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2010 Volume 27 Issue 10
2010, 27(10): 1117-1123
doi: 10.3724/SP.J.1095.2010.90839
Abstract:
This paper summarized the preparation methods and properties of diamond like carbon films(DLC film) as well as their modified sensors.The application of DLC films modified sensors in bioassay,electrochemical microgravimetry,metal tracing,H+ ion selective field-effect transistor(pH-ISFET),gas detection and so on is introduced and the prospects of application of these sensors in electrochemical area are also.
This paper summarized the preparation methods and properties of diamond like carbon films(DLC film) as well as their modified sensors.The application of DLC films modified sensors in bioassay,electrochemical microgravimetry,metal tracing,H+ ion selective field-effect transistor(pH-ISFET),gas detection and so on is introduced and the prospects of application of these sensors in electrochemical area are also.
2010, 27(10): 1124-1128
doi: 10.3724/SP.J.1095.2010.90396
Abstract:
The direct oxidation of benzyl alcohol to phenyl aldehyde was studied with chloridized metallic porphyrin(MnTPPCl)/ionic liquid(ILs)/oxidant catalysts. The effects of temperature,MnTPPCl,various oxidation agents and the role of axial ligands on the yield were examined. The results showed that the yield and the selectivity of phenyl aldehyde can be both more than 99% in half an hour under the novel catalytic system MnTPPCl/[Bmim]HSO4/K2S2O8. The catalytic system without any organic solvents can be reused for many times and get a good performance.
The direct oxidation of benzyl alcohol to phenyl aldehyde was studied with chloridized metallic porphyrin(MnTPPCl)/ionic liquid(ILs)/oxidant catalysts. The effects of temperature,MnTPPCl,various oxidation agents and the role of axial ligands on the yield were examined. The results showed that the yield and the selectivity of phenyl aldehyde can be both more than 99% in half an hour under the novel catalytic system MnTPPCl/[Bmim]HSO4/K2S2O8. The catalytic system without any organic solvents can be reused for many times and get a good performance.
2010, 27(10): 1129-1132
doi: 10.3724/SP.J.1095.2010.90746
Abstract:
The rheological behavior of interface-bonded metallocene and polyethylene/polymerizable modified montmoillonite(mPE/P-MMT) nanocomposite had been studied.It was found that there was cross-linking structure formed by PE matrix and P-MMTs;and mPE/P-MMT nanocomposite had higher melting strength compared with mPE matrix and conventional metallocene bonded polyethylene/dodecylammonium modified montmoillonite(mPE/12-MMT) composite.The melting strength of mPE/P-MMT at 190℃ was 12.0 cN.Supercritical carbon dioxide was used as foaming agent for foaming the samples.According to the results,higher volume expansion ratio,as much as 14.7,was obtained for the mPE/P-MMT sample compared with others.The optimum temperature for the foaming process on mPE/P-MMT nanocomposite was 142℃.
The rheological behavior of interface-bonded metallocene and polyethylene/polymerizable modified montmoillonite(mPE/P-MMT) nanocomposite had been studied.It was found that there was cross-linking structure formed by PE matrix and P-MMTs;and mPE/P-MMT nanocomposite had higher melting strength compared with mPE matrix and conventional metallocene bonded polyethylene/dodecylammonium modified montmoillonite(mPE/12-MMT) composite.The melting strength of mPE/P-MMT at 190℃ was 12.0 cN.Supercritical carbon dioxide was used as foaming agent for foaming the samples.According to the results,higher volume expansion ratio,as much as 14.7,was obtained for the mPE/P-MMT sample compared with others.The optimum temperature for the foaming process on mPE/P-MMT nanocomposite was 142℃.
2010, 27(10): 1133-1137
doi: 10.3724/SP.J.1095.2010.90682
Abstract:
The volume ratio of the emulsion before and after centrifugation is defined as centrifugal coefficient Vr,and the stability of the acrylamide and its derivatives inverse emulsion are evaluated by Vr.The results indicated that when Vr is larger,the inverse emulsion system is more stability.The stability of acrylamide and its derivatives inverse emulsions,prepared with surfactants consisting of lipophilic Span80/Span85 and hydrophilic tween80,was characterized by Vr.It is found that a positive correlation relationship exists between Vr and the mass fraction of oil phase.At a fixed mass fraction of oil phase,Vr is related not only to the hydrophilic-lipophilic balance(HLB) value of the three surfactants composite,but also to the concentration and type of acrylamide and its derivatives.When HLB value is about 4.20,the emulsion is stable;When the mass fraction of acryloyloxyethyl trimethyl ammonium chloride(DAC) in the aqueous phase is higher than 24%,the stable emulsion exist;When the mass fraction of DAC is lower than 24%,with the increase of DAC mass fraction in the aqueous phase,the inverse emulsion stability is improved too.It is observed that when Vr is greater than 0.95 by centrifuging for 3 min at 15000 r/min,the inverse emulsion of acrylamide and its derivatives is extremely stable,and the separation of emulsion phase did not occur in reserve even after half a year.
The volume ratio of the emulsion before and after centrifugation is defined as centrifugal coefficient Vr,and the stability of the acrylamide and its derivatives inverse emulsion are evaluated by Vr.The results indicated that when Vr is larger,the inverse emulsion system is more stability.The stability of acrylamide and its derivatives inverse emulsions,prepared with surfactants consisting of lipophilic Span80/Span85 and hydrophilic tween80,was characterized by Vr.It is found that a positive correlation relationship exists between Vr and the mass fraction of oil phase.At a fixed mass fraction of oil phase,Vr is related not only to the hydrophilic-lipophilic balance(HLB) value of the three surfactants composite,but also to the concentration and type of acrylamide and its derivatives.When HLB value is about 4.20,the emulsion is stable;When the mass fraction of acryloyloxyethyl trimethyl ammonium chloride(DAC) in the aqueous phase is higher than 24%,the stable emulsion exist;When the mass fraction of DAC is lower than 24%,with the increase of DAC mass fraction in the aqueous phase,the inverse emulsion stability is improved too.It is observed that when Vr is greater than 0.95 by centrifuging for 3 min at 15000 r/min,the inverse emulsion of acrylamide and its derivatives is extremely stable,and the separation of emulsion phase did not occur in reserve even after half a year.
