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2008 Volume 25 Issue 12
2008, 25(12): 1381-1384
Abstract:
FITC(fluorescein isothiocyanate) that can be linked to lipase as a fluorescence probe was used to study the relationships among the activity of lipase,conformation,and fluorescence spectrum.The changes of activity and fluorescence spectrum of the labeled and unlabeled lipase were examined under various temperatures,pH and different concentrations of guanidine hydrochloride.The results demonstrated that compared with the unlabeled lipase,the thermal stability of the labeled lipase was improved,and it was completely inactive at 70℃.The stability of the labelled lipase at different pH was also increased.The activity of the labeled lipase would decrease under different concentrations of guanidine hydrochloride,and fluorescence spectrum of the labeled lipase could reflect the change of the activity.
FITC(fluorescein isothiocyanate) that can be linked to lipase as a fluorescence probe was used to study the relationships among the activity of lipase,conformation,and fluorescence spectrum.The changes of activity and fluorescence spectrum of the labeled and unlabeled lipase were examined under various temperatures,pH and different concentrations of guanidine hydrochloride.The results demonstrated that compared with the unlabeled lipase,the thermal stability of the labeled lipase was improved,and it was completely inactive at 70℃.The stability of the labelled lipase at different pH was also increased.The activity of the labeled lipase would decrease under different concentrations of guanidine hydrochloride,and fluorescence spectrum of the labeled lipase could reflect the change of the activity.
2008, 25(12): 1385-1388
Abstract:
Unsaturated polyester resin(UPR)/kaolinite intercalation nanocomposites were prepared by in situ polymerization through UP replacing DMSO in kaolinite/DMSO intercalation usher,which was prepared by sonochemistry technique.The structure of the nanocomposites was characterized by XRD and FTIR.The thermal stability,flame retardant and mechanical properties were also studied.The results show that the layered structure of kaolinite was exfoliated during the formation of unsaturated polyester.The decomposition and mass loss rate decreased by adding kaolinite.After adding a small amount of flame retardant,the nanocomposites are self-extinguished once being taken away from the fire,have no droping and heavy smoke while combusting,and the flame extended length is less than 5 mm.The mechanical properties of the nanocomposites have been improved compared with that of pure UP.All these results are from the kaolinite layers migrating to the surface of materials,which forms compact and hard char protection layer when combusting.
Unsaturated polyester resin(UPR)/kaolinite intercalation nanocomposites were prepared by in situ polymerization through UP replacing DMSO in kaolinite/DMSO intercalation usher,which was prepared by sonochemistry technique.The structure of the nanocomposites was characterized by XRD and FTIR.The thermal stability,flame retardant and mechanical properties were also studied.The results show that the layered structure of kaolinite was exfoliated during the formation of unsaturated polyester.The decomposition and mass loss rate decreased by adding kaolinite.After adding a small amount of flame retardant,the nanocomposites are self-extinguished once being taken away from the fire,have no droping and heavy smoke while combusting,and the flame extended length is less than 5 mm.The mechanical properties of the nanocomposites have been improved compared with that of pure UP.All these results are from the kaolinite layers migrating to the surface of materials,which forms compact and hard char protection layer when combusting.
2008, 25(12): 1389-1392
Abstract:
In the presence of triethylamine,the reaction of 2,4-disubstituted-2,3-dihydro-1,5-benzothia-zepine with α-chloro-2-phenyl-1,2,3-triazole-4-carbaldehyde oxime through 1,3-dipolar cycloadditon produces a series of 2-phenyl-1,2,3-triazol-4-yl[1,2,4] oxadiazolo[4,5-a][1,5] benzothiazepine derivatives.The compounds bearing benzothiazepine,1,2,3-triazole and 1,2,4-oxadiazole moieties may possess interesting bioactivities.
In the presence of triethylamine,the reaction of 2,4-disubstituted-2,3-dihydro-1,5-benzothia-zepine with α-chloro-2-phenyl-1,2,3-triazole-4-carbaldehyde oxime through 1,3-dipolar cycloadditon produces a series of 2-phenyl-1,2,3-triazol-4-yl[1,2,4] oxadiazolo[4,5-a][1,5] benzothiazepine derivatives.The compounds bearing benzothiazepine,1,2,3-triazole and 1,2,4-oxadiazole moieties may possess interesting bioactivities.
2008, 25(12): 1393-1398
Abstract:
Poly(DMDAAC-NVP-IOA) was prepared from dimethyldiallylammonium chloride(DMDAAC),N-vinyl pyrrolidone(NVP) and isooctyl acrylate(IOA) via radical micellar polymerization in water.The polyelectrolyte and hydrophobic association properties of the polymer were studied.The interactions of P(DMDAAC-NVP-IOA) with naproxen were investigated by IR,XRD and DSC.As the amount of P(DMDAAC-NVP-IOA) increased,the peak at 1 684 cm-1 assigned to the carbonyl of naproxen became broader and the peak intensity decreased.The diffraction peaks between 12° and 29° in the XRD pattern also became wider and even disappeared.There was only one transition observed by DSC with the increase of the amount of the polymer.All these results suggest the presence of interactions at molecular level between P(DMDAAC-NVP-IOA) and naproxen.Sustained-release tablets by naproxen were prepared from the copolymer and naproxen,and the drug release results suggest that the sustained-release tablets in the presence of P(DMDAAC-NVP-IOA) exhibit excellent properties in phosphate buffer,and the kinetics can be fit to a diffusion-erosion model.
