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2010 Volume 27 Issue 2
2010, 27(2): 125-131
doi: 10.3724/SP.J.1095.2010.90384
Abstract:
DNA origami is a new DNA self-assembly method proposed recently and is a major innovation in the field of DNA nanotechnology and self-assembly. Compared to traditional DNA self-assembly,DNA origami uses a long single-stranded genomic DNA with a series of short complementary single-strands DNA,and it can construct more complex and more controllable nanopatterns or structures and possess a wide range of potential application in the emerging field of nanotechnology. The authors briefly introduced the principles of DNA origami,then reviewed the origin and development of DNA origami and its potential application in the field of DNA chip,nanocomponents and nanomaterials. In the end we discussed the future directions of such technology.
DNA origami is a new DNA self-assembly method proposed recently and is a major innovation in the field of DNA nanotechnology and self-assembly. Compared to traditional DNA self-assembly,DNA origami uses a long single-stranded genomic DNA with a series of short complementary single-strands DNA,and it can construct more complex and more controllable nanopatterns or structures and possess a wide range of potential application in the emerging field of nanotechnology. The authors briefly introduced the principles of DNA origami,then reviewed the origin and development of DNA origami and its potential application in the field of DNA chip,nanocomponents and nanomaterials. In the end we discussed the future directions of such technology.
2010, 27(2): 132-136
doi: 10.3724/SP.J.1095.2010.90114
Abstract:
Domoic acid(DA) was used as the target compound,its structural analog 1,3,5-pentanetri-carboxylic acid was used as template molecules,4-vinyl pyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linking agent for the preparation of the molecularly imprinted polymers(MIPs). After Soxhlet extraction of the template 1,3,5-pentanetricarboxylic acid,binding sites were formed in the polymer with complementary size,shape,and positioning of chemical functionalities to 1,3,5-pentanetricarboxylic acid and also structural analog domoic acid. The molecularly imprinted polymer was investigated with the aid of equilibrium binding experiments to evaluate the molecular recognition and binding characteristics of the imprinted polymer. The results show that compared with non-imprinted polymer,the imprinted polymer exhibits a much higher affinity for domoic acid. The molecularly imprinted solid-phase extraction(MISPE) columns were prepared from a 1.0 mL glass syringe packed with 150 mg of the molecularly polymer. The MISPE procedure performed in an off-line mode coupled with reversed-phase high performance liquid chromatography was developed to extract domoic acid from Mytilus edulis and seawater samples. The mean recoveries of domoic acid from Mytilus edulis and artificial seawater spiked with 2 mg/L domoic acid were (93.4±4.9)% and (89.7±3.2)%(n=3),respectively.
Domoic acid(DA) was used as the target compound,its structural analog 1,3,5-pentanetri-carboxylic acid was used as template molecules,4-vinyl pyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linking agent for the preparation of the molecularly imprinted polymers(MIPs). After Soxhlet extraction of the template 1,3,5-pentanetricarboxylic acid,binding sites were formed in the polymer with complementary size,shape,and positioning of chemical functionalities to 1,3,5-pentanetricarboxylic acid and also structural analog domoic acid. The molecularly imprinted polymer was investigated with the aid of equilibrium binding experiments to evaluate the molecular recognition and binding characteristics of the imprinted polymer. The results show that compared with non-imprinted polymer,the imprinted polymer exhibits a much higher affinity for domoic acid. The molecularly imprinted solid-phase extraction(MISPE) columns were prepared from a 1.0 mL glass syringe packed with 150 mg of the molecularly polymer. The MISPE procedure performed in an off-line mode coupled with reversed-phase high performance liquid chromatography was developed to extract domoic acid from Mytilus edulis and seawater samples. The mean recoveries of domoic acid from Mytilus edulis and artificial seawater spiked with 2 mg/L domoic acid were (93.4±4.9)% and (89.7±3.2)%(n=3),respectively.
2010, 27(2): 137-141
doi: 10.3724/SP.J.1095.2010.90044
Abstract:
The catalytic combustion of (φ=3.6%) benzene during 200~500℃ was investigated on the supported Cu-Mn-O/Ce/Al2O3-TiO2 catalysts prepared via different wet impregnation methods and characterized by X-ray diffraction(XRD),N2 adsorption at liquid-nitrogen temperature(BET),H2 temperature programmed reduction(H2-TPR) and X-ray photoelectron spectroscopy(XPS) techniques. The results show that the 15% CuMn20x/Al2O3-TiO2 catalyst(ω(CuMn20x)=15%) achieving 79% conversion of benzene at 300℃ presented higher activity than Cu/Al2O3-TiO2 and Mn/Al2O3-TiO2 catalysts. While,the 15% CuMn20x -15% CeO2/Al2O3-TiO2 catalyst obtained by co-impregnation method attaining 81% conversion of benzene at 300℃ showed much higher catalytic activity than the catalyst prepared by two step impregnation. The addition of CeO2 in co-impregnation method can enhance the dispersion and interaction of components.
The catalytic combustion of (φ=3.6%) benzene during 200~500℃ was investigated on the supported Cu-Mn-O/Ce/Al2O3-TiO2 catalysts prepared via different wet impregnation methods and characterized by X-ray diffraction(XRD),N2 adsorption at liquid-nitrogen temperature(BET),H2 temperature programmed reduction(H2-TPR) and X-ray photoelectron spectroscopy(XPS) techniques. The results show that the 15% CuMn20x/Al2O3-TiO2 catalyst(ω(CuMn20x)=15%) achieving 79% conversion of benzene at 300℃ presented higher activity than Cu/Al2O3-TiO2 and Mn/Al2O3-TiO2 catalysts. While,the 15% CuMn20x -15% CeO2/Al2O3-TiO2 catalyst obtained by co-impregnation method attaining 81% conversion of benzene at 300℃ showed much higher catalytic activity than the catalyst prepared by two step impregnation. The addition of CeO2 in co-impregnation method can enhance the dispersion and interaction of components.