2010, 27(10): 1138-1143
doi: 10.3724/SP.J.1095.2010.90835
Abstract:
A novel conjugated polymer containing azobenzene and 1,3,4-oxadiazole units(LPOXD) was synthesized.The structure of the LPOXD was charactered by FT-IR,UV-Vis,1H NMR,GPC,TGA and DSC.The results indicate that the intrinsic viscosity of the LPOXD is 0.02960 L/g,and its Mw and molecular mass distribution or polydispersity index(PDI) values are 8500 g/mol and 1.55,respectively.A 5% mass loss of the LPOXD occurred at 290℃.The glass-transition temperature(Tg) is 92.8℃.The introduction of long side chain of alkoxy significantly improved LPOXD's solubility in common organic solvents such as chloroform,tetrahydrofuran,and so on.Furthermore,the optical and electrochemical properties of the LPOXD were investigated throughly by UV-Vis absorption spectroscopy,fluorescence emission spectroscopy and cyclic voltammetry. The results indicate that the azobenzene in the LPOXD involve a trans-cis photoisomerization under the radiation of 365 nm UV light. A wide fluorescence peak of the LPOXD appeared in the wavelength range of blue and purple light under excitaion at 350 nm. Cyclic voltammetry reveals that the LUMO and HOMO energies of the LPOXD are-5.96 eV and-3.17 eV,respectively.
A novel conjugated polymer containing azobenzene and 1,3,4-oxadiazole units(LPOXD) was synthesized.The structure of the LPOXD was charactered by FT-IR,UV-Vis,1H NMR,GPC,TGA and DSC.The results indicate that the intrinsic viscosity of the LPOXD is 0.02960 L/g,and its Mw and molecular mass distribution or polydispersity index(PDI) values are 8500 g/mol and 1.55,respectively.A 5% mass loss of the LPOXD occurred at 290℃.The glass-transition temperature(Tg) is 92.8℃.The introduction of long side chain of alkoxy significantly improved LPOXD's solubility in common organic solvents such as chloroform,tetrahydrofuran,and so on.Furthermore,the optical and electrochemical properties of the LPOXD were investigated throughly by UV-Vis absorption spectroscopy,fluorescence emission spectroscopy and cyclic voltammetry. The results indicate that the azobenzene in the LPOXD involve a trans-cis photoisomerization under the radiation of 365 nm UV light. A wide fluorescence peak of the LPOXD appeared in the wavelength range of blue and purple light under excitaion at 350 nm. Cyclic voltammetry reveals that the LUMO and HOMO energies of the LPOXD are-5.96 eV and-3.17 eV,respectively.
2010, 27(10): 1144-1148
doi: 10.3724/SP.J.1095.2010.90716
Abstract:
Grafting of methyl methacrylate (MMA) onto chloroprene latex was carried out by emulsion polymerization. FTIR and 1H NMR confirmed that the grafted polymer was formed.Effects of the reaction temperature,the emulsifier concentration,the initiator concentration and the monomer concentration on the apparent polymerization rates were investigated. The results showed that the monomer conversion and the grafting efficiency could reach 99.1%,54.9%,respectively,under the conditions where the reaction temperature was 50℃,the dosage of initiator tert-butyl hydroperoxide/tetraethylenepentamine(t-BHP/TEPA) was 0.5% (based on the mass of dry chlorene rubber latex(CRL)),mass ratio of monomer to polymer was 3:5,and the amount of emulsifier sodium dodecylbenzenesulfonate(DSB) was 1% (based on the mass of monomer). The kinetics equation Rp=Kc(E)0.15c(I)0.30c(MMA)1.41,where K is a constant,was obtained. The overall activation energy for the polymerization process was 60.2 kJ/mol within 40~55℃. The graftcopolymerization reaction follows the free radical mechanism generally.
Grafting of methyl methacrylate (MMA) onto chloroprene latex was carried out by emulsion polymerization. FTIR and 1H NMR confirmed that the grafted polymer was formed.Effects of the reaction temperature,the emulsifier concentration,the initiator concentration and the monomer concentration on the apparent polymerization rates were investigated. The results showed that the monomer conversion and the grafting efficiency could reach 99.1%,54.9%,respectively,under the conditions where the reaction temperature was 50℃,the dosage of initiator tert-butyl hydroperoxide/tetraethylenepentamine(t-BHP/TEPA) was 0.5% (based on the mass of dry chlorene rubber latex(CRL)),mass ratio of monomer to polymer was 3:5,and the amount of emulsifier sodium dodecylbenzenesulfonate(DSB) was 1% (based on the mass of monomer). The kinetics equation Rp=Kc(E)0.15c(I)0.30c(MMA)1.41,where K is a constant,was obtained. The overall activation energy for the polymerization process was 60.2 kJ/mol within 40~55℃. The graftcopolymerization reaction follows the free radical mechanism generally.
2010, 27(10): 1149-1155
doi: 10.3724/SP.J.1095.2010.90878
Abstract:
Trehalose and ceramide both play important roles in retaining skin water. With an X-ray scattering instrument,we studied the interaction between ceramide E and trehalose systematically in the course of drying and heating-cooling scan. It was found that ceramide E,similar to lipids in membrane,was difficult to crystallize in the presence of trehalose.Similarly,ceramide also suppresses the crystallization of trehalose during drying and therefore prevents water loose. Furthermore,after cooling from 105℃ to room temperature with the presence of trehalose,the freeze-dried ceramide formed a structure similar to that of stratum corneum in human skin in which both liquid and orthorhombic crystal exist. It is the first time to be found that trehalose,in stead of other components in skin,help ceramide to be organized by the form in the real human skin.
