.0 mL of HNO3 (98%) in a microwave digester.With pyrolytic graphite tube coated with tungsten and lanthanum as a matrix modifier,Germanium in the solution was measured by GFAAS,resulting in satisfactory results.The detection limit was 0.20 μg/L,the recovery was in the range of 95.2%~104%,and the RSD was between 2.3%~11.8%.Germanium contents in zinc headings and national standard reference samples GSS-6 and GSR-5 were measured with the established method,with good agreements with the recommended values.
2008, 25(4): 441-444
Abstract:
Under acidic condition,the nitrogen in dioxopromethazine hydrochloride was easily protonated to form ion-complex with negative ion AuCl4-,which was extacted and carried by dichloromethane.The ion-complex entered a reversed micella of cetyltrimethylammonium chlorine containing luminol,and the dissociated AuCl4- reacted with luminol and produced an analytical chemiluminescnece signal.Under the optimum conditions,i.e.,the concentrations of hydrochloric acid,AuCl4-,luminol and sodium carbonate were 0.05 mol/L,20 mg/L,0.4×10-4 mol/L and 0.3 mol/L (pH=11.5),respectively,the R([H2O]/[CTAC]) value was 11,the flow rate (per tube) was 3.6 mL/min,the inner diameter (i.d.) of PTFE tubing was 0.8 mm,the sampling volume was 120 μL,the distance between e and injection valve was 8 cm,a glass coil (120 mm,2 mm i.d.) was used as the flow cell,the photomultiplier tube was operated at -650 V,the extraction solvent was dichloromethane,the linear range was 0.001 to 20 mg/L and the limit of detection was 0.06 μg/L with a relative standard deviation (n=11) of ca.1.4% for 1.0 mg/L dioxopromethazine hydrochloride.The method has been applied to the determination of the drug in tablets and biological fluids successfully.
Under acidic condition,the nitrogen in dioxopromethazine hydrochloride was easily protonated to form ion-complex with negative ion AuCl4-,which was extacted and carried by dichloromethane.The ion-complex entered a reversed micella of cetyltrimethylammonium chlorine containing luminol,and the dissociated AuCl4- reacted with luminol and produced an analytical chemiluminescnece signal.Under the optimum conditions,i.e.,the concentrations of hydrochloric acid,AuCl4-,luminol and sodium carbonate were 0.05 mol/L,20 mg/L,0.4×10-4 mol/L and 0.3 mol/L (pH=11.5),respectively,the R([H2O]/[CTAC]) value was 11,the flow rate (per tube) was 3.6 mL/min,the inner diameter (i.d.) of PTFE tubing was 0.8 mm,the sampling volume was 120 μL,the distance between e and injection valve was 8 cm,a glass coil (120 mm,2 mm i.d.) was used as the flow cell,the photomultiplier tube was operated at -650 V,the extraction solvent was dichloromethane,the linear range was 0.001 to 20 mg/L and the limit of detection was 0.06 μg/L with a relative standard deviation (n=11) of ca.1.4% for 1.0 mg/L dioxopromethazine hydrochloride.The method has been applied to the determination of the drug in tablets and biological fluids successfully.
2008, 25(4): 445-448
Abstract:
A novel polypyridine compound,6-(4-phenylphosphonic acid)-2,2'-bipyridine,was synthesized from 1-(4-bromophenyl) ethanone as raw material followed by four-step reactions:Mannich salt-producing reaction,Krohnke ring-coupling reaction,HIRAO aryl C-P coupling reaction of phosphonate and McKenna hydrolyzation of phosphonate.The intermediates and the target product were characterized by IR,MS and 1H NMR.The dissociation constants with pKa1 and pKa2 values of 6.2 and 2.0 measured by the potentiometric titration method are comparable to those by the absorption and emission spectra titration methods.Absorption and emission spectra of the compound show sensitivity to pH value.Electronic absorption titration studies show that the absorption bands at 322 nm,270 nm and 241 nm were blue shifted to 292 nm,262 nm and 234 nm respectively with increasing the pH value,and three isosbestic points were observed at 310 nm,280 nm and 262 nm.The corresponding emission titration studies demonstrate that the emission band at 428 nm was blue shifted to 353 nm with increasing the pH value,with an isoemissive point at 380 nm.The mechanism of sensi-tivity to pH value was also discussed.