2010, 27(2): 142-146
doi: 10.3724/SP.J.1095.2010.90101
Abstract:
Well crystalled MgAl-layered double hydroxide(MgAl-LDH) and EDTA-LDH nanohybrids were synthesized via a co-precipitation method and characterized. The ligand EDTA is probably accommodated in vertical position in the interlayer space of LDH. The sorption behavior of MgAl-LDH and EDTA-LDH nanohybrids for lead ions was also investigated as a function of concentration,pH and time. It is found that both of them show good sorption ability for Pb2+. The sorption rate and the equilibrium sorption amount of Pb2+ are higher on EDTA-LDH nanohybrids than on MgAl-LDH under identical conditions,which indicate the intercalation of EDTA exhibits synergy. The sorption can be described by the pseudo-second order kinetics. The sorption occurrs in two steps,an adsorption process followed by surface precipitation. The adsorption isotherms are well fitted to Freundlich isotherm. Within the experimental concentration range,the variation of adsorbed amount is not obvious with the variation of pH because of the compound having a property of buffering pH(buffering pH effect).
Well crystalled MgAl-layered double hydroxide(MgAl-LDH) and EDTA-LDH nanohybrids were synthesized via a co-precipitation method and characterized. The ligand EDTA is probably accommodated in vertical position in the interlayer space of LDH. The sorption behavior of MgAl-LDH and EDTA-LDH nanohybrids for lead ions was also investigated as a function of concentration,pH and time. It is found that both of them show good sorption ability for Pb2+. The sorption rate and the equilibrium sorption amount of Pb2+ are higher on EDTA-LDH nanohybrids than on MgAl-LDH under identical conditions,which indicate the intercalation of EDTA exhibits synergy. The sorption can be described by the pseudo-second order kinetics. The sorption occurrs in two steps,an adsorption process followed by surface precipitation. The adsorption isotherms are well fitted to Freundlich isotherm. Within the experimental concentration range,the variation of adsorbed amount is not obvious with the variation of pH because of the compound having a property of buffering pH(buffering pH effect).
2010, 27(2): 147-150
doi: 10.3724/SP.J.1095.2010.90156
Abstract:
The diblock copolymer of styrene and chloromethyl-4-vinyl-benzene(PS-b-PCVB) was obtained by means of reverse addition fragmentation chain transfer reaction(RAFT) living free radical polymerization. The chloromethyl groups in PS-b-PCVB were transformed into azidomethyl groups,and then into 1,2,3-triazol groups via click chemistry. The diblobk copolymer containing 1,2,3-triazol groups(PS-b-PVBTM) was thus obtained. The results from NMR spectra suggested a complete transformation from chloromethyl groups to triazol groups. PS-b-PVBTM in DMF was electro-spun at 15 kV,and nanofibers with obvious phase-separation and diameters of about 100 nm were obtained. The surface of the obtained nanofibers was smoothened after being annealed at 90℃. FTIR spectra indicate that the chemical structures of the nanofibers did not change during the thermal annealing process. XPS analysis shows that the shake-up peak of Cls decreased after annealing,which indicated charge transferring. XPS analysis also demonstrates that the low-surface-tension PS block gathered on the surface of the nanofibers after annealing.
The diblock copolymer of styrene and chloromethyl-4-vinyl-benzene(PS-b-PCVB) was obtained by means of reverse addition fragmentation chain transfer reaction(RAFT) living free radical polymerization. The chloromethyl groups in PS-b-PCVB were transformed into azidomethyl groups,and then into 1,2,3-triazol groups via click chemistry. The diblobk copolymer containing 1,2,3-triazol groups(PS-b-PVBTM) was thus obtained. The results from NMR spectra suggested a complete transformation from chloromethyl groups to triazol groups. PS-b-PVBTM in DMF was electro-spun at 15 kV,and nanofibers with obvious phase-separation and diameters of about 100 nm were obtained. The surface of the obtained nanofibers was smoothened after being annealed at 90℃. FTIR spectra indicate that the chemical structures of the nanofibers did not change during the thermal annealing process. XPS analysis shows that the shake-up peak of Cls decreased after annealing,which indicated charge transferring. XPS analysis also demonstrates that the low-surface-tension PS block gathered on the surface of the nanofibers after annealing.
2010, 27(2): 151-154
doi: 10.3724/SP.J.1095.2010.90162
Abstract:
The natural rubber latexes were blended with hydrophilic organosiloxane KGF-903 for the improvement of its performance. The effect of the content of organosiloxane on blended natural rubber latex was investigated through mechanical,antiaging,hydrophilic and morphological measurement. It indicated that the mechanical and antiaging properties were improved with the addition of organosiloxane at an optimal content of 1.5%,at which the tensile strengths of improved natural rubber before and after the aging were increased by 37% and 44%,respectively. The elongations at break were monotonously increased with the addition of organosilicone at a saturated content of 3%,at which the elongations at break were improved by 57% and 50%. The more the content of organosilicone,the smaller the contact angle of the nature rubber latex. SEM analysis indicated that the dispersive state of nature rubber latex was improved with the addition of organosilicone. The two batch formulas were adopted in the manufacture of urethral catheter with an optimal addition of 1.5% of KGF-903. The catheters were obtained with smooth surface,finer evenness,moderate hardness and favorable yield of latex sacculus. The separation forces between connector and the interface of conical drainage as well as the tensile force between gas loading filler and drainage tube were improved,which guaranteed the safety of Foley latex in clinic use.