Trehalose and ceramide both play important roles in retaining skin water. With an X-ray scattering instrument,we studied the interaction between ceramide E and trehalose systematically in the course of drying and heating-cooling scan. It was found that ceramide E,similar to lipids in membrane,was difficult to crystallize in the presence of trehalose.Similarly,ceramide also suppresses the crystallization of trehalose during drying and therefore prevents water loose. Furthermore,after cooling from 105℃ to room temperature with the presence of trehalose,the freeze-dried ceramide formed a structure similar to that of stratum corneum in human skin in which both liquid and orthorhombic crystal exist. It is the first time to be found that trehalose,in stead of other components in skin,help ceramide to be organized by the form in the real human skin.
2010, 27(10): 1156-1160
doi: 10.3724/SP.J.1095.2010.90745
Abstract:
Hydrodechlorination of CCl4 over Pt/Al2O3 and Pt-Cu/Al2O3 bimetallic catalysts was studied. The influence of reduction temperature of the catalysts on catalytic performance was investigated. CHCl3 was the main product over Pt/Al2O3,but products varied with reduction temperature over Pt-Cu/Al2O3. The main product was CHCl3 over Pt-Cu/Al2O3 reduced at 400℃,while the main product was CCl2 CCl2 over the catalyst reduced at 800℃.Hydrodechlorination of CCl4 is a strongly exothermic reaction,which leads to local overheating on the surface of catalysts. C2 products may carbonize on overheated sites and cover the active sites,which resulted in deactivation of the catalysts.The stability of catalysts can be improved by adding CH3OH as solvent,which entrapped reaction heat.In addition,the selectivity towards CCl2 CCl2 was also increased by adding CH3OH.
Hydrodechlorination of CCl4 over Pt/Al2O3 and Pt-Cu/Al2O3 bimetallic catalysts was studied. The influence of reduction temperature of the catalysts on catalytic performance was investigated. CHCl3 was the main product over Pt/Al2O3,but products varied with reduction temperature over Pt-Cu/Al2O3. The main product was CHCl3 over Pt-Cu/Al2O3 reduced at 400℃,while the main product was CCl2 CCl2 over the catalyst reduced at 800℃.Hydrodechlorination of CCl4 is a strongly exothermic reaction,which leads to local overheating on the surface of catalysts. C2 products may carbonize on overheated sites and cover the active sites,which resulted in deactivation of the catalysts.The stability of catalysts can be improved by adding CH3OH as solvent,which entrapped reaction heat.In addition,the selectivity towards CCl2 CCl2 was also increased by adding CH3OH.
2010, 27(10): 1161-1164
doi: 10.3724/SP.J.1095.2010.90876
Abstract:
A facile synthetic method for thienopyridine derivatives was developed via the reaction of 2-aminothiophenes with acetoacetic ester and tin tetrachloride under heating.Four thienopyridine derivatives were obtained.The structures of the target compounds were determined by means of IR,1H NMR,MS and elemental analysis.Preliminary biological activities of the four thienopyridine derivatives showed that most of them display high fungicidal activities and a certain extent of herbicidal activities as well.
A facile synthetic method for thienopyridine derivatives was developed via the reaction of 2-aminothiophenes with acetoacetic ester and tin tetrachloride under heating.Four thienopyridine derivatives were obtained.The structures of the target compounds were determined by means of IR,1H NMR,MS and elemental analysis.Preliminary biological activities of the four thienopyridine derivatives showed that most of them display high fungicidal activities and a certain extent of herbicidal activities as well.
2010, 27(10): 1165-1171
doi: 10.3724/SP.J.1095.2010.90820
Abstract:
Eleven 1-(morpholinomethyl)-3-(3,4,5-trimethoxyphenyl)-4-substitute deneamino-1,2,4 triazole-5-thiones were designed and synthesized by means of an ultrasonic radiation method and a traditional heating process.Their structures were characterized by 1H NMR,13C NMR,IR and elemental analyses.Preliminary bioassay shows that some of them exhibit certain inactivities to Cucumber mosaic virus(CMV).
Eleven 1-(morpholinomethyl)-3-(3,4,5-trimethoxyphenyl)-4-substitute deneamino-1,2,4 triazole-5-thiones were designed and synthesized by means of an ultrasonic radiation method and a traditional heating process.Their structures were characterized by 1H NMR,13C NMR,IR and elemental analyses.Preliminary bioassay shows that some of them exhibit certain inactivities to Cucumber mosaic virus(CMV).
2010, 27(10): 1172-1176
doi: 10.3724/SP.J.1095.2010.90570
Abstract:
The synergistic effect of Ce2O3 in ammonium polyphosphate-pentaeruthritol-melamine(APP-PERMA) intumescent flame retardant (IFR) system with ammonium polyphosphate (APP) for acid source,pentaeruthritol(PER) for carbon source and melamine (MA) for gas source was investigated by thermogravimetry analysis(TGA) and Fourier transform infrared spectroscopy(FTIR).It shows that Ce2O3 increases the degradation and accelerates the production of inorganic acid during 300~400℃.Ce2O3 changes the degradation time of IFR,however,it does not change the process of the degradation.Apparent activation energy analysis shows that Ce2O3 increases the apparent activation energy of IFR in the first decompose stage from 65.73 kJ/mol to 73.47 kJ/mol,and reduces it in the second,third and fourth stages from 167.46,135.13 and 141.34 kJ/mol to 85.25,96.08 and 58.18 kJ/mol,respectively.TGA shows that there is a great effect to the residue of IFR in every decompose stage when Ce2O3 is added.