Poly(DMDAAC-NVP-IOA) was prepared from dimethyldiallylammonium chloride(DMDAAC),N-vinyl pyrrolidone(NVP) and isooctyl acrylate(IOA) via radical micellar polymerization in water.The polyelectrolyte and hydrophobic association properties of the polymer were studied.The interactions of P(DMDAAC-NVP-IOA) with naproxen were investigated by IR,XRD and DSC.As the amount of P(DMDAAC-NVP-IOA) increased,the peak at 1 684 cm-1 assigned to the carbonyl of naproxen became broader and the peak intensity decreased.The diffraction peaks between 12° and 29° in the XRD pattern also became wider and even disappeared.There was only one transition observed by DSC with the increase of the amount of the polymer.All these results suggest the presence of interactions at molecular level between P(DMDAAC-NVP-IOA) and naproxen.Sustained-release tablets by naproxen were prepared from the copolymer and naproxen,and the drug release results suggest that the sustained-release tablets in the presence of P(DMDAAC-NVP-IOA) exhibit excellent properties in phosphate buffer,and the kinetics can be fit to a diffusion-erosion model.
2008, 25(12): 1399-1403
Abstract:
The damage of bovine serum albumin(BSA) molecules under the action of methylene blue(MB) activated by ultrasonic irradiation was detected by UV-Vis spectroscopy and fluorescence spectroscopy,and influencing factors such as ultrasonic irradiation time,MB concentration and pH value on the damage of BSA molecules were also investigated.The results show that under certain conditions,the damage of BSA molecules was enhanced with the increases of the ultrasonic irradiation time,MB concentration,and pH value,that is,UV-Vis spectra showed more and more obvious hyperchromic effect and fluorescence spectra exhibited more and more obvious quenching effect.In addition,the possible mechanism of sonodynamic damage of BSA molecules from MB activated by ultrasound was also discussed in this work.The result has certain significance for the application of photosensitive drugs to sonodynamic therapy(SDT).
The damage of bovine serum albumin(BSA) molecules under the action of methylene blue(MB) activated by ultrasonic irradiation was detected by UV-Vis spectroscopy and fluorescence spectroscopy,and influencing factors such as ultrasonic irradiation time,MB concentration and pH value on the damage of BSA molecules were also investigated.The results show that under certain conditions,the damage of BSA molecules was enhanced with the increases of the ultrasonic irradiation time,MB concentration,and pH value,that is,UV-Vis spectra showed more and more obvious hyperchromic effect and fluorescence spectra exhibited more and more obvious quenching effect.In addition,the possible mechanism of sonodynamic damage of BSA molecules from MB activated by ultrasound was also discussed in this work.The result has certain significance for the application of photosensitive drugs to sonodynamic therapy(SDT).
2008, 25(12): 1404-1408
Abstract:
The integrated pulsed amperometric detection(IPAD) was applied to the detection of phenylethylamine.At an appropriate potential,phenylethylamine responded sensitively at an Au-electrode.The main advantages are the high sensitivity,good reproducibility and stability.The method has the ability to keep the working electrode clean by the use of a high-frequent pulse waveform and a cleaning potential.In this article,the oxidation potential of phenylethylamine was determined by cyclic voltammetry,and the integrated pulsed amperometric parameters were studied.The proper parameters are:phenylethylamine should be oxidized under a potential of 0.650 V for 0.2 s,the optimum electrolyte is NaOH solution(pH=12.7),the range of linearity is 1.15×10-5~1.67×10-7 mol/L,the detection limit is 1.00×10-7 mol/L,and the average recovery is 95.8%.In addition,the interfering factors were also studied in this article.In conclusion,this method has a good reproducibility and it is easy,inexpensive and time saving.
The integrated pulsed amperometric detection(IPAD) was applied to the detection of phenylethylamine.At an appropriate potential,phenylethylamine responded sensitively at an Au-electrode.The main advantages are the high sensitivity,good reproducibility and stability.The method has the ability to keep the working electrode clean by the use of a high-frequent pulse waveform and a cleaning potential.In this article,the oxidation potential of phenylethylamine was determined by cyclic voltammetry,and the integrated pulsed amperometric parameters were studied.The proper parameters are:phenylethylamine should be oxidized under a potential of 0.650 V for 0.2 s,the optimum electrolyte is NaOH solution(pH=12.7),the range of linearity is 1.15×10-5~1.67×10-7 mol/L,the detection limit is 1.00×10-7 mol/L,and the average recovery is 95.8%.In addition,the interfering factors were also studied in this article.In conclusion,this method has a good reproducibility and it is easy,inexpensive and time saving.