The natural rubber latexes were blended with hydrophilic organosiloxane KGF-903 for the improvement of its performance. The effect of the content of organosiloxane on blended natural rubber latex was investigated through mechanical,antiaging,hydrophilic and morphological measurement. It indicated that the mechanical and antiaging properties were improved with the addition of organosiloxane at an optimal content of 1.5%,at which the tensile strengths of improved natural rubber before and after the aging were increased by 37% and 44%,respectively. The elongations at break were monotonously increased with the addition of organosilicone at a saturated content of 3%,at which the elongations at break were improved by 57% and 50%. The more the content of organosilicone,the smaller the contact angle of the nature rubber latex. SEM analysis indicated that the dispersive state of nature rubber latex was improved with the addition of organosilicone. The two batch formulas were adopted in the manufacture of urethral catheter with an optimal addition of 1.5% of KGF-903. The catheters were obtained with smooth surface,finer evenness,moderate hardness and favorable yield of latex sacculus. The separation forces between connector and the interface of conical drainage as well as the tensile force between gas loading filler and drainage tube were improved,which guaranteed the safety of Foley latex in clinic use.
2010, 27(2): 155-158
doi: 10.3724/SP.J.1095.2010.90115
Abstract:
Multiple aldehyde groups(MASA) was prepared using sodium metaperiodate as an oxidant to oxidize sodium alginate(SA) in the mixed solvents of water and ethyl alcohol. The oxidized sodium alginate was characterized by Fehling's reagent,electric titration of hydroxylamine hydrochloride-NaOH,Ubbelohde viscometer and the crosslink reaction with gelatin. Results show that the oxidized sodium alginate reacted with Fehling's reagent in solution to form brick-red precipitate. The oxidation degree increased with the increases of the concentration of sodium metaperiodate and reaction time. The maximum of oxidation degree reached about 80% when the molar ratio of sodium periodate to monomer unit of sodium alginate was 80% and the yield was about 58.7%. The viscosity decreased rapidly with the increases of the concentration of sodium metaperiodate and reaction time. MASA with an oxidation degree of 20%,40% or 60% gelled gelatin within 5 min at 37℃. Thereby,polysaccharide crosslinker of multi-aldehyde sodium alginate with controllable molecular mass and oxidation degree could be prepared in a high yield by adjusting the concentration of sodium metaperiodate and reaction time in a water-ethanol medium.
Multiple aldehyde groups(MASA) was prepared using sodium metaperiodate as an oxidant to oxidize sodium alginate(SA) in the mixed solvents of water and ethyl alcohol. The oxidized sodium alginate was characterized by Fehling's reagent,electric titration of hydroxylamine hydrochloride-NaOH,Ubbelohde viscometer and the crosslink reaction with gelatin. Results show that the oxidized sodium alginate reacted with Fehling's reagent in solution to form brick-red precipitate. The oxidation degree increased with the increases of the concentration of sodium metaperiodate and reaction time. The maximum of oxidation degree reached about 80% when the molar ratio of sodium periodate to monomer unit of sodium alginate was 80% and the yield was about 58.7%. The viscosity decreased rapidly with the increases of the concentration of sodium metaperiodate and reaction time. MASA with an oxidation degree of 20%,40% or 60% gelled gelatin within 5 min at 37℃. Thereby,polysaccharide crosslinker of multi-aldehyde sodium alginate with controllable molecular mass and oxidation degree could be prepared in a high yield by adjusting the concentration of sodium metaperiodate and reaction time in a water-ethanol medium.
2010, 27(2): 159-163
doi: 10.3724/SP.J.1095.2010.90140
Abstract:
An intermediate was prepared by the esterification of neopentyl glycol with paraphthaloyl chloride. The polymerization degree of the intermediate was between 3.5 and 1.45 as n(NPG)/n(TPA) was increased from 2.4 to 3.0. The yield of the intermediate was 75.5%. The complex ester was produced by esterification of the intermediate with oleic acid with a yield of 88.5%. The result shows that the viscosity was improved with the increase of the molecular mass of the product,the viscosity at 100℃ was between 17.8~27.6 mm2/s,the viscosity index was more than 125,solidifying point was below -27℃,the oxidative stability was also improved with the increase of the molecular mass of the product. The biodegradabilities of complex esters were more than 70%. The value of PB was 784 N,the value of wear diameter was 0.41 mm,the temperature of thermal decomposition was above 250℃. The complex esters can be used as excellent green lubricants.
An intermediate was prepared by the esterification of neopentyl glycol with paraphthaloyl chloride. The polymerization degree of the intermediate was between 3.5 and 1.45 as n(NPG)/n(TPA) was increased from 2.4 to 3.0. The yield of the intermediate was 75.5%. The complex ester was produced by esterification of the intermediate with oleic acid with a yield of 88.5%. The result shows that the viscosity was improved with the increase of the molecular mass of the product,the viscosity at 100℃ was between 17.8~27.6 mm2/s,the viscosity index was more than 125,solidifying point was below -27℃,the oxidative stability was also improved with the increase of the molecular mass of the product. The biodegradabilities of complex esters were more than 70%. The value of PB was 784 N,the value of wear diameter was 0.41 mm,the temperature of thermal decomposition was above 250℃. The complex esters can be used as excellent green lubricants.
2010, 27(2): 164-168
doi: 10.3724/SP.J.1095.2010.90164
Abstract:
In the search of bioactive compounds,a series of fluorine-substituted pyridine-heterocyclic carboxylate compounds were synthesized with methyl fluoroacetate,cyanacetamide,ethyl formic ester,alcoholic and phenolic compounds via ring closure,chlorination,hydrolyzation,acylchloriration and esterification reactions. The overall yield was about 38%. All compounds were characterized by 1H NMR,13C NMR,IR,MS and elemental analysis. The preliminary bioassay results show that compounds 1e,1i,1j and 1k exhibited 61.9%~100% mortality against culex mosquito at 500 mg/L and little inhibition against several tested fungi. Compound 1k had better bioactivity and exhibited 100% mortality against armyworm and culex mosquito at 500 mg/L. The preliminary structure-activity relationship results reveal that the title phenolic compounds have good bioactivities while the alcoholic compounds do not.