The synergistic effect of Ce2O3 in ammonium polyphosphate-pentaeruthritol-melamine(APP-PERMA) intumescent flame retardant (IFR) system with ammonium polyphosphate (APP) for acid source,pentaeruthritol(PER) for carbon source and melamine (MA) for gas source was investigated by thermogravimetry analysis(TGA) and Fourier transform infrared spectroscopy(FTIR).It shows that Ce2O3 increases the degradation and accelerates the production of inorganic acid during 300~400℃.Ce2O3 changes the degradation time of IFR,however,it does not change the process of the degradation.Apparent activation energy analysis shows that Ce2O3 increases the apparent activation energy of IFR in the first decompose stage from 65.73 kJ/mol to 73.47 kJ/mol,and reduces it in the second,third and fourth stages from 167.46,135.13 and 141.34 kJ/mol to 85.25,96.08 and 58.18 kJ/mol,respectively.TGA shows that there is a great effect to the residue of IFR in every decompose stage when Ce2O3 is added.
2010, 27(10): 1177-1181
doi: 10.3724/SP.J.1095.2010.90804
Abstract:
A Fe3+-doped nanosized TiO2 photocatalyst was synthesized from a sol-gel based self-propagating high-temperature synthesis process(SHS) with TiCl4 as the raw material.Its photocatalytic activity was studied by probing the degradation of methylene blue(MB) under different light irradiations including sunlight,low and high pressure mercury lamps.XRD and SEM results indicate that the as-prepared nanoscale TiO2 powder is a porous anatase material after SHS at 350℃ and heat-treatment at 500℃.The optimal precursor molar ratio of n(Ti):n(citric acid):n(NH4NO3) is 1:3:5,the particle size is~20 nm.Experimental results show that the highest photocatalytic activity of Fe3+-doped TiO2 could be achieved when the molar ratio of Fe3+ to TiO2is 0.02%.Removing rate of MB was 96.1% with Fe3+-doped TiO2 as catalyst and sunlight as light source,which is 1.78 times of that of pure TiO2.
A Fe3+-doped nanosized TiO2 photocatalyst was synthesized from a sol-gel based self-propagating high-temperature synthesis process(SHS) with TiCl4 as the raw material.Its photocatalytic activity was studied by probing the degradation of methylene blue(MB) under different light irradiations including sunlight,low and high pressure mercury lamps.XRD and SEM results indicate that the as-prepared nanoscale TiO2 powder is a porous anatase material after SHS at 350℃ and heat-treatment at 500℃.The optimal precursor molar ratio of n(Ti):n(citric acid):n(NH4NO3) is 1:3:5,the particle size is~20 nm.Experimental results show that the highest photocatalytic activity of Fe3+-doped TiO2 could be achieved when the molar ratio of Fe3+ to TiO2is 0.02%.Removing rate of MB was 96.1% with Fe3+-doped TiO2 as catalyst and sunlight as light source,which is 1.78 times of that of pure TiO2.
2010, 27(10): 1182-1187
doi: 10.3724/SP.J.1095.2010.90877
Abstract:
TiO2-Al2O3 catalyst support was prepared by the sol-gel method and NiO/WO3/TiO2-Al2O3 catalyst was prepared by stepwise impregnation.Hydroisomerization of n-heptane over the NiO/WO3/TiO2-Al2O3 catalyst was investigated in a continuous flow fixed-bed reactor under atmospheric pressure.The catalysts were characterized using XRD and BET surface area.The effects of WO3 content,Ni content, calcination temperature,reduction temperature,reaction temperature on the catalytic performance were studied systematically.The result showed that when the mass fraction of WO3 and Ni in the catalyst was 25% and 10%,respectively,the highest catalytic activity of NiO/WO3/TiO2-Al2O3 could be achieved. The conversion of n-heptane is 15.50% while the isomerization selectivity of i-heptane can reach 84.06%.
TiO2-Al2O3 catalyst support was prepared by the sol-gel method and NiO/WO3/TiO2-Al2O3 catalyst was prepared by stepwise impregnation.Hydroisomerization of n-heptane over the NiO/WO3/TiO2-Al2O3 catalyst was investigated in a continuous flow fixed-bed reactor under atmospheric pressure.The catalysts were characterized using XRD and BET surface area.The effects of WO3 content,Ni content, calcination temperature,reduction temperature,reaction temperature on the catalytic performance were studied systematically.The result showed that when the mass fraction of WO3 and Ni in the catalyst was 25% and 10%,respectively,the highest catalytic activity of NiO/WO3/TiO2-Al2O3 could be achieved. The conversion of n-heptane is 15.50% while the isomerization selectivity of i-heptane can reach 84.06%.
2010, 27(10): 1188-1191
doi: 10.3724/SP.J.1095.2010.90832
Abstract:
Polyvinylpyrrolidone(PVP) nanofibers loaded on kryptol were fabricated from PVP sol via an electrospinning technique,followed by preoxidation at 250℃ and carbonization at 850℃.To obtain TiO2 nanoparticles loaded on these carbon nanofibers,the carbon nanofibers were firstly soaked by titanium n-butyloxide(Ti (OC4 H9n)4) and subsequently heat-treated at 200℃ and calcined at 550℃.The morphologies and structure of the products were investigated by scanning electron microscopy(SEM),Fourier transform infrared spectrometry(FT-IR),and X-ray diffraction(XRD). TiO2 loaded on carbon nanofibers were used to study the degradation of methylene blue(100 mL 2.0 mg/L methylene blue) under UV irradiation for 40 min. The obtained nanocomposite exhibited a higher photo-catalytic activity and the degradation percentage of methylene blue was higher than 75%.