A novel polypyridine compound,6-(4-phenylphosphonic acid)-2,2'-bipyridine,was synthesized from 1-(4-bromophenyl) ethanone as raw material followed by four-step reactions:Mannich salt-producing reaction,Krohnke ring-coupling reaction,HIRAO aryl C-P coupling reaction of phosphonate and McKenna hydrolyzation of phosphonate.The intermediates and the target product were characterized by IR,MS and 1H NMR.The dissociation constants with pKa1 and pKa2 values of 6.2 and 2.0 measured by the potentiometric titration method are comparable to those by the absorption and emission spectra titration methods.Absorption and emission spectra of the compound show sensitivity to pH value.Electronic absorption titration studies show that the absorption bands at 322 nm,270 nm and 241 nm were blue shifted to 292 nm,262 nm and 234 nm respectively with increasing the pH value,and three isosbestic points were observed at 310 nm,280 nm and 262 nm.The corresponding emission titration studies demonstrate that the emission band at 428 nm was blue shifted to 353 nm with increasing the pH value,with an isoemissive point at 380 nm.The mechanism of sensi-tivity to pH value was also discussed.
2008, 25(4): 449-454
Abstract:
Fabrication of water-soluble multi-wall carbon nanotubes (MWNTs-CR) film modified glassy carbon electrode (MWNTs-CR/GCE) was carried out via the non-covalent modification of congo red for MWNTs.The electrochemical behavior of hymecromone at MWNTs-CR/GCE was investigated by linear sweep voltammetry (LSV),successive cyclic voltammetry and chronocoulometry.Compared with that at bare GCE,the electrochemical response of hymecromone at MWNTs-CR/GCE was greatly enhanced,which was further amplified by the addition of trace cetyltrimethylammonium bromide (CTAB) in solution.In a range of 8.0×10-8~4.0×10-6 mol/L,the oxidation peak current was linear with hymecromone concentration and a low detection limit of 2.0×10-8 mol/L was obtained for 300 s accumulation at open circuit.This method was applied to determine the content of hymecromone in the compound hymecromone tablet sample,the results were satisfactory.
Fabrication of water-soluble multi-wall carbon nanotubes (MWNTs-CR) film modified glassy carbon electrode (MWNTs-CR/GCE) was carried out via the non-covalent modification of congo red for MWNTs.The electrochemical behavior of hymecromone at MWNTs-CR/GCE was investigated by linear sweep voltammetry (LSV),successive cyclic voltammetry and chronocoulometry.Compared with that at bare GCE,the electrochemical response of hymecromone at MWNTs-CR/GCE was greatly enhanced,which was further amplified by the addition of trace cetyltrimethylammonium bromide (CTAB) in solution.In a range of 8.0×10-8~4.0×10-6 mol/L,the oxidation peak current was linear with hymecromone concentration and a low detection limit of 2.0×10-8 mol/L was obtained for 300 s accumulation at open circuit.This method was applied to determine the content of hymecromone in the compound hymecromone tablet sample,the results were satisfactory.