2008, 25(12): 1409-1412
Abstract:
At 725℃,MgCl2-KCl-NaCl-CaCl2 molten salt was used for the electrolysis of magnesium chloride.Results show that in the course of magnesium electrolysis,cathode overvoltage ηc is not large,only 12~51 mV,the overvoltage of the electrolysis process is mainly caused by the anode;the diffusion-limited current id of the cathodic process is 1.56 A/cm2;the number of electron transfer of the cathodic process is 1.98;while there is a pre-conversion step MgCl+=Mg2++C1-before the reversible electron transfer step.CV was used to study magnesium ions behavior in the molten salt electrolyte with four different ratios of CaCl2.With changing CaCl2 from 10 percent to 40 percent,while maintaining MgCl2 to be 10 percent and the mass ratio of NaCl and KCl to be 6:1,as the amount of CaCl2 increased,magnesium ions integrate into the complexing anions,which are not easy to move.As a result,the migration current of magnesium ions decreases,the magnesium ions deposition potential gradually moves to the negative direction from-1.595 V to which codeposition of magnesium with Ca and Na takes place,cathodic peak current Ipc gradually increases,the absolute value of the difference between anodic peak potential and cathodic peak potential |φpa-φpc| gradually increases,and the reversibility of cathode discharge reaction gradually lowers.
At 725℃,MgCl2-KCl-NaCl-CaCl2 molten salt was used for the electrolysis of magnesium chloride.Results show that in the course of magnesium electrolysis,cathode overvoltage ηc is not large,only 12~51 mV,the overvoltage of the electrolysis process is mainly caused by the anode;the diffusion-limited current id of the cathodic process is 1.56 A/cm2;the number of electron transfer of the cathodic process is 1.98;while there is a pre-conversion step MgCl+=Mg2++C1-before the reversible electron transfer step.CV was used to study magnesium ions behavior in the molten salt electrolyte with four different ratios of CaCl2.With changing CaCl2 from 10 percent to 40 percent,while maintaining MgCl2 to be 10 percent and the mass ratio of NaCl and KCl to be 6:1,as the amount of CaCl2 increased,magnesium ions integrate into the complexing anions,which are not easy to move.As a result,the migration current of magnesium ions decreases,the magnesium ions deposition potential gradually moves to the negative direction from-1.595 V to which codeposition of magnesium with Ca and Na takes place,cathodic peak current Ipc gradually increases,the absolute value of the difference between anodic peak potential and cathodic peak potential |φpa-φpc| gradually increases,and the reversibility of cathode discharge reaction gradually lowers.
2008, 25(12): 1413-1416
Abstract:
Polyimides films were prepared from 3,3',4,4'-BPDA and three different diamines,4,4'-ODA,4,4'-DABP and DPEB with PA as end-capping.They were characterized by DMTA,TGA and mechanical analysis.The results show that the glass transition temperature of polyimides and the tensile strength of the films were improved when the phenylethynyl was a pendent group.When the content of the diamine DPEB increased,the glass transition temperature of cured polyimides DPEB/4,4'-ODA/3,3',4,4'-BPDA/PA increased from 315.3℃ to 354.0℃.The tensile strength of PPEIs also increased from 76.5 to 164.0 MPa.The weight loss temperature(T5%) of PIs was in a range of 491.9~499.8℃.The glass transition temperature of cured polyimides DPEB/4,4'-DABP/3,3',4,4'-BPDA/PA increased from 350.5℃ to 379.2℃.The tensile strength of PPEIs also increased from 106.5 to 129.8 MPa.The weight loss temperature(T5%) of PIs was in a range of 483.9~493.0℃.
Polyimides films were prepared from 3,3',4,4'-BPDA and three different diamines,4,4'-ODA,4,4'-DABP and DPEB with PA as end-capping.They were characterized by DMTA,TGA and mechanical analysis.The results show that the glass transition temperature of polyimides and the tensile strength of the films were improved when the phenylethynyl was a pendent group.When the content of the diamine DPEB increased,the glass transition temperature of cured polyimides DPEB/4,4'-ODA/3,3',4,4'-BPDA/PA increased from 315.3℃ to 354.0℃.The tensile strength of PPEIs also increased from 76.5 to 164.0 MPa.The weight loss temperature(T5%) of PIs was in a range of 491.9~499.8℃.The glass transition temperature of cured polyimides DPEB/4,4'-DABP/3,3',4,4'-BPDA/PA increased from 350.5℃ to 379.2℃.The tensile strength of PPEIs also increased from 106.5 to 129.8 MPa.The weight loss temperature(T5%) of PIs was in a range of 483.9~493.0℃.
2008, 25(12): 1417-1420
Abstract:
A new method for the determination of trace tin has been established.The method is based on the catalytic effect of Sn(Ⅳ) on the oxidation of 3-(3'-chlorophenyl)-5-(2'-aresenoxylphenylazo)rhodanine by potassium periodate in a buffer solution of potassium hydrogen phthalate-sodium hydroxide at pH=5.0,where the apparent active energy and reaction rate constant are calculated to be 51.20 kJ/mol and 1.23×10-2/s.The excitation and emission wave lengths are 308 nm/410 nm,the linear range is 0~0.01 ×10-6 g/mL,the detection limit is 1.65×1-9 g/mL.The method has been used to determine Sn(Ⅳ) in food and enviro-nmental water with satisfactory results after separation and enrichment on sulphydryl dextran gel,which can enhance the selectivity of the method significantly.