Polyvinylpyrrolidone(PVP) nanofibers loaded on kryptol were fabricated from PVP sol via an electrospinning technique,followed by preoxidation at 250℃ and carbonization at 850℃.To obtain TiO2 nanoparticles loaded on these carbon nanofibers,the carbon nanofibers were firstly soaked by titanium n-butyloxide(Ti (OC4 H9n)4) and subsequently heat-treated at 200℃ and calcined at 550℃.The morphologies and structure of the products were investigated by scanning electron microscopy(SEM),Fourier transform infrared spectrometry(FT-IR),and X-ray diffraction(XRD). TiO2 loaded on carbon nanofibers were used to study the degradation of methylene blue(100 mL 2.0 mg/L methylene blue) under UV irradiation for 40 min. The obtained nanocomposite exhibited a higher photo-catalytic activity and the degradation percentage of methylene blue was higher than 75%.
2010, 27(10): 1192-1198
doi: 10.3724/SP.J.1095.2010.90855
Abstract:
The interaction between amidocaproic acid (ACA) and bovine serum albumin(BSA) was investigated by spectroscopic techniques including fluorescence,UV visible absorption and circular dichroism (CD) spectroscopies under simulative physiological conditions. The fluorescence quenching mechanism of BSA by ACA could be attributed to a dynamic quenching according to the Stern-Volmer equation and UV absorption spectra of BSA. Hydrogen bondings and van der Waals interactions are responsible for their interaction on the basis of the calculated thermodynamic parameters,binding constants and binding site numbers. A 2.3 nm binding distance between ACA and BSA was obtained based on the theory of Förster's non-radiation energy transfer.From displacement experiments it was identified that ACA binds to protein BSA at site I. Moreover,CD spectra demonstrated that the second structure of BSA induced a slight structural change after binding ACA.
The interaction between amidocaproic acid (ACA) and bovine serum albumin(BSA) was investigated by spectroscopic techniques including fluorescence,UV visible absorption and circular dichroism (CD) spectroscopies under simulative physiological conditions. The fluorescence quenching mechanism of BSA by ACA could be attributed to a dynamic quenching according to the Stern-Volmer equation and UV absorption spectra of BSA. Hydrogen bondings and van der Waals interactions are responsible for their interaction on the basis of the calculated thermodynamic parameters,binding constants and binding site numbers. A 2.3 nm binding distance between ACA and BSA was obtained based on the theory of Förster's non-radiation energy transfer.From displacement experiments it was identified that ACA binds to protein BSA at site I. Moreover,CD spectra demonstrated that the second structure of BSA induced a slight structural change after binding ACA.
2010, 27(10): 1199-1203
doi: 10.3724/SP.J.1095.2010.90671
Abstract:
A series of amphiphilic azobenzene derivatives were synthesized(including CH3-Azo,COOH-Azo,CH3O-Azo and SO3H-Azo) and their aggregation behaviors were studied in cyclohexane.Transition electron microscope(TEM) observations revealed that hollow spherical,rod-like and tubular aggregations of CH3OAzo,COOH-Azo and SO3H-Azo,respectively,could be formed in the solvent.All four substituted azobenzenes show similar absorption bands around 350 nm in UV-Vis spectra and emit the same 625 nm fluorescence despite of the different natures of the four substitutes.The later might be ascribed to their aggregation behaviors.It is believed that the synergetic effect between the substitutes and hydrophobic chains among the supramolecular interactions in cyclohexane causes their morphological variations.
A series of amphiphilic azobenzene derivatives were synthesized(including CH3-Azo,COOH-Azo,CH3O-Azo and SO3H-Azo) and their aggregation behaviors were studied in cyclohexane.Transition electron microscope(TEM) observations revealed that hollow spherical,rod-like and tubular aggregations of CH3OAzo,COOH-Azo and SO3H-Azo,respectively,could be formed in the solvent.All four substituted azobenzenes show similar absorption bands around 350 nm in UV-Vis spectra and emit the same 625 nm fluorescence despite of the different natures of the four substitutes.The later might be ascribed to their aggregation behaviors.It is believed that the synergetic effect between the substitutes and hydrophobic chains among the supramolecular interactions in cyclohexane causes their morphological variations.
2010, 27(10): 1204-1208
doi: 10.3724/SP.J.1095.2010.90732
Abstract:
ZnO nanoparticles were prepared from H2C2O4·2H2O and Zn(Ac)2·2H2O,and characterized by transmission electron microscope(TEM) and X-ray diffraction(XRD).Obained ZnO nanoparticles were used to fabricate a mixed carbon paste electrode.The electrochemical investigation of haemachrome chloride on a nano-ZnO mixed carbon paste electrode was conducted with cyclic voltammetry and differential pulse voltammetry.Compared to the commercial ZnO particles and the bare carbon paste electrode,the ZnO nanoparticle mixed carbon paste electrode possesses electrocatalytic properties toward haemachrome chloride due to the significant increase of peak current and the negative shift of peak potential.After accumulation at -0.30 V for 30 s in the phosphate buffer at pH=9.18,a sensitive reduction peak located at -0.44 V was employed for the determination of haemachrome chloride.Under optimum conditions,the reduction peak current was proportional to haemachrome chloride concentration in the range of 3.1 ×10-9~3.1 ×10-7 mol/L,with a detection limit of 1.5 × 10-9 mol/L.The proposed method was successfully applied to the determination of haemachrome chloride in haematic tonic(Red hearts K).
ZnO nanoparticles were prepared from H2C2O4·2H2O and Zn(Ac)2·2H2O,and characterized by transmission electron microscope(TEM) and X-ray diffraction(XRD).Obained ZnO nanoparticles were used to fabricate a mixed carbon paste electrode.The electrochemical investigation of haemachrome chloride on a nano-ZnO mixed carbon paste electrode was conducted with cyclic voltammetry and differential pulse voltammetry.Compared to the commercial ZnO particles and the bare carbon paste electrode,the ZnO nanoparticle mixed carbon paste electrode possesses electrocatalytic properties toward haemachrome chloride due to the significant increase of peak current and the negative shift of peak potential.After accumulation at -0.30 V for 30 s in the phosphate buffer at pH=9.18,a sensitive reduction peak located at -0.44 V was employed for the determination of haemachrome chloride.Under optimum conditions,the reduction peak current was proportional to haemachrome chloride concentration in the range of 3.1 ×10-9~3.1 ×10-7 mol/L,with a detection limit of 1.5 × 10-9 mol/L.The proposed method was successfully applied to the determination of haemachrome chloride in haematic tonic(Red hearts K).