2008, 25(4): 455-458
Abstract:
A new complex Tb(Ac)3(phen)2(HAc=acetic acid) was prepared from 2-carboxycinnamic acid,Tb(NO3)3·6H2O,and 1,10-phenanthroline (phen).The pH of the solution was adjusted to 5 with 2 mol/L NaAc solution.The title complex was characterized by IR,fluorescence spectrum,DTA-TG and X-ray single-crystal diffraction.The complex belongs to the monoclinic system with space group Cc,a=1.164 5(2) nm,b=1.792 56(3) nm,c=1.303 63(3) nm,α=90.00°,β=100.516 0(10)°,γ=90.00°,M=696.47,V=2.565 14(7) nm3,Z=4,F(000)=2 436,the final R=0.038 2 and wR=0.083 1 for 4 897[R(int)=0.029 7]independent reflections and 4 487 observed reflections (I>2σ(I)).The center Tb3+ ion is coordinated by four nitrogen atoms from the two 1,10-phenanthroline molecules and six oxygen atoms from three Ac- groups to form a mononuclear structure complex with a coordination number of 10.The carboxylic groups are bonded to the Tb3+ ion in the chelating bidentate.The coordination environment of Tb3+ ion is bicapped square-antiprism.The title complex emits intense green fluorescence under ultraviolet light excitation,its luminescence spectrum was measured at room temperature,and the emissions caused by 5D4→7Fj (j=3~6) transitions of Tb3+ ion were observed.
A new complex Tb(Ac)3(phen)2(HAc=acetic acid) was prepared from 2-carboxycinnamic acid,Tb(NO3)3·6H2O,and 1,10-phenanthroline (phen).The pH of the solution was adjusted to 5 with 2 mol/L NaAc solution.The title complex was characterized by IR,fluorescence spectrum,DTA-TG and X-ray single-crystal diffraction.The complex belongs to the monoclinic system with space group Cc,a=1.164 5(2) nm,b=1.792 56(3) nm,c=1.303 63(3) nm,α=90.00°,β=100.516 0(10)°,γ=90.00°,M=696.47,V=2.565 14(7) nm3,Z=4,F(000)=2 436,the final R=0.038 2 and wR=0.083 1 for 4 897[R(int)=0.029 7]independent reflections and 4 487 observed reflections (I>2σ(I)).The center Tb3+ ion is coordinated by four nitrogen atoms from the two 1,10-phenanthroline molecules and six oxygen atoms from three Ac- groups to form a mononuclear structure complex with a coordination number of 10.The carboxylic groups are bonded to the Tb3+ ion in the chelating bidentate.The coordination environment of Tb3+ ion is bicapped square-antiprism.The title complex emits intense green fluorescence under ultraviolet light excitation,its luminescence spectrum was measured at room temperature,and the emissions caused by 5D4→7Fj (j=3~6) transitions of Tb3+ ion were observed.
2008, 25(4): 459-463
Abstract:
Nine novel pyrazole-acyl fluoro-substituted aromatic thiourea derivatives were synthesized from phenylhydrazine and ethyl acetoacetate.The intermediate 4 was prepared via a series of reactions involving cyclization,formylation,oxidation and acylation,and was subsequently reacted with amonium thiocyanate to generate the corresponding intermediate 5 with good yield in the presence of phase transfer catalyst PEG-600.The obtained intermidiate 5 was then reacted with fluoro-substituted anilines to form the desired pyrazole-acyl fluoro-substituted aromatic thiourea derivatives,and their structures were identified by IR,1H NMR and elemental analysis.Preliminary bioassays indicated that compounds 6a,6b,6d,6e,6f,6g,6h and 6i showed inhibitory activities (100%) against Rhizoctonia sasakii,and compound 6e showed inhibitory activities (98.2%) against Gibberella zeae at a concentration of 50 mg/L.
Nine novel pyrazole-acyl fluoro-substituted aromatic thiourea derivatives were synthesized from phenylhydrazine and ethyl acetoacetate.The intermediate 4 was prepared via a series of reactions involving cyclization,formylation,oxidation and acylation,and was subsequently reacted with amonium thiocyanate to generate the corresponding intermediate 5 with good yield in the presence of phase transfer catalyst PEG-600.The obtained intermidiate 5 was then reacted with fluoro-substituted anilines to form the desired pyrazole-acyl fluoro-substituted aromatic thiourea derivatives,and their structures were identified by IR,1H NMR and elemental analysis.Preliminary bioassays indicated that compounds 6a,6b,6d,6e,6f,6g,6h and 6i showed inhibitory activities (100%) against Rhizoctonia sasakii,and compound 6e showed inhibitory activities (98.2%) against Gibberella zeae at a concentration of 50 mg/L.