A new method for the determination of trace tin has been established.The method is based on the catalytic effect of Sn(Ⅳ) on the oxidation of 3-(3'-chlorophenyl)-5-(2'-aresenoxylphenylazo)rhodanine by potassium periodate in a buffer solution of potassium hydrogen phthalate-sodium hydroxide at pH=5.0,where the apparent active energy and reaction rate constant are calculated to be 51.20 kJ/mol and 1.23×10-2/s.The excitation and emission wave lengths are 308 nm/410 nm,the linear range is 0~0.01 ×10-6 g/mL,the detection limit is 1.65×1-9 g/mL.The method has been used to determine Sn(Ⅳ) in food and enviro-nmental water with satisfactory results after separation and enrichment on sulphydryl dextran gel,which can enhance the selectivity of the method significantly.
2008, 25(12): 1421-1424
Abstract:
At near room temperature and under ultrasonication,nanocrystalline lanthanum 8-quinolinolate was synthesized by one-step solid-state chemical reaction.The solid phase was characterized by powder X-ray diffraction(XRD) and electron diffraction(ED).The particle size and distribution,and morphology of the prepared nanocrystallites were observed by transmission electron microscopy(TEM).The size of the spherical particles was relatively uniform and the average particle diameter was about 40 nm,and the reaction yield was approximately 95.9%.Furthermore,the reaction conditions,such as reactant type and ratio,presence of inert substance,addition of trace solvent or surfactants,and porphyrization time may influence the morphology,particle size and size distribution of the final product.The process is simple easy to operate,resulting a product of uniform particle size distribution and controllable size with less pollution.Moreover,nanocrystallites of quality can be produced with a high selectivity in high yields and little or no agglomeration normally found in reactions in liquid phase.
At near room temperature and under ultrasonication,nanocrystalline lanthanum 8-quinolinolate was synthesized by one-step solid-state chemical reaction.The solid phase was characterized by powder X-ray diffraction(XRD) and electron diffraction(ED).The particle size and distribution,and morphology of the prepared nanocrystallites were observed by transmission electron microscopy(TEM).The size of the spherical particles was relatively uniform and the average particle diameter was about 40 nm,and the reaction yield was approximately 95.9%.Furthermore,the reaction conditions,such as reactant type and ratio,presence of inert substance,addition of trace solvent or surfactants,and porphyrization time may influence the morphology,particle size and size distribution of the final product.The process is simple easy to operate,resulting a product of uniform particle size distribution and controllable size with less pollution.Moreover,nanocrystallites of quality can be produced with a high selectivity in high yields and little or no agglomeration normally found in reactions in liquid phase.
2008, 25(12): 1425-1429
Abstract:
In the molecule of the natural product botrytinone isolated from the metabolites of marine-derived fungus Botrytis sp.,there are three chiral centers.2D NOE spectrum and quantum chemistry calculation all confirmed that the 7-CH3 and 5-OH are on the same side and the 4-OH on the other side.On the basis of X-ray diffraction analysis,its p-bromobenzoyl derivative C21H15Br2ClO5 belongs to triclinic system with space group P-1,a=0.668 47(5) nm,b=1.218 90(9) nm,c=1.307 8(1) nm,α=83.984(1)°,β=80.366(1)°,γ=84.514(1)°,V=1.041 5(1) nm3,and Z=2,which further support its relative structure.The CD spectrum of its p-bromobenzoyl derivative shows minor Cotton effection at 243 nm(Δε-39.9).The absolute configuration was elucidated by CD exciton chirality method.Finally it was determined to be(4R,5S,6R)-4,5-dihydroxy-3-(1-hydroxyethyl)-2-cyclopenten-1-one.
In the molecule of the natural product botrytinone isolated from the metabolites of marine-derived fungus Botrytis sp.,there are three chiral centers.2D NOE spectrum and quantum chemistry calculation all confirmed that the 7-CH3 and 5-OH are on the same side and the 4-OH on the other side.On the basis of X-ray diffraction analysis,its p-bromobenzoyl derivative C21H15Br2ClO5 belongs to triclinic system with space group P-1,a=0.668 47(5) nm,b=1.218 90(9) nm,c=1.307 8(1) nm,α=83.984(1)°,β=80.366(1)°,γ=84.514(1)°,V=1.041 5(1) nm3,and Z=2,which further support its relative structure.The CD spectrum of its p-bromobenzoyl derivative shows minor Cotton effection at 243 nm(Δε-39.9).The absolute configuration was elucidated by CD exciton chirality method.Finally it was determined to be(4R,5S,6R)-4,5-dihydroxy-3-(1-hydroxyethyl)-2-cyclopenten-1-one.
2008, 25(12): 1430-1434
Abstract:
A spherical cathode material LiNi0.95Al0.05O2 was synthesized by melt-salt coating method in air using LiNO3,Al(NO3)3·9H2O and spherical Ni(OH)2 as starting materials.The morphology,structure and performence of the resulted product were characterized.The effects of synthesizing temperature,time and excess Lithium on the structure and electrochemical property of the resulted products were systemically investigated.The experimental results show that the synthesized material LiNi1-xAlxO2 has the α-NaFeO2 type ordered layered structure,spherical morphology and good electrochemical performance.The optimized conditions to synthesize LiNi0.95Al0.05O2 are to calcine at 750℃ for 16 h with 10% excess lithium in the starting materials.The sample prepared under such conditions has the highest initial discharge capacity of 176 mA·h/g,the smallest irreversible capacity loss of 22.5% and the discharge capacity of LiNi0.95Al0.05O2 still retains at 167.1 mA·h/g and the capacity retention ratio is 94.9% after 30 cycles at a constant current density of 30 mA/g between 2.5 and 4.35 V versus Li at room temperature.