2010, 27(10): 1209-1214
doi: 10.3724/SP.J.1095.2010.90828
Abstract:
To study the content variation of ginsenosides after the combination of ginseng with Zingiber officinale Rosc or Radix Paeoniae Rubra,a high performance liquid chromatography-electrospray ionization spectrometric(HPLC-ESI-MS) method was used to analyze and compare the ginsenosides in the decoction. The experimental results show that the contents of ginsenosides decreased along with the increased amount of Zingiber officinale Rosc,while the stripping of ginsenosides was promoted by a small amount of Radix Paeoniae Rubra. In addition,the total antioxidant activity of n-butanol and water extracts from the single and compatible decoctions of ginseng was also determined by ferric reducing antioxidant power(FRAP) method.With ascorbic acid(500 μmol/L) as control,the anti-oxidation of compatible decoction of ginseng with Zingiber officinale Rosc/Radix Paeoniae Rubra was higher than that of the single decoction of ginseng;and the FRAP values of n-butanol extracts from the compatible decoction of ginseng with Zingiber officinale Rosc or Radix Paeoniae Rubra were 1562.29 and 2969.78 μmol/L,respectively,greater than the sum of single decoction of ginseng with Zingiber officinale Rosc(1260.27 μmol/L)/Radix Paeoniae Rubra(2502.07 μmol/L),indicating that the antioxidant activity of n-butanol extract from compatible decoction was better.
To study the content variation of ginsenosides after the combination of ginseng with Zingiber officinale Rosc or Radix Paeoniae Rubra,a high performance liquid chromatography-electrospray ionization spectrometric(HPLC-ESI-MS) method was used to analyze and compare the ginsenosides in the decoction. The experimental results show that the contents of ginsenosides decreased along with the increased amount of Zingiber officinale Rosc,while the stripping of ginsenosides was promoted by a small amount of Radix Paeoniae Rubra. In addition,the total antioxidant activity of n-butanol and water extracts from the single and compatible decoctions of ginseng was also determined by ferric reducing antioxidant power(FRAP) method.With ascorbic acid(500 μmol/L) as control,the anti-oxidation of compatible decoction of ginseng with Zingiber officinale Rosc/Radix Paeoniae Rubra was higher than that of the single decoction of ginseng;and the FRAP values of n-butanol extracts from the compatible decoction of ginseng with Zingiber officinale Rosc or Radix Paeoniae Rubra were 1562.29 and 2969.78 μmol/L,respectively,greater than the sum of single decoction of ginseng with Zingiber officinale Rosc(1260.27 μmol/L)/Radix Paeoniae Rubra(2502.07 μmol/L),indicating that the antioxidant activity of n-butanol extract from compatible decoction was better.
2010, 27(10): 1215-1220
doi: 10.3724/SP.J.1095.2010.90831
Abstract:
In a pH 5.0~7.6 Britton-Robinson(BR) buffer medium,furosemide(FUR) reacted with Pd (Ⅱ) to form a 1:1 anionic chelate,which further reacted with some basic triphenylmethane dyes(BTPMD) such as ethyl violet(EV),crystal violet(CV),methyl violet(MV),methyl green(MeG),and brilliant green(BG) to form 1:1 ionic complexes.The absorption spectra of the dyes were changed and fading peak are 595 nm for EV and CV systems,580 nm for MV system,615 nm for BG system and 630 nm for MeG system.There was an linearity between the concentrations of FUR and △A of the solutions at the maximum fading peaks.The quantitative determination ranges of five the triphenylmethane dyes were 2.0 × 10-7~4.0 × 10-6g/mL for EV system,3.0 × 10-7~8.0 × 10-6g/mL for CV system,4.0 × 10-7~4.0 × 10-6g/mL for MV system,4.0 × 10-7~7.0 × 10-6g/mL for BG system and 1.2 × 10-6~8.0 × 10-6g/mL for MeG system. Depending on the different dyes systems,the molar absorption coefficiencies(ε) of different systems were between 0.57 × 104~3.40 × 104L/(mol·cm) and the detection limit (3ε) was 6.0 × 10-8g/mL. A new spectrophotometry for the determination of FUR was set up based on above results. In the five systems,the optimal conditions of the reactions and the effects of external substances were investigated,the method has been applied to the determination of FUR in urine samples with satisfactory results. The mean recoveries ranged from 96.0% to 106.8%.
In a pH 5.0~7.6 Britton-Robinson(BR) buffer medium,furosemide(FUR) reacted with Pd (Ⅱ) to form a 1:1 anionic chelate,which further reacted with some basic triphenylmethane dyes(BTPMD) such as ethyl violet(EV),crystal violet(CV),methyl violet(MV),methyl green(MeG),and brilliant green(BG) to form 1:1 ionic complexes.The absorption spectra of the dyes were changed and fading peak are 595 nm for EV and CV systems,580 nm for MV system,615 nm for BG system and 630 nm for MeG system.There was an linearity between the concentrations of FUR and △A of the solutions at the maximum fading peaks.The quantitative determination ranges of five the triphenylmethane dyes were 2.0 × 10-7~4.0 × 10-6g/mL for EV system,3.0 × 10-7~8.0 × 10-6g/mL for CV system,4.0 × 10-7~4.0 × 10-6g/mL for MV system,4.0 × 10-7~7.0 × 10-6g/mL for BG system and 1.2 × 10-6~8.0 × 10-6g/mL for MeG system. Depending on the different dyes systems,the molar absorption coefficiencies(ε) of different systems were between 0.57 × 104~3.40 × 104L/(mol·cm) and the detection limit (3ε) was 6.0 × 10-8g/mL. A new spectrophotometry for the determination of FUR was set up based on above results. In the five systems,the optimal conditions of the reactions and the effects of external substances were investigated,the method has been applied to the determination of FUR in urine samples with satisfactory results. The mean recoveries ranged from 96.0% to 106.8%.