2008, 25(4): 464-467
Abstract:
The water-based sol-gel method was applied to synthesize indium tin oxide (ITO) nanoparticles with m(In):m(Sn)=90:10 with polyethylene glycol (PEG) 20000 as a dispersant.The pyrolytic behavior of the dried gel and formation process of ITO were investigated by TG-DTA and XRD.The particle morphology,specific surface area and crystal size of the as-synthesized ITO powders were investigated by TEM and BET.The results indicate that monodispersed ITO nanopowers were synthesized after dried gel was calcined at 500℃.The as-synthesized sample was cubic phase In2O3 structure with a special surface area of 50 m2/g and a particle diameter of (15±5) nm,which is in good agreement with the observation of TEM,XRD and BET.The proposed technique has a significant potential for the commercial production of ITO nanopowders.
The water-based sol-gel method was applied to synthesize indium tin oxide (ITO) nanoparticles with m(In):m(Sn)=90:10 with polyethylene glycol (PEG) 20000 as a dispersant.The pyrolytic behavior of the dried gel and formation process of ITO were investigated by TG-DTA and XRD.The particle morphology,specific surface area and crystal size of the as-synthesized ITO powders were investigated by TEM and BET.The results indicate that monodispersed ITO nanopowers were synthesized after dried gel was calcined at 500℃.The as-synthesized sample was cubic phase In2O3 structure with a special surface area of 50 m2/g and a particle diameter of (15±5) nm,which is in good agreement with the observation of TEM,XRD and BET.The proposed technique has a significant potential for the commercial production of ITO nanopowders.
2008, 25(4): 468-472
Abstract:
A PBT/MgAl layered double hydroxides (MgAl-LDH) exfoliation nanocomposite was synthesized in situ from terephthalate-pillared hydroxides,Mg4Al2(OH)12[C6H4(COO)2].The samples obtained were characterized by X-ray diffraction,transmission electron microscopy,and thermal analysis.The results showed that most layers of terephthalate-pillared hydroxides were exfoliated and dispersed disorderly in the PBT matrix.DSC analysis indicated that the LDH nanolayers lowered the crystalliztion temperature and crystalli-nity,suppressed the growth of the β crystals and increased the melting point of the PBT.The thermal stability of PBT/MgAl-LDH was enhanced by the well dispersed LDH nanolayers.
A PBT/MgAl layered double hydroxides (MgAl-LDH) exfoliation nanocomposite was synthesized in situ from terephthalate-pillared hydroxides,Mg4Al2(OH)12[C6H4(COO)2].The samples obtained were characterized by X-ray diffraction,transmission electron microscopy,and thermal analysis.The results showed that most layers of terephthalate-pillared hydroxides were exfoliated and dispersed disorderly in the PBT matrix.DSC analysis indicated that the LDH nanolayers lowered the crystalliztion temperature and crystalli-nity,suppressed the growth of the β crystals and increased the melting point of the PBT.The thermal stability of PBT/MgAl-LDH was enhanced by the well dispersed LDH nanolayers.
2008, 25(4): 473-476
Abstract:
Layered nano δ-MnO2 was synthesized by reaction of KMnO4 and MnSO4 in liquid phase at different molar ratios.The materials were amorphous hydrated manganese dioxide (KxMnO2·nH2O) with small particle size and large specific surface area.Cyclic voltammetry (CV) and chronopotentiometry studies indicated that the MnO2 material obtained at a molar ratio of 4:1 exhibited excellent capacitive behavior in 0.5 mol/L Na2SO4 aqueous electrolyte between -0.2 and +1.0 V (vs.SCE),with its specific capacitance of 290.03 F/g and 195.49 F/g at a discharge current density of 94 mA/g and 1 880 mA/g.The cycling behavior was studied by chronopotentiometry technique.At a current density of 375 mA/g,the first cycle showed the highest discharge specific capacitance of 227.84 F/g,and after 100 cycles it still was 200.12 F/g,about 88% of its initial capacitance.