A spherical cathode material LiNi0.95Al0.05O2 was synthesized by melt-salt coating method in air using LiNO3,Al(NO3)3·9H2O and spherical Ni(OH)2 as starting materials.The morphology,structure and performence of the resulted product were characterized.The effects of synthesizing temperature,time and excess Lithium on the structure and electrochemical property of the resulted products were systemically investigated.The experimental results show that the synthesized material LiNi1-xAlxO2 has the α-NaFeO2 type ordered layered structure,spherical morphology and good electrochemical performance.The optimized conditions to synthesize LiNi0.95Al0.05O2 are to calcine at 750℃ for 16 h with 10% excess lithium in the starting materials.The sample prepared under such conditions has the highest initial discharge capacity of 176 mA·h/g,the smallest irreversible capacity loss of 22.5% and the discharge capacity of LiNi0.95Al0.05O2 still retains at 167.1 mA·h/g and the capacity retention ratio is 94.9% after 30 cycles at a constant current density of 30 mA/g between 2.5 and 4.35 V versus Li at room temperature.
2008, 25(12): 1435-1438
Abstract:
The solid content and the molecular mass of the polymer in mixed poly-tetrahydrofuran liquids were determined online by near-infrared spectroscopy(NIR) to explore the real-time monitoring of the polymerization process of tetrahydrofuran.The coefficients(R) of calibration models of the solid content and the molecular mass of the polymer derived by the partial least square method are 0.998 6 and 0.993 6 respectively,root mean square errors of crosss-verification(RMSECV) are 0.455 and 59.7.Based on external verification samples,the model was analyzed by means of t-verification.The results are 0.44 and 1.01,which are under the given significance level at 0.05(t0.05(20)=2.09) condition.Result of the near-infrared spectrum method was compared with that of standard method,and there existed no significance difference.
The solid content and the molecular mass of the polymer in mixed poly-tetrahydrofuran liquids were determined online by near-infrared spectroscopy(NIR) to explore the real-time monitoring of the polymerization process of tetrahydrofuran.The coefficients(R) of calibration models of the solid content and the molecular mass of the polymer derived by the partial least square method are 0.998 6 and 0.993 6 respectively,root mean square errors of crosss-verification(RMSECV) are 0.455 and 59.7.Based on external verification samples,the model was analyzed by means of t-verification.The results are 0.44 and 1.01,which are under the given significance level at 0.05(t0.05(20)=2.09) condition.Result of the near-infrared spectrum method was compared with that of standard method,and there existed no significance difference.
2008, 25(12): 1439-1443
Abstract:
2-(3-Indoly)ethyamine and 2-aminobenzoic acid were used as the starting material and iminoketene was used as the key intermediate to react with 3,4-dihydro-β-carboline or 3,4-dihydroisoquinoline.The reaction afforded rutaecarpine.The reaction is simple and yield is high.Quinazolone compounds can be easily synthesized by the same method with 2-(3,4-diethoxyphenyl)ethylamine as the starting material.The paper thus gives a method for the synthesis of pharmacological active rutaecarpine and quinazolone in industry.The obtained compounds were characterized by ESI-MS,1H NMR,13C NMR.
2-(3-Indoly)ethyamine and 2-aminobenzoic acid were used as the starting material and iminoketene was used as the key intermediate to react with 3,4-dihydro-β-carboline or 3,4-dihydroisoquinoline.The reaction afforded rutaecarpine.The reaction is simple and yield is high.Quinazolone compounds can be easily synthesized by the same method with 2-(3,4-diethoxyphenyl)ethylamine as the starting material.The paper thus gives a method for the synthesis of pharmacological active rutaecarpine and quinazolone in industry.The obtained compounds were characterized by ESI-MS,1H NMR,13C NMR.
2008, 25(12): 1444-1447
Abstract:
A novel,simple and selective method was developed for the determination of promethazine hydrochloride with the resonance light scattering technique.The method was based on the enhancement effect of promethazine hydrochloride on the weak resonance light scattering of eosine B in a pH=3.50 Walpole buffer solution with the maximum light scattering peak at 363 nm.The enhanced RLS intensity was proportional to the concentration of promethazine hydrochloride in a range of 7.5×10-8~4.5×10-6 g/mL with a detection limit of 1.8×10-8 g/mL.This method has been applied successfully to the determination of promethazine hydrochloride in tablets,injection and spiked biological fluid samples.
A novel,simple and selective method was developed for the determination of promethazine hydrochloride with the resonance light scattering technique.The method was based on the enhancement effect of promethazine hydrochloride on the weak resonance light scattering of eosine B in a pH=3.50 Walpole buffer solution with the maximum light scattering peak at 363 nm.The enhanced RLS intensity was proportional to the concentration of promethazine hydrochloride in a range of 7.5×10-8~4.5×10-6 g/mL with a detection limit of 1.8×10-8 g/mL.This method has been applied successfully to the determination of promethazine hydrochloride in tablets,injection and spiked biological fluid samples.