In the search of bioactive compounds,a series of fluorine-substituted pyridine-heterocyclic carboxylate compounds were synthesized with methyl fluoroacetate,cyanacetamide,ethyl formic ester,alcoholic and phenolic compounds via ring closure,chlorination,hydrolyzation,acylchloriration and esterification reactions. The overall yield was about 38%. All compounds were characterized by 1H NMR,13C NMR,IR,MS and elemental analysis. The preliminary bioassay results show that compounds 1e,1i,1j and 1k exhibited 61.9%~100% mortality against culex mosquito at 500 mg/L and little inhibition against several tested fungi. Compound 1k had better bioactivity and exhibited 100% mortality against armyworm and culex mosquito at 500 mg/L. The preliminary structure-activity relationship results reveal that the title phenolic compounds have good bioactivities while the alcoholic compounds do not.
2010, 27(2): 169-172
doi: 10.3724/SP.J.1095.2010.90090
Abstract:
A series of novel fluorenetriazo-salicylaldehyde thiosemicarbazone derivatives were synthesized by reaction of fluorene,salicylaldehyde with thiosemicarbazone,and their structures were confirmed by IR,1H NMR,MS and elemental analysis. The utensil rape rooting tests show that all the compounds have good accelerating effects on rape rooting at a low concentration,but have inhibitory or low accelerating effects on rape rooting at a high concentration. The effect on rape rooting is related to the property of substituent group.
A series of novel fluorenetriazo-salicylaldehyde thiosemicarbazone derivatives were synthesized by reaction of fluorene,salicylaldehyde with thiosemicarbazone,and their structures were confirmed by IR,1H NMR,MS and elemental analysis. The utensil rape rooting tests show that all the compounds have good accelerating effects on rape rooting at a low concentration,but have inhibitory or low accelerating effects on rape rooting at a high concentration. The effect on rape rooting is related to the property of substituent group.
2010, 27(2): 173-177
doi: 10.3724/SP.J.1095.2010.90077
Abstract:
A new heteropolyacid-organic charge transfer salt (C3H5N2)3[PMo12O40] was synthesized from phosphomolybdic acid and imidazole,and characterized by means of elemental analysis,infrared spectrum(IR),diffuse reflectance spectrum(DRS),electron spin resonance(ESR) and thermal analysis techniques(TG). The decomposition mechanism and nonisothermal kinetic parameters of the salt were obtained from an analysis of the TG-DTG curves obtained by means of the single scanning methods(the Achar method and Coats-Redfern method). For the first step of the thermal decomposition reaction,the possible reaction mechanism was suggested to be a three-dimensional diffusion. Its kinetic equation with parameters is dα/dt=1.58×108[1-(1-α)1/3]-1 (1-α)2/3 exp(-40 931.0/T) with E=340.30 kJ/mol and A=1.05×108 s-1. The salt shows photochromism under ultraviolet light,and its photochromic reaction was studied with solid diffuse reflectance spectra and found to exhibit first-order or pseudo-first-order kinetics with a rate constant k=9.80×10-5 s-1.
A new heteropolyacid-organic charge transfer salt (C3H5N2)3[PMo12O40] was synthesized from phosphomolybdic acid and imidazole,and characterized by means of elemental analysis,infrared spectrum(IR),diffuse reflectance spectrum(DRS),electron spin resonance(ESR) and thermal analysis techniques(TG). The decomposition mechanism and nonisothermal kinetic parameters of the salt were obtained from an analysis of the TG-DTG curves obtained by means of the single scanning methods(the Achar method and Coats-Redfern method). For the first step of the thermal decomposition reaction,the possible reaction mechanism was suggested to be a three-dimensional diffusion. Its kinetic equation with parameters is dα/dt=1.58×108[1-(1-α)1/3]-1 (1-α)2/3 exp(-40 931.0/T) with E=340.30 kJ/mol and A=1.05×108 s-1. The salt shows photochromism under ultraviolet light,and its photochromic reaction was studied with solid diffuse reflectance spectra and found to exhibit first-order or pseudo-first-order kinetics with a rate constant k=9.80×10-5 s-1.
2010, 27(2): 178-182
doi: 10.3724/SP.J.1095.2010.90098
Abstract:
A complex composed of ofloxacin(OFLX) and silicotungstic heteropolyacid(SiW) was studied by means of fluorescence and IR spectroscopies. SiW can quench the fluorescence of OFLX by forming a new complex. The binding site number n,apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The result indicates that the electrostatic and hydrophobic interactions play a major role in stabilizing the complex. The IR spectrum confirms the presence of Keggin type anion in the SiW-OFLX complex.
A complex composed of ofloxacin(OFLX) and silicotungstic heteropolyacid(SiW) was studied by means of fluorescence and IR spectroscopies. SiW can quench the fluorescence of OFLX by forming a new complex. The binding site number n,apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The result indicates that the electrostatic and hydrophobic interactions play a major role in stabilizing the complex. The IR spectrum confirms the presence of Keggin type anion in the SiW-OFLX complex.
2010, 27(2): 183-190
doi: 10.3724/SP.J.1095.2010.90147
Abstract:
A composite electrocatalyst cobalt-phthalocyanine loaded on carbon black VulcanXC-72(CoPc/C) was synthesized in one-step reaction through calcination,which could be used as the catalyst of air electrode. The product was characterized by XRD and IR techniques and shown to be CoPc/C composite with an average particle size of 30 nm. Its activity for oxygen reduction reaction(ORR) was evaluated by polarization curve and impedance spectrum in 6 mol/L KOH solution. With VulcanXC-72 pretreated in HNO3 as the carbon support,the CoPc/C calcinated at 600℃ exhibited the best catalytic activity. The polarization plots recorded at the electrode catalyzed with this product displyed an onset for ORR at -0.03 V(Hg/HgO). The current density is 90×10-3 A/cm2 at -0.2 V in air.