Layered nano δ-MnO2 was synthesized by reaction of KMnO4 and MnSO4 in liquid phase at different molar ratios.The materials were amorphous hydrated manganese dioxide (KxMnO2·nH2O) with small particle size and large specific surface area.Cyclic voltammetry (CV) and chronopotentiometry studies indicated that the MnO2 material obtained at a molar ratio of 4:1 exhibited excellent capacitive behavior in 0.5 mol/L Na2SO4 aqueous electrolyte between -0.2 and +1.0 V (vs.SCE),with its specific capacitance of 290.03 F/g and 195.49 F/g at a discharge current density of 94 mA/g and 1 880 mA/g.The cycling behavior was studied by chronopotentiometry technique.At a current density of 375 mA/g,the first cycle showed the highest discharge specific capacitance of 227.84 F/g,and after 100 cycles it still was 200.12 F/g,about 88% of its initial capacitance.
2008, 25(4): 477-480
Abstract:
2-Hydroxyethyl methacrylate (HEMA),N-vinylpyrrolidone (NVP) and N,N'Methylene bisacrylamide (MBA) were co-polymerized via inverse suspension polymerization method,and the crosslinked terpolymer microspheres with size of 100~200 μm were obtained.The effects of various factors,such as disperser kind,agitation rate,ratio of oil phase to water phase and the amount of crosslinking agent,on the formation of the microspheres and the diameter of the microspheres were examined.The chemical structure of the microspheres was characterized by FTIR,and their morphology was observed by scanning electron microscopy.
2-Hydroxyethyl methacrylate (HEMA),N-vinylpyrrolidone (NVP) and N,N'Methylene bisacrylamide (MBA) were co-polymerized via inverse suspension polymerization method,and the crosslinked terpolymer microspheres with size of 100~200 μm were obtained.The effects of various factors,such as disperser kind,agitation rate,ratio of oil phase to water phase and the amount of crosslinking agent,on the formation of the microspheres and the diameter of the microspheres were examined.The chemical structure of the microspheres was characterized by FTIR,and their morphology was observed by scanning electron microscopy.
2008, 25(4): 481-484
Abstract:
Nine α-substituted 3,5-methoxyphenylpropenoic acids (Ⅰ1~9) were synthesized from 3,5-dimethoxy-benzaldehyde and aryl acetic acids by Perkin reaction respectively.Ⅰ10 was obtained through the reduction of Ⅰ7 with iron power,and Ⅰ11 was obtained through acetylation of Ⅰ10.The structures of these novel compounds whose structures were identified by 1H NMR,IR and HR-MS.Preliminary pharmacological tests on xylene-induced mice ear swelling model demonstrated that most of the target compounds had anti-inflammatory activity,especially compounds Ⅰ6,Ⅰ9 and Ⅰ11,compared with positive control aspirin (P<0.05,P<0.01).
Nine α-substituted 3,5-methoxyphenylpropenoic acids (Ⅰ1~9) were synthesized from 3,5-dimethoxy-benzaldehyde and aryl acetic acids by Perkin reaction respectively.Ⅰ10 was obtained through the reduction of Ⅰ7 with iron power,and Ⅰ11 was obtained through acetylation of Ⅰ10.The structures of these novel compounds whose structures were identified by 1H NMR,IR and HR-MS.Preliminary pharmacological tests on xylene-induced mice ear swelling model demonstrated that most of the target compounds had anti-inflammatory activity,especially compounds Ⅰ6,Ⅰ9 and Ⅰ11,compared with positive control aspirin (P<0.05,P<0.01).
2008, 25(4): 485-488
Abstract:
BiVO4 micro-rods with brick shape were successfully synthesized in the system of polyglycol/cyclohexane/water emulsion under ultrasonic condition.The monoclinic crystal structure of the photocatalyst was determined by means of XRD,SEM and TEM,indicating that the synthesized photocatalyst was micro-rods with brick shape.Furthermore,the synthesized BiVO4 micro-rods were made of nano particles with a size of 30~50 nm.The photo absorption property showed that the band gap of the photocatalyst was ca.2.31 eV,and the BiVO4 microrods had strong photo-absorption property in both UV and visible regions.The formation mechanism of the BiVO4 micro-rods was also discussed tentatively.The photocatalytic activity of the BiVO4 micro-rods was tested in methylene blue solution under sunlight illumination.The synthesized BiVO4 micro-rods with brick shape had high photocatalytic activity because of the obviously better absorption property and the mixing valance band of O2p and Bi6s,and methylene blue was near completely decomposed within just 60 min.