2008, 25(12): 1448-1454
Abstract:
The presented study is focused on the investigation of influence factors and mechanism of small-volume liquid extraction of four amphetamines,named amphetamine(AM),methamphetamine(MAM),3,4-methylenedioxyamphetamine(MDA) and 3,4-methylenemethamphtamine(MDMA) in biological samples.The extraction efficiencies between regular volume and small volume extraction methods were compared;some influence factors for small-volume liquid extraction such as the type and volume of organic solvent,concentration of target analytes in aqueous phase were examined,and the mechanism was studied preliminarily.It was shown that small-volume liquid extraction has a certain effect on the enrichment of analytes,the smaller the volume was,and also the lower the analytes concentration in aqueous solution was,the greater the enrichment gained.It could be deduced that organic film between organic and aqueous phases played an important role in the enrichment.Some biological specimens such as saliva and hair were extracted by means of the method.The organic phase was directly injected into GC for analysis,or transferred into another vial for derivatization after extraction.The LOD for these amphetamines was 5×1-8 g/mL in saliva with GC/MS-SIM without derivatization,and 5×10-11 g/mg in hair after MBTFA derivatization.The method validation data demonstrate that all parameters such as linearity,repeatability,relative standard variation and accuracy can meet the requirement for the drug analysis.The extraction procedure is simple,sensitive,economic and time-saving,and can be used for the analysis of the drugs in biological specimens.
The presented study is focused on the investigation of influence factors and mechanism of small-volume liquid extraction of four amphetamines,named amphetamine(AM),methamphetamine(MAM),3,4-methylenedioxyamphetamine(MDA) and 3,4-methylenemethamphtamine(MDMA) in biological samples.The extraction efficiencies between regular volume and small volume extraction methods were compared;some influence factors for small-volume liquid extraction such as the type and volume of organic solvent,concentration of target analytes in aqueous phase were examined,and the mechanism was studied preliminarily.It was shown that small-volume liquid extraction has a certain effect on the enrichment of analytes,the smaller the volume was,and also the lower the analytes concentration in aqueous solution was,the greater the enrichment gained.It could be deduced that organic film between organic and aqueous phases played an important role in the enrichment.Some biological specimens such as saliva and hair were extracted by means of the method.The organic phase was directly injected into GC for analysis,or transferred into another vial for derivatization after extraction.The LOD for these amphetamines was 5×1-8 g/mL in saliva with GC/MS-SIM without derivatization,and 5×10-11 g/mg in hair after MBTFA derivatization.The method validation data demonstrate that all parameters such as linearity,repeatability,relative standard variation and accuracy can meet the requirement for the drug analysis.The extraction procedure is simple,sensitive,economic and time-saving,and can be used for the analysis of the drugs in biological specimens.
2008, 25(12): 1455-1459
Abstract:
Polyethyleneimine was grafted on silica gel(PEI/SiO2) by a coupling agent,then PEI on silica gel was converted to tertiary amine with epihydrin and quaterisation followed by reaction with benzyl chloride to obtain water-insoluble antibacterial material(QPEI/SiO2).The chemical structures of the products were characterized with FTIR spectroscopy.The degree of grafting was 15.7%,the most highest quaternary degree was 1.57 mmol/g.The antibacterial characteristics and mechanisms of QPEI/SiO2 to E.Coli and S.aureus were tested primarily.The effects of quaternary degrees on the antimicrobial property of QPEI/SiO2 were examined.The experiment results indicate that QPEI/SiO2 has a very strong antimicrobial ability.The antimicrobial ratio to E.Coli reached to 100% and to S.aureus can be closed to 100% when it is contacting with bacterium suspension of 1×109 CFU/mL under the conditions of a dose of 15 g/L.The higher the cationic degree is,the better the antimicrobial activity is.The measured results of enzyme activitiy show that the antimicrobial mechanism of QPEI/SiO2 is based on a sterilizing bacterium process.
Polyethyleneimine was grafted on silica gel(PEI/SiO2) by a coupling agent,then PEI on silica gel was converted to tertiary amine with epihydrin and quaterisation followed by reaction with benzyl chloride to obtain water-insoluble antibacterial material(QPEI/SiO2).The chemical structures of the products were characterized with FTIR spectroscopy.The degree of grafting was 15.7%,the most highest quaternary degree was 1.57 mmol/g.The antibacterial characteristics and mechanisms of QPEI/SiO2 to E.Coli and S.aureus were tested primarily.The effects of quaternary degrees on the antimicrobial property of QPEI/SiO2 were examined.The experiment results indicate that QPEI/SiO2 has a very strong antimicrobial ability.The antimicrobial ratio to E.Coli reached to 100% and to S.aureus can be closed to 100% when it is contacting with bacterium suspension of 1×109 CFU/mL under the conditions of a dose of 15 g/L.The higher the cationic degree is,the better the antimicrobial activity is.The measured results of enzyme activitiy show that the antimicrobial mechanism of QPEI/SiO2 is based on a sterilizing bacterium process.