A composite electrocatalyst cobalt-phthalocyanine loaded on carbon black VulcanXC-72(CoPc/C) was synthesized in one-step reaction through calcination,which could be used as the catalyst of air electrode. The product was characterized by XRD and IR techniques and shown to be CoPc/C composite with an average particle size of 30 nm. Its activity for oxygen reduction reaction(ORR) was evaluated by polarization curve and impedance spectrum in 6 mol/L KOH solution. With VulcanXC-72 pretreated in HNO3 as the carbon support,the CoPc/C calcinated at 600℃ exhibited the best catalytic activity. The polarization plots recorded at the electrode catalyzed with this product displyed an onset for ORR at -0.03 V(Hg/HgO). The current density is 90×10-3 A/cm2 at -0.2 V in air.
2010, 27(2): 191-196
doi: 10.3724/SP.J.1095.2010.90268
Abstract:
The interaction between chromium(Ⅵ) and bovine serum albumin(BSA) was investigated via fluorescence,UV/Vis and CD spectroscopies. It is shown that Cr(Ⅵ) decreased the intensity of UV absorption peak of BSA,accompanied by red-shift. The fluorescence experimental results show that the fluorescence quenching of BSA by chromium(Ⅵ) is a result of the formation of Cr(Ⅵ)-BSA complex; static quenching was confirmed to result in the fluorescence quenching. The thermodynamic parameters were calculated(△Gθ<0,△Hθ=-12.60 kJ/mol,△Sθ=56.60 J/(mol·k)),the process of binding Cr(Ⅵ) molecule on BSA was a spontaneous molecular interaction procedure,during which the entropy increased and the Gibbs free energy decreased. The electrostatic force interaction plays a major role in stabilizing the complex. The distance between the tryptophane residue of BSA and Cr2O72- anion(2.85 nm) was determined by the mechanism of the energy transfer of dipole-dipole interaction. The results of synchronous fluorescence spectroscopy and CD spectroscopy indicate that Cr(Ⅵ) had a strong impact on BSA conformation,resulting in the change of the tryptophane residues environments and the decrease of the α-helical content of the protein.
The interaction between chromium(Ⅵ) and bovine serum albumin(BSA) was investigated via fluorescence,UV/Vis and CD spectroscopies. It is shown that Cr(Ⅵ) decreased the intensity of UV absorption peak of BSA,accompanied by red-shift. The fluorescence experimental results show that the fluorescence quenching of BSA by chromium(Ⅵ) is a result of the formation of Cr(Ⅵ)-BSA complex; static quenching was confirmed to result in the fluorescence quenching. The thermodynamic parameters were calculated(△Gθ<0,△Hθ=-12.60 kJ/mol,△Sθ=56.60 J/(mol·k)),the process of binding Cr(Ⅵ) molecule on BSA was a spontaneous molecular interaction procedure,during which the entropy increased and the Gibbs free energy decreased. The electrostatic force interaction plays a major role in stabilizing the complex. The distance between the tryptophane residue of BSA and Cr2O72- anion(2.85 nm) was determined by the mechanism of the energy transfer of dipole-dipole interaction. The results of synchronous fluorescence spectroscopy and CD spectroscopy indicate that Cr(Ⅵ) had a strong impact on BSA conformation,resulting in the change of the tryptophane residues environments and the decrease of the α-helical content of the protein.
2010, 27(2): 197-200
doi: 10.3724/SP.J.1095.2010.90173
Abstract:
Multi-welled carbon nanotube supported iron oxide(Fe2O3/CNT) as catalyst for the oxidation of phenol in waste water by hydrogen peroxide was studied. The catalysts samples was synthesized by a chemical precipitation in the presence or absence of polyvinyl alcohol(PVA) and followed by a heat treatment. X-ray diffraction(XRD) result revealed two crystalline (α-type and γ-type) iron oxide were presented in the catalyst. The content of the active metal oxide component on the CNT was about 15.1%. The catalytic performance were carried out in a glass vessel in a batch operation mode at atmospheric pressure and temperature ranging from 50℃ to 90℃. At a temperature of 80℃,initial phenol concentration of 350 mg/L,hydrogen peroxide 1500 mg/L and catalysts 1.0 g/L,the phenol conversion and the COD removal rate of the water were 100% and 86.1%,respectively,after 240 min oxidation. The influence of using PVA in the process of catalysts preparation on their catalytic performance was discussed.
Multi-welled carbon nanotube supported iron oxide(Fe2O3/CNT) as catalyst for the oxidation of phenol in waste water by hydrogen peroxide was studied. The catalysts samples was synthesized by a chemical precipitation in the presence or absence of polyvinyl alcohol(PVA) and followed by a heat treatment. X-ray diffraction(XRD) result revealed two crystalline (α-type and γ-type) iron oxide were presented in the catalyst. The content of the active metal oxide component on the CNT was about 15.1%. The catalytic performance were carried out in a glass vessel in a batch operation mode at atmospheric pressure and temperature ranging from 50℃ to 90℃. At a temperature of 80℃,initial phenol concentration of 350 mg/L,hydrogen peroxide 1500 mg/L and catalysts 1.0 g/L,the phenol conversion and the COD removal rate of the water were 100% and 86.1%,respectively,after 240 min oxidation. The influence of using PVA in the process of catalysts preparation on their catalytic performance was discussed.
2010, 27(2): 201-205
doi: 10.3724/SP.J.1095.2010.90119
Abstract:
The fluorescence properties and mechanism of La(Ⅲ),9-3,5-dibromosalicyl fluorone(DBSAF) and sodium dodeceyl sulfate(SDS) fluorescent complex system were investigated. A method was developed for the determination of trace La(Ⅲ) based on the fluorometric quenching effect of DBSAF-SDS.The results indicate that in the buffer solution of (CH2)6N4-HCl at pH=5.4,the La(Ⅲ)-DBSAF-SDS fluorescent complex has maximum excitation at 520 nm,and maximum emission at 560 nm. The fluorescence intensity is proportional to the amount of La(Ⅲ) in a range of 1.6~800 μg/L. The detection limit of La(Ⅲ) is 0.12 μg/L. This method is applicable to the determination of trace La in copper alloy with satisfactory results.