BiVO4 micro-rods with brick shape were successfully synthesized in the system of polyglycol/cyclohexane/water emulsion under ultrasonic condition.The monoclinic crystal structure of the photocatalyst was determined by means of XRD,SEM and TEM,indicating that the synthesized photocatalyst was micro-rods with brick shape.Furthermore,the synthesized BiVO4 micro-rods were made of nano particles with a size of 30~50 nm.The photo absorption property showed that the band gap of the photocatalyst was ca.2.31 eV,and the BiVO4 microrods had strong photo-absorption property in both UV and visible regions.The formation mechanism of the BiVO4 micro-rods was also discussed tentatively.The photocatalytic activity of the BiVO4 micro-rods was tested in methylene blue solution under sunlight illumination.The synthesized BiVO4 micro-rods with brick shape had high photocatalytic activity because of the obviously better absorption property and the mixing valance band of O2p and Bi6s,and methylene blue was near completely decomposed within just 60 min.
2008, 25(4): 489-493
Abstract:
The optimum conditions of immobilized Lactate Oxidase with sodium alginate and ross-linked with glutaraldehyde was studied.The Lactate Oxidase was compared with its immobilized enzyme in some properties.Enzyme of 1 mL and 1 mL of 3% sodium alginate were mixed and the mixture was added dropwise into 20 mL of a 0.2 mol/L CaCl2 solution to solidify for 2 h at 25℃.Then the precipitate was cross-linked in the solution of 20 mL of 0.2% glutaraldehyde for 2 h at 37℃.After filtration and drying,the immobilized enzyme beads were obtained with a activity recovery of 39.8% for the total enzyme added.The thermal stability of the immobilized enzyme was tested.The free enzyme lost all its activity when heated at 65℃ for 1 h but the immobilized enzyme still kept 86% of the original activity.The optimal reaction temperature of the immobilized enzyme was 55℃ compared to 37℃ of free Lactate Oxidase,the optimal reaction pH of the immobilized enzyme was 7.4 as the same as that of the free enzyme.Stored at 4℃ for 50 days without any protection by reagent,the free enzyme only kept 40% of the original activity but the immobilized enzyme still retained 80% of the original activity.The calcified preparation of pyruvate from DL-Lactate by immobilized Lactate Oxidase,the yield could reach 75% after 3 h,and the immobilized enzyme maintained 85% of the activity after having been reused 5 times.
The optimum conditions of immobilized Lactate Oxidase with sodium alginate and ross-linked with glutaraldehyde was studied.The Lactate Oxidase was compared with its immobilized enzyme in some properties.Enzyme of 1 mL and 1 mL of 3% sodium alginate were mixed and the mixture was added dropwise into 20 mL of a 0.2 mol/L CaCl2 solution to solidify for 2 h at 25℃.Then the precipitate was cross-linked in the solution of 20 mL of 0.2% glutaraldehyde for 2 h at 37℃.After filtration and drying,the immobilized enzyme beads were obtained with a activity recovery of 39.8% for the total enzyme added.The thermal stability of the immobilized enzyme was tested.The free enzyme lost all its activity when heated at 65℃ for 1 h but the immobilized enzyme still kept 86% of the original activity.The optimal reaction temperature of the immobilized enzyme was 55℃ compared to 37℃ of free Lactate Oxidase,the optimal reaction pH of the immobilized enzyme was 7.4 as the same as that of the free enzyme.Stored at 4℃ for 50 days without any protection by reagent,the free enzyme only kept 40% of the original activity but the immobilized enzyme still retained 80% of the original activity.The calcified preparation of pyruvate from DL-Lactate by immobilized Lactate Oxidase,the yield could reach 75% after 3 h,and the immobilized enzyme maintained 85% of the activity after having been reused 5 times.