2008, 25(12): 1460-1463
Abstract:
Two new bis-arylthiosemicarbazone receptors were designed and synthesized.The binding properties of the receptors with anions such as F-,Cl-,Br-,I-,CH3COO-,HSO4-,H2PO4- and NO3- in DMSO were investigated by UV-Vis spectroscopy.A clear color change from colorless to yellow was observed upon addition of NO3-,CH3COO-or H2PO4- to the solution of the two receptors in DMSO by naked-eyes.The results show that the two receptors have a better selectivity forF-,CH3COO-and H2PO4-,but exhibit no evident binding with Cl-,Br-,I-,HSO4- and NO3-.The data show that the two receptors have different binding abilities with the three anions.For the same anion,the association constants show the trend:receptor S1>receptor S2.The UV-Vis data indicate that a 1:1 stoichiometry complex is formed between the receptors and the three anions.Solvation effect confirmed the hydrogen bonding interactions between the receptors and anions.
Two new bis-arylthiosemicarbazone receptors were designed and synthesized.The binding properties of the receptors with anions such as F-,Cl-,Br-,I-,CH3COO-,HSO4-,H2PO4- and NO3- in DMSO were investigated by UV-Vis spectroscopy.A clear color change from colorless to yellow was observed upon addition of NO3-,CH3COO-or H2PO4- to the solution of the two receptors in DMSO by naked-eyes.The results show that the two receptors have a better selectivity forF-,CH3COO-and H2PO4-,but exhibit no evident binding with Cl-,Br-,I-,HSO4- and NO3-.The data show that the two receptors have different binding abilities with the three anions.For the same anion,the association constants show the trend:receptor S1>receptor S2.The UV-Vis data indicate that a 1:1 stoichiometry complex is formed between the receptors and the three anions.Solvation effect confirmed the hydrogen bonding interactions between the receptors and anions.
2008, 25(12): 1464-1467
Abstract:
The carbon nanotube powder microelectrode(CNTPME) was prepared and the electrochemical behaviors of acetaminophen(ACOP) at carbon nanotube powder microelectrode was investigated.The results show that the CNTPME exhibited efficiently catalytic oxidation for ACOP.In 0.08 mol/L BR buffer solution(pH=0.15),the differential pulse voltamogram current was linearly proportional to the concentration of ACOP in a range of 8.8×10-6~1.0×10-4 mol/L and the detection limit was calculated to be 2.64×10-6 mol/L.The CNTPME shows higher sensitivity,stability and longer life compared with chemically modified electrode.Ascorbic acid,which has been shown to be a common interfering compound,had little interference with the determination of ACOP.The results show that the CNTPME can be used for the determination of ACOP in pharmaceutical preparations.
The carbon nanotube powder microelectrode(CNTPME) was prepared and the electrochemical behaviors of acetaminophen(ACOP) at carbon nanotube powder microelectrode was investigated.The results show that the CNTPME exhibited efficiently catalytic oxidation for ACOP.In 0.08 mol/L BR buffer solution(pH=0.15),the differential pulse voltamogram current was linearly proportional to the concentration of ACOP in a range of 8.8×10-6~1.0×10-4 mol/L and the detection limit was calculated to be 2.64×10-6 mol/L.The CNTPME shows higher sensitivity,stability and longer life compared with chemically modified electrode.Ascorbic acid,which has been shown to be a common interfering compound,had little interference with the determination of ACOP.The results show that the CNTPME can be used for the determination of ACOP in pharmaceutical preparations.
2008, 25(12): 1468-1473
Abstract:
p-Nitro-calix[8]arene was synthesized with p-t-butyl-calix[8]arene and paraform as starting materials.The complex characteristics of p-nitro-calix[8]arene and HMX in CHCl3 was studied by UV-visible spectroscopy.The optimized monomers and conformer of p-nitro-calix[8]arene with HMX have been obtained with quantum chemistry half-empirical AM1and ab initio HF/3-21G methods,respectively.The result reveals that the relative quantity ratio is 1:1.The intermolecular interaction energy of the supramolecular complex is 60.76 kJ/mol,indicating that hydrogen bond is formed between p-nitro-calix[8]arene and HMX.In the mean time,the changes of thermodynamic properties from the monomers to supermolecules with the temperature ranged from 288 to 408 K were obtained via the statistical thermodynamics by AM1 method.The stability equilibrium constant Kw of the supramolecular complex is decreased from 1.138×1012 at 288 K to 1.121×105 at 408 K.
p-Nitro-calix[8]arene was synthesized with p-t-butyl-calix[8]arene and paraform as starting materials.The complex characteristics of p-nitro-calix[8]arene and HMX in CHCl3 was studied by UV-visible spectroscopy.The optimized monomers and conformer of p-nitro-calix[8]arene with HMX have been obtained with quantum chemistry half-empirical AM1and ab initio HF/3-21G methods,respectively.The result reveals that the relative quantity ratio is 1:1.The intermolecular interaction energy of the supramolecular complex is 60.76 kJ/mol,indicating that hydrogen bond is formed between p-nitro-calix[8]arene and HMX.In the mean time,the changes of thermodynamic properties from the monomers to supermolecules with the temperature ranged from 288 to 408 K were obtained via the statistical thermodynamics by AM1 method.The stability equilibrium constant Kw of the supramolecular complex is decreased from 1.138×1012 at 288 K to 1.121×105 at 408 K.