The fluorescence properties and mechanism of La(Ⅲ),9-3,5-dibromosalicyl fluorone(DBSAF) and sodium dodeceyl sulfate(SDS) fluorescent complex system were investigated. A method was developed for the determination of trace La(Ⅲ) based on the fluorometric quenching effect of DBSAF-SDS.The results indicate that in the buffer solution of (CH2)6N4-HCl at pH=5.4,the La(Ⅲ)-DBSAF-SDS fluorescent complex has maximum excitation at 520 nm,and maximum emission at 560 nm. The fluorescence intensity is proportional to the amount of La(Ⅲ) in a range of 1.6~800 μg/L. The detection limit of La(Ⅲ) is 0.12 μg/L. This method is applicable to the determination of trace La in copper alloy with satisfactory results.
2010, 27(2): 206-210
doi: 10.3724/SP.J.1095.2010.90127
Abstract:
In a pH 4.2~4.4 acidic medium,palladium(Ⅱ) reacted with moroxydine hydrochloride to form a cationic chelate[Pd(ABOB)2]2+,which reacted further with eosin Y(EY),erythrosin(Ery) or dibromofluorescein(DBF) to form ion-association complexes,respectively. As a result,the resonance rayleigh scattering(RRS) intensities were enhanced greatly. The maximum RRS peak of three systems were located at 315 nm,RRS intensity was proportional to the concentration of moroxydine hydrochloride (ABOB) in a range of 0.012×10-6~1.2×10-6 g/mL (EY),0.23×10-6~2.3×10-6 g/mL (Ery) or 0.24×10-6~1.5×10-6 g/mL (DBF),and the detection limit(3σ) was 0.0036×10-6 g/mL (EY),0.070×10-6 g/mL(Ery) or 0.025×10-6 g/mL (DBF),separately. The optimal conditions of the reaction and the properties of analytical chemistry were investigated. Therefore,a new method for the determination of ABOB by RRS was developed. The method has a high sensitivity and good selectivity,which has been applied to the determination of ABOB in serum and urine samples with satisfactory results. In addtion,the formation of the ion-associaiation complexes,the reaction mechanism and the reasons of scattering enhanced has been discussed.
In a pH 4.2~4.4 acidic medium,palladium(Ⅱ) reacted with moroxydine hydrochloride to form a cationic chelate[Pd(ABOB)2]2+,which reacted further with eosin Y(EY),erythrosin(Ery) or dibromofluorescein(DBF) to form ion-association complexes,respectively. As a result,the resonance rayleigh scattering(RRS) intensities were enhanced greatly. The maximum RRS peak of three systems were located at 315 nm,RRS intensity was proportional to the concentration of moroxydine hydrochloride (ABOB) in a range of 0.012×10-6~1.2×10-6 g/mL (EY),0.23×10-6~2.3×10-6 g/mL (Ery) or 0.24×10-6~1.5×10-6 g/mL (DBF),and the detection limit(3σ) was 0.0036×10-6 g/mL (EY),0.070×10-6 g/mL(Ery) or 0.025×10-6 g/mL (DBF),separately. The optimal conditions of the reaction and the properties of analytical chemistry were investigated. Therefore,a new method for the determination of ABOB by RRS was developed. The method has a high sensitivity and good selectivity,which has been applied to the determination of ABOB in serum and urine samples with satisfactory results. In addtion,the formation of the ion-associaiation complexes,the reaction mechanism and the reasons of scattering enhanced has been discussed.
2010, 27(2): 211-214
doi: 10.3724/SP.J.1095.2010.90068
Abstract:
Coke-based carbon absorption material was prepared by nitric acid pre-oxidation of coke powder followed by zinc chloride chemical activation. The absorption characteristics were studied for the coke-based carbon absorbing copper ions in water. The results show that the absorption equilibrium time was 90 min,and the absorption accorded with the Langmuir model. In addition,the results of △Hθ>0,△Gθ<0 at different temperatures reveal that the adsorption was a spontaneous endothermic process,and that △Sθ>0 indicates that the order reduced and the chaos increased for the copper ion adsorption the solid-liquid interface. Finally,the experimental data were fitted to second order kinetics model and the correlation coefficient(R2) was 0.9991,suggesting that the adsorption followed second order kinetics.
Coke-based carbon absorption material was prepared by nitric acid pre-oxidation of coke powder followed by zinc chloride chemical activation. The absorption characteristics were studied for the coke-based carbon absorbing copper ions in water. The results show that the absorption equilibrium time was 90 min,and the absorption accorded with the Langmuir model. In addition,the results of △Hθ>0,△Gθ<0 at different temperatures reveal that the adsorption was a spontaneous endothermic process,and that △Sθ>0 indicates that the order reduced and the chaos increased for the copper ion adsorption the solid-liquid interface. Finally,the experimental data were fitted to second order kinetics model and the correlation coefficient(R2) was 0.9991,suggesting that the adsorption followed second order kinetics.
2010, 27(2): 215-219
doi: 10.3724/SP.J.1095.2010.90104
Abstract:
Precious metal catalytic electrodes were prepared by thermal decomposition. The surface and the composition of the electrodes were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD) and energy dispersive X-ray spectroscopy(EDS). The electro-catalytic activity of the electrodes was tested for the electrolysis of coal slurry using the two-electrode system. The results show that in the catalytic coating,Pt exists in the form of Pt,but Ru,Ir exist in the form of oxides. After electrolysis with the electrodes for 10 h,the current and gas production rate were relatively stable,and in the whole process of electrolysis,hydrogen electrolysis efficiency was close to 100%,the anode electrolysis efficiency to 40%. Compared with that of the Ti/Pt electrode,the catalytic activity of the electrodes,especially the dual-dimensional Ti/Pt-RuO2(1:1) and Ti/Pt-IrO2(1:1) has been greatly improved.