2010, 27(10): 1221-1224
doi: 10.3724/SP.J.1095.2010.90847
Abstract:
A facile method has been set up for the determination of cocaine (COC) and its metabolite ecgonine methyl ester(EME) in human urine by means of gas chromatography(GC) with a flame ionization detector(FID).The urine samples were prepared by liquid-liquid extraction(LLE). To improve the extraction efficiency,the experimental parameters of LLE,including extraction solvent and its amount,pH value of the urine sample and extraction time were investigated.The optimized conditions are:8.0 mL of chloroformisopropanol(volume ratio 9:1),was used extractant,the pH value of urine sample is around 9.5,the extraction temperature and time are 40℃ and 6 min,respectively.The intra-day precisions of COC and EME were 1.73% and 1.44% while the inter-day precisions of COC and EME were 2.57% and 2.89%,respectively.The limits of detection(LOD) for both were 0.04 mg/L. The derivatization of COC and EME in traditional detection process could be bypassed in this protocol. The results indicate that the developed method is rapid,accurate and sensitive,which can be used for the simultaneous determinations of COC and EME in urine samples for forensic applications.
A facile method has been set up for the determination of cocaine (COC) and its metabolite ecgonine methyl ester(EME) in human urine by means of gas chromatography(GC) with a flame ionization detector(FID).The urine samples were prepared by liquid-liquid extraction(LLE). To improve the extraction efficiency,the experimental parameters of LLE,including extraction solvent and its amount,pH value of the urine sample and extraction time were investigated.The optimized conditions are:8.0 mL of chloroformisopropanol(volume ratio 9:1),was used extractant,the pH value of urine sample is around 9.5,the extraction temperature and time are 40℃ and 6 min,respectively.The intra-day precisions of COC and EME were 1.73% and 1.44% while the inter-day precisions of COC and EME were 2.57% and 2.89%,respectively.The limits of detection(LOD) for both were 0.04 mg/L. The derivatization of COC and EME in traditional detection process could be bypassed in this protocol. The results indicate that the developed method is rapid,accurate and sensitive,which can be used for the simultaneous determinations of COC and EME in urine samples for forensic applications.
2010, 27(10): 1225-1229
doi: 10.3724/SP.J.1095.2010.90845
Abstract:
A new method using a microcolumn packed with nanometer TiO2 as solid-phase extractant was developed for the preconcentration and separation of trace amounts of Te(Ⅳ) prior to its measurement by ultraviolet spectrophotometry.Effects of pH,sample flow rate and volume,elution solution and coexisted ions on the recovery of the analytes were investigated.The sorption was optimized with respect to the pH,the maximum sorption was achieved from the solution of pH 8~9.5,and the adsorption percentage was 99%.Sorbed Te(Ⅳ) was desorbed in 2.0 mL of 0.5 mol/L NaOH,with an enrichment factor of 30.The detection limit(3σ) of the method for Te(Ⅳ) was 0.013 mg/L(n=13);and the relative standard deviation was 1.99% (n=13,c=30 mg/L).At room temperature,the dynamic saturated adsorption capacity was 37.02 mg/g.The proposed method was applied to the determination of trace amounts of Te(Ⅳ) in water samples,the determined values were in good agreement with the certified values.
A new method using a microcolumn packed with nanometer TiO2 as solid-phase extractant was developed for the preconcentration and separation of trace amounts of Te(Ⅳ) prior to its measurement by ultraviolet spectrophotometry.Effects of pH,sample flow rate and volume,elution solution and coexisted ions on the recovery of the analytes were investigated.The sorption was optimized with respect to the pH,the maximum sorption was achieved from the solution of pH 8~9.5,and the adsorption percentage was 99%.Sorbed Te(Ⅳ) was desorbed in 2.0 mL of 0.5 mol/L NaOH,with an enrichment factor of 30.The detection limit(3σ) of the method for Te(Ⅳ) was 0.013 mg/L(n=13);and the relative standard deviation was 1.99% (n=13,c=30 mg/L).At room temperature,the dynamic saturated adsorption capacity was 37.02 mg/g.The proposed method was applied to the determination of trace amounts of Te(Ⅳ) in water samples,the determined values were in good agreement with the certified values.
2010, 27(10): 1230-1234
doi: 10.3724/SP.J.1095.2010.90867
Abstract:
A novel method has been developed for the speciation of chromium in environmental water samples based on microemulsion extraction separation and preconcentration,and determination by double-slotted quartz tube atom trap-flame atomic absorption spectrometry (STAT-FAAS).In this method,Cr(Ⅲ) reacts with 8-hydroxyquinoline(8-HQ) yielding a hydrophobic complex,which then is extracted in the microemulsion phase,whereas Cr(Ⅵ) remained in aqueous phase.Thus,separation of Cr(Ⅲ) and Cr(Ⅵ) could be realized.Total chromium was determined after the reduction of Cr(Ⅵ) to Cr(Ⅲ) by using hydrogen peroxide as the reducing reagent.The main factors affecting the separation of Cr(Ⅲ) and Cr(Ⅵ) were optimized.The optimum conditions of the experiment are as follows,equilibration temperature and time are 80℃ and 10 min respectively,the pH of the system is 9.0,amounts of NH3-NH4 Cl buffer and 8-HQ are 2.0 mL and 0.05 mmol,respectively,and microemulsion is made of mixture of Triton X-100,n-pentanol,n-hexane and water at mass ratio of 3.0:15.0:1.5:4.0.Under the optimized conditions,the preconcentration system permitted an enrichment factor of 25 for chromium from the initial 50 mL sample solution to the final 2 mL concentrated solution;the linear concentration range was 2.5~500 μg/L for chromium.The limit of detection was 0.62 μg/L,and the relative standard deviation(n=10) was 3.8% for 10 μg/L Cr(Ⅲ) solution.The proposed procedure has been applied to the speciation of chromium in electroplating wastewater samples successfully.