2008, 25(4): 494-498
Abstract:
Four novel imidazolinyl-quaternary ammonium salts were synthesized from benzoic acid,lauric acid,diethylene triamine and triethylenetetramine.The best formulation was developed by the research on the product,surfactant and inorganic anion in 5% hydrochloric acid at 50℃ with mass loss method.The inhibition effect of imidazolinyl-ammonium-salt synthesized from lauric acid and triethylenetetramine is the best when the concentration ratio of the imidazolinyl-ammonium-salt and I- is 1:1(mass ratio).Under the different time and different temperature conditions,the inhibition rate of the composite inhibitor was studied.The result shows that the inhibitive efficiency of the composite inhibitor can be increased by 1.1% compared with that of imidazoline inhibitor and the inhibitive efficiency for A3 steel can reach 99.4%.
Four novel imidazolinyl-quaternary ammonium salts were synthesized from benzoic acid,lauric acid,diethylene triamine and triethylenetetramine.The best formulation was developed by the research on the product,surfactant and inorganic anion in 5% hydrochloric acid at 50℃ with mass loss method.The inhibition effect of imidazolinyl-ammonium-salt synthesized from lauric acid and triethylenetetramine is the best when the concentration ratio of the imidazolinyl-ammonium-salt and I- is 1:1(mass ratio).Under the different time and different temperature conditions,the inhibition rate of the composite inhibitor was studied.The result shows that the inhibitive efficiency of the composite inhibitor can be increased by 1.1% compared with that of imidazoline inhibitor and the inhibitive efficiency for A3 steel can reach 99.4%.
2008, 25(4): 499-501
Abstract:
A new ceramide 1 and a known steroidal glycoside 2 were isolated from the sponge Raphiedotethya sp.collected from Sanya bay,Hainan island,China.On the basis of spectroscopic and chemical analyses,their structures were determined as (2S,3S,4R,2'R)-N-(2'-hydroxydocosanosyl)-2-amino-1,3,4-trihydroxy-henicosane (1) and 4-O-[β-D-xylopyranosyloxy]-pregn-20-en-3β,4α-diol (2).
A new ceramide 1 and a known steroidal glycoside 2 were isolated from the sponge Raphiedotethya sp.collected from Sanya bay,Hainan island,China.On the basis of spectroscopic and chemical analyses,their structures were determined as (2S,3S,4R,2'R)-N-(2'-hydroxydocosanosyl)-2-amino-1,3,4-trihydroxy-henicosane (1) and 4-O-[β-D-xylopyranosyloxy]-pregn-20-en-3β,4α-diol (2).
2008, 25(4): 502-504
Abstract:
One-step synthesis of ε-caprolactam by reaction of liquid-phase nitrosation with cyclohexane catalyzed by Mn(Ac)2 was studied by orthogonal design.The effects of reaction temperature,reaction time,amount of catalyst and the ratio of reactants on the reaction were investigated.The optimized reaction conditions were as follows:temperature 81℃,time 36 h,catalyst mass 0.5 g,ratio of nitrosyl sulfuric acid and fuming sulfuric acid mass 1:3.Under the optimized conditions,the conversion of cyclohexane reached up to 8.12% and the selectivity for ε-caprolactam was 10.54%.
One-step synthesis of ε-caprolactam by reaction of liquid-phase nitrosation with cyclohexane catalyzed by Mn(Ac)2 was studied by orthogonal design.The effects of reaction temperature,reaction time,amount of catalyst and the ratio of reactants on the reaction were investigated.The optimized reaction conditions were as follows:temperature 81℃,time 36 h,catalyst mass 0.5 g,ratio of nitrosyl sulfuric acid and fuming sulfuric acid mass 1:3.Under the optimized conditions,the conversion of cyclohexane reached up to 8.12% and the selectivity for ε-caprolactam was 10.54%.