Precious metal catalytic electrodes were prepared by thermal decomposition. The surface and the composition of the electrodes were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD) and energy dispersive X-ray spectroscopy(EDS). The electro-catalytic activity of the electrodes was tested for the electrolysis of coal slurry using the two-electrode system. The results show that in the catalytic coating,Pt exists in the form of Pt,but Ru,Ir exist in the form of oxides. After electrolysis with the electrodes for 10 h,the current and gas production rate were relatively stable,and in the whole process of electrolysis,hydrogen electrolysis efficiency was close to 100%,the anode electrolysis efficiency to 40%. Compared with that of the Ti/Pt electrode,the catalytic activity of the electrodes,especially the dual-dimensional Ti/Pt-RuO2(1:1) and Ti/Pt-IrO2(1:1) has been greatly improved.
2010, 27(2): 220-226
doi: 10.3724/SP.J.1095.2010.90106
Abstract:
A series of yttrium(Ⅲ) ion doped layered lithium manganese oxides LiYxMn1-xO2(x:0.01,0.02,0.03 and 0.05) compounds was synthesized with Na2CO3,(CH3COO)2 Mn·4H2O, CH3COOLi·2H2O and Y2O3 as the starting materials by means of two-step high temperautre solid state reaction and hydrothermal ion exchange method. The Y3+-doping effect on the structure and the electrochemical performances of the samples were investigated by XRD,XPS,cyclic voltammetry and charge-discharge tests. The XRD results show that the samples exhibit the same phase as pure monoclinic layered sturcture. Electrochemical performances indicate that the yttrium ions can partially replace Mn3+ in monoclinic structure LiMnO2 materials. Because the radius of Y3+ is bigger than that of Mn3+,samples doped with yittrium elements have larger lattice constant compared with that of undoped sample. Doping enables lithium ions to transport more freely in the three dimensional pathway,and all yittrium element doped materials show good cycle stability. Experiments of doping ratio and electrochemistry performance were carried out. The compound LiY0.021Mn0.979O2 obtained exhibited a better performance whose initial discharge specific capacity reached 123.4 mA·h/g respectively. After 100 cycles,the discharge capacity maintained 212.1 mA·h/g,which is much higher than the discharge capacity 138 mA·h/g of the undoped monoclinic structure LiMnO2 materials. AC analysis shows lower electrochemical impedance and the diffusibility of lithium ions is clearly improved due to Y3+ doping.
A series of yttrium(Ⅲ) ion doped layered lithium manganese oxides LiYxMn1-xO2(x:0.01,0.02,0.03 and 0.05) compounds was synthesized with Na2CO3,(CH3COO)2 Mn·4H2O, CH3COOLi·2H2O and Y2O3 as the starting materials by means of two-step high temperautre solid state reaction and hydrothermal ion exchange method. The Y3+-doping effect on the structure and the electrochemical performances of the samples were investigated by XRD,XPS,cyclic voltammetry and charge-discharge tests. The XRD results show that the samples exhibit the same phase as pure monoclinic layered sturcture. Electrochemical performances indicate that the yttrium ions can partially replace Mn3+ in monoclinic structure LiMnO2 materials. Because the radius of Y3+ is bigger than that of Mn3+,samples doped with yittrium elements have larger lattice constant compared with that of undoped sample. Doping enables lithium ions to transport more freely in the three dimensional pathway,and all yittrium element doped materials show good cycle stability. Experiments of doping ratio and electrochemistry performance were carried out. The compound LiY0.021Mn0.979O2 obtained exhibited a better performance whose initial discharge specific capacity reached 123.4 mA·h/g respectively. After 100 cycles,the discharge capacity maintained 212.1 mA·h/g,which is much higher than the discharge capacity 138 mA·h/g of the undoped monoclinic structure LiMnO2 materials. AC analysis shows lower electrochemical impedance and the diffusibility of lithium ions is clearly improved due to Y3+ doping.
2010, 27(2): 227-230
doi: 10.3724/SP.J.1095.2010.90142
Abstract:
The influences of Fe2+/H2O2 on the ζ potential and stability of colloidal urea-formaldehyde(UF) resins were studied by means of a colloidal chemistry method. The results show that the average ζ potential of urea-formaldehyde colloidal particles is about -32.5 mV at a pH value of 8.0 and they exist in monodisperse state. The ζ potential is decreased rapidly with the addition of ferrous ions or hydrogen peroxide,which causes a decrease of expulsion potential,the aggregation of colloidal particles,an increase of viscosity and eventually the formation of stable UF resin gels. However,the influences of hydrogen peroxide on ζ potential and the viscosity η of UF colloidal particles are much less than those of the ferrous ions. pH value plays an important role in keeping the stability of the colloidal particles. The system has the highest ζ potential at pH≈9. When pH >9,the absolute value of ζ potential decreases more significantly. The mechanism of Fe2+/H2O2 affecting the stability of UF adhesive was discussed based on colloidal electric double layers theory.
The influences of Fe2+/H2O2 on the ζ potential and stability of colloidal urea-formaldehyde(UF) resins were studied by means of a colloidal chemistry method. The results show that the average ζ potential of urea-formaldehyde colloidal particles is about -32.5 mV at a pH value of 8.0 and they exist in monodisperse state. The ζ potential is decreased rapidly with the addition of ferrous ions or hydrogen peroxide,which causes a decrease of expulsion potential,the aggregation of colloidal particles,an increase of viscosity and eventually the formation of stable UF resin gels. However,the influences of hydrogen peroxide on ζ potential and the viscosity η of UF colloidal particles are much less than those of the ferrous ions. pH value plays an important role in keeping the stability of the colloidal particles. The system has the highest ζ potential at pH≈9. When pH >9,the absolute value of ζ potential decreases more significantly. The mechanism of Fe2+/H2O2 affecting the stability of UF adhesive was discussed based on colloidal electric double layers theory.