A novel method has been developed for the speciation of chromium in environmental water samples based on microemulsion extraction separation and preconcentration,and determination by double-slotted quartz tube atom trap-flame atomic absorption spectrometry (STAT-FAAS).In this method,Cr(Ⅲ) reacts with 8-hydroxyquinoline(8-HQ) yielding a hydrophobic complex,which then is extracted in the microemulsion phase,whereas Cr(Ⅵ) remained in aqueous phase.Thus,separation of Cr(Ⅲ) and Cr(Ⅵ) could be realized.Total chromium was determined after the reduction of Cr(Ⅵ) to Cr(Ⅲ) by using hydrogen peroxide as the reducing reagent.The main factors affecting the separation of Cr(Ⅲ) and Cr(Ⅵ) were optimized.The optimum conditions of the experiment are as follows,equilibration temperature and time are 80℃ and 10 min respectively,the pH of the system is 9.0,amounts of NH3-NH4 Cl buffer and 8-HQ are 2.0 mL and 0.05 mmol,respectively,and microemulsion is made of mixture of Triton X-100,n-pentanol,n-hexane and water at mass ratio of 3.0:15.0:1.5:4.0.Under the optimized conditions,the preconcentration system permitted an enrichment factor of 25 for chromium from the initial 50 mL sample solution to the final 2 mL concentrated solution;the linear concentration range was 2.5~500 μg/L for chromium.The limit of detection was 0.62 μg/L,and the relative standard deviation(n=10) was 3.8% for 10 μg/L Cr(Ⅲ) solution.The proposed procedure has been applied to the speciation of chromium in electroplating wastewater samples successfully.
2010, 27(10): 1235-1237
doi: 10.3724/SP.J.1095.2010.90849
Abstract:
Acetonitrile-trioxymethylene was chosen to replace acetamide-paraformaldehyde for the synthesis of the intermediate hexahydro-1,3,5-triacetyl-s-triazine (TRAT),which was then nitrated by dinitrogen pentroxide to form hexogen(RDX). Under optimized synthetic conditions,a 95.2% yield of TRAT could be attained when the molar ratio of 1,3,5-trioxane to acetonitrile was 1:2,the molar ratio of H2SO4 to 1,3,5trioxane was 1:7.5,the reaction temperature was 75℃,the reaction time was 3 h, H2SO4 was chosen as catalyst and acetonitrile was used as both reactant and solvent.In the subsequent nitration process,carried at 45℃ for 1 h,a 87.2% yield of RDX could be achieved when the molar ratios of TRAT to N2O5 and N2O5 to HNO3 were 1:7 and 1:6,respectively. The overall yield of RDX was 83.0% for this new approach. This established method might be scaled up for industrial productions of RDX due to its simpleness in terms of post treatment and environmental benign.
Acetonitrile-trioxymethylene was chosen to replace acetamide-paraformaldehyde for the synthesis of the intermediate hexahydro-1,3,5-triacetyl-s-triazine (TRAT),which was then nitrated by dinitrogen pentroxide to form hexogen(RDX). Under optimized synthetic conditions,a 95.2% yield of TRAT could be attained when the molar ratio of 1,3,5-trioxane to acetonitrile was 1:2,the molar ratio of H2SO4 to 1,3,5trioxane was 1:7.5,the reaction temperature was 75℃,the reaction time was 3 h, H2SO4 was chosen as catalyst and acetonitrile was used as both reactant and solvent.In the subsequent nitration process,carried at 45℃ for 1 h,a 87.2% yield of RDX could be achieved when the molar ratios of TRAT to N2O5 and N2O5 to HNO3 were 1:7 and 1:6,respectively. The overall yield of RDX was 83.0% for this new approach. This established method might be scaled up for industrial productions of RDX due to its simpleness in terms of post treatment and environmental benign.
2010, 27(10): 1238-1240
doi: 10.3724/SP.J.1095.2010.90863
Abstract:
An edible perfume theaspirone,1-oxa-8-oxo-2,6,10,10-tetramethyl-spiro-[4,5]-6-decene,was synthesized from α-ionone with 52.6% overall yield via six steps including epoxiation by metachloroperbenzoic acid,ring-opening in the presence of sodium methoxide,selective reduction of carbon-carbon double bond catalyzed by Pd/C with ammoniumformate under ultrasonic irridiation,then reduction with sodium borohydride,intramolecular cyclodehydration and allylic oxidation catalyzed by acetylacetone cobalt(Ⅱ) with oxygen gas.The structures and compositions of the product and some intermediates were characterized by IR,1H NMR,MS and elemental analysis.
An edible perfume theaspirone,1-oxa-8-oxo-2,6,10,10-tetramethyl-spiro-[4,5]-6-decene,was synthesized from α-ionone with 52.6% overall yield via six steps including epoxiation by metachloroperbenzoic acid,ring-opening in the presence of sodium methoxide,selective reduction of carbon-carbon double bond catalyzed by Pd/C with ammoniumformate under ultrasonic irridiation,then reduction with sodium borohydride,intramolecular cyclodehydration and allylic oxidation catalyzed by acetylacetone cobalt(Ⅱ) with oxygen gas.The structures and compositions of the product and some intermediates were characterized by IR,1H NMR,MS and elemental analysis.