2010, 27(2): 231-236
doi: 10.3724/SP.J.1095.2010.90159
Abstract:
Anthocyanin stability of tree penoy was evaluated under different pH and temperature conditions during heating. Analysis of kinetic data suggests a first-order reaction for the degradation of tree penoy anthocyanin with the half-lives of 27.0 to 7.9,32.1 to 8.5,27.9 to 8.9,35.9 to 9.4 and 27.3 to 10.7 h for samples at pH 2.6,3.0,3.6,4.0 and 4.6 between 70 and 90℃,respectively. Increasing temperature from 70 to 90℃,it enhanced the degradation of anthocyanin during heating. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. The activation energy values for the degradation of tree penoy anthocyanin at different pH values(2.6~4.6) ranged from 48.4 to 69.4 kJ/mol. The first order kinetic constants show the following decreased order for individual anthocyanins:cyanidin 3-O-glucoside > peonidin 3-O-glucoside > cyanidin 3,5-di-O-glucoside > peonidin 3,5-di-O-glucoside. Tree penoy anthocyanin degradation involves in brown pigment formation. The browning index increased with increasing heating time,temperature and pH.
Anthocyanin stability of tree penoy was evaluated under different pH and temperature conditions during heating. Analysis of kinetic data suggests a first-order reaction for the degradation of tree penoy anthocyanin with the half-lives of 27.0 to 7.9,32.1 to 8.5,27.9 to 8.9,35.9 to 9.4 and 27.3 to 10.7 h for samples at pH 2.6,3.0,3.6,4.0 and 4.6 between 70 and 90℃,respectively. Increasing temperature from 70 to 90℃,it enhanced the degradation of anthocyanin during heating. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. The activation energy values for the degradation of tree penoy anthocyanin at different pH values(2.6~4.6) ranged from 48.4 to 69.4 kJ/mol. The first order kinetic constants show the following decreased order for individual anthocyanins:cyanidin 3-O-glucoside > peonidin 3-O-glucoside > cyanidin 3,5-di-O-glucoside > peonidin 3,5-di-O-glucoside. Tree penoy anthocyanin degradation involves in brown pigment formation. The browning index increased with increasing heating time,temperature and pH.
2010, 27(2): 237-239
doi: 10.3724/SP.J.1095.2010.90188
Abstract:
A novel solid sulfonic acid was prepared from coconut shell via carbonization and sulfonation and used as a catalyst for the condensation of aldehydes and resorcinol,and calix[4] resorcinarenes were prepared rapidly in good yield(49%~95%). The structures of the target compounds were confirmed by IR,1H NMR and MS.
A novel solid sulfonic acid was prepared from coconut shell via carbonization and sulfonation and used as a catalyst for the condensation of aldehydes and resorcinol,and calix[4] resorcinarenes were prepared rapidly in good yield(49%~95%). The structures of the target compounds were confirmed by IR,1H NMR and MS.
2010, 27(2): 240-242
doi: 10.3724/SP.J.1095.2010.90175
Abstract:
(R)-4-Benzyl-2-oxazolidinone,an Evans chiral auxiliary reagent,was synthesized from D-phenylalanine as a starting material,which was reduced by sodium borohydride/iodine followed by reacting with bis(trichloromethyl) carbonate under alkaline condition. Then the (R)-4-benzyl-2-oxazolidinone was condensated with propionyl chloride and coupled with lithium diisopropylamide(LDA). After the anti-Aldol reaction,a unique segment of Stereocalpin A was obtained in an overall yield of 30.6% which has moderate cytotoxicity against three human solid tumor cell lines(HT-29,B16/F10,HepG2). The developed method is efficient to synthesize this compound with high yield and selectivity.
(R)-4-Benzyl-2-oxazolidinone,an Evans chiral auxiliary reagent,was synthesized from D-phenylalanine as a starting material,which was reduced by sodium borohydride/iodine followed by reacting with bis(trichloromethyl) carbonate under alkaline condition. Then the (R)-4-benzyl-2-oxazolidinone was condensated with propionyl chloride and coupled with lithium diisopropylamide(LDA). After the anti-Aldol reaction,a unique segment of Stereocalpin A was obtained in an overall yield of 30.6% which has moderate cytotoxicity against three human solid tumor cell lines(HT-29,B16/F10,HepG2). The developed method is efficient to synthesize this compound with high yield and selectivity.
2010, 27(2): 243-245
doi: 10.3724/SP.J.1095.2010.90039
Abstract:
The chitosan-vitamin C complex was synthesized through the electrostatic attractions among ions. The structure of complex was characterized by FT-IR and DSC. The results of solubility testing show the complex was water soluble. The testing results of auto-oxidation rates of pyrogallic acid indicate the complex was superior to chitosan in scavenging·O2-.
The chitosan-vitamin C complex was synthesized through the electrostatic attractions among ions. The structure of complex was characterized by FT-IR and DSC. The results of solubility testing show the complex was water soluble. The testing results of auto-oxidation rates of pyrogallic acid indicate the complex was superior to chitosan in scavenging·O2-.
2010, 27(2): 246-248
doi: 10.3724/SP.J.1095.2010.90063
Abstract:
1-Dimethyl-3-phenylpropylamine enantiomer was separated with hydroxypropyl-β-cyclodextrin(HP-β-CD) as chiral selector by means of pressurized capillary electrochromatography(pCEC). The optimal experimental conditions are HP-β-CD concentration 10 g/L,background buffer pH=7.6,capillary temperature 16℃,voltage 10 kV,and the mobile phase consisted of a solution of acetonitrile and phosphate at a volume ratio of V(CH3CN):V(NaH2 PO4-Na2HPO4)=60:40. The method is simple,rapid and reproducible.
1-Dimethyl-3-phenylpropylamine enantiomer was separated with hydroxypropyl-β-cyclodextrin(HP-β-CD) as chiral selector by means of pressurized capillary electrochromatography(pCEC). The optimal experimental conditions are HP-β-CD concentration 10 g/L,background buffer pH=7.6,capillary temperature 16℃,voltage 10 kV,and the mobile phase consisted of a solution of acetonitrile and phosphate at a volume ratio of V(CH3CN):V(NaH2 PO4-Na2HPO4)=60:40. The method is simple,rapid and reproducible.