2008, 25(12): 1474-1477
Abstract:
Silver nanoparticles in hyperbranched poly(amine-ester)(HPAE) were prepared by means of the reduction of Ag+ with NaBH4 or UV irradiation.HPAE was found to play a key role in the formation of the nanosized particles.Transmission electron microscopic(TEM) analysis showed that silver nanoparticles were spherical and homogeneously dispersed in HPAE with diameters of ~45 nm(NaBH4 reduction) or ~20 nm(UV irradiation).The longer the UV irradiation,the larger the silver nanoparticles' size,and the higher yield.The absorption peaks due to the characteristic surface plasmon resonance of the obtained silver nanoparticles were observed at ~420 nm in the ultraviolet-visible(UV-Vis) absorption spectra.FT-IR spectra confirm that there were strong interactions between silver nanoparticles and HPAE,showing that HPAE provided a very effective protection on silver nanoparticles.
Silver nanoparticles in hyperbranched poly(amine-ester)(HPAE) were prepared by means of the reduction of Ag+ with NaBH4 or UV irradiation.HPAE was found to play a key role in the formation of the nanosized particles.Transmission electron microscopic(TEM) analysis showed that silver nanoparticles were spherical and homogeneously dispersed in HPAE with diameters of ~45 nm(NaBH4 reduction) or ~20 nm(UV irradiation).The longer the UV irradiation,the larger the silver nanoparticles' size,and the higher yield.The absorption peaks due to the characteristic surface plasmon resonance of the obtained silver nanoparticles were observed at ~420 nm in the ultraviolet-visible(UV-Vis) absorption spectra.FT-IR spectra confirm that there were strong interactions between silver nanoparticles and HPAE,showing that HPAE provided a very effective protection on silver nanoparticles.
2008, 25(12): 1478-1483
Abstract:
The pyrolysis behavior of hemp pulp cigarette paper was investigated via thermal gravimetric analysis(TGA) and pyrolysis gas chromatography-mass spectrometry(PyGC/MS).In helium atmosphere,the compound was pyrolyzed at 400,500,600,700,800,and 900℃,respective.y.The pyrolysis products were directly introduced into GC/MS with 1.03×106 Pa He and were qualitatively and semi-quantitatively analyzed.The results show that different pyrolysis temperatures directly impact on the type of and relative contents the pyrolysis products.At the seven pyrolysis temperatures mentioned above,complex pyrolysis products were formed and 156 products were detected altogether,including 1-methyl-1,3-cyclopentadiene,2-methylfuran,2,3-dihydrobenzofuran,benzene,and toluene.Moreover,at low temperatures,the main pyrolysis products were alkenes,furans,and ketones.With the elevation of the pyrolysis temperature,the contents of alkenes and ketones decreased,and the contents of benzene,benzene derivatives,and PAHs(polycyclic aromatic hydrocarbons) increased gradually.The contents of harmful pyrolysis products of the cigarette paper can be reduced by reducing the cigarette combustion temperature.If only the impact of hemp pulp cigarette paper is considered,the best combustion temperature of cigarette should be controlled at 500℃.
The pyrolysis behavior of hemp pulp cigarette paper was investigated via thermal gravimetric analysis(TGA) and pyrolysis gas chromatography-mass spectrometry(PyGC/MS).In helium atmosphere,the compound was pyrolyzed at 400,500,600,700,800,and 900℃,respective.y.The pyrolysis products were directly introduced into GC/MS with 1.03×106 Pa He and were qualitatively and semi-quantitatively analyzed.The results show that different pyrolysis temperatures directly impact on the type of and relative contents the pyrolysis products.At the seven pyrolysis temperatures mentioned above,complex pyrolysis products were formed and 156 products were detected altogether,including 1-methyl-1,3-cyclopentadiene,2-methylfuran,2,3-dihydrobenzofuran,benzene,and toluene.Moreover,at low temperatures,the main pyrolysis products were alkenes,furans,and ketones.With the elevation of the pyrolysis temperature,the contents of alkenes and ketones decreased,and the contents of benzene,benzene derivatives,and PAHs(polycyclic aromatic hydrocarbons) increased gradually.The contents of harmful pyrolysis products of the cigarette paper can be reduced by reducing the cigarette combustion temperature.If only the impact of hemp pulp cigarette paper is considered,the best combustion temperature of cigarette should be controlled at 500℃.
2008, 25(12): 1484-1486
Abstract:
CdS nanoparticles were synthesized in water solution,the surface of CdS nanoparticles was modified with poly-4-pentenoic acid under ultrasonic irradiation.With CdS/PPA nanoparticle solution as fluorescence probe combined with synchronous fluorescence spectrometry,a method for determination of BSA in water solution was developed.The working curve for determination of BSA is ΔF=117.50+29.55c(1×10-6 g/mL),the linear range is 0.5×10-6~30×10-6 g/mL,the limit of detection is 0.12×10-6 g/mL.In addition,the present method was applied to quantifying BSA in synthetic samples.
CdS nanoparticles were synthesized in water solution,the surface of CdS nanoparticles was modified with poly-4-pentenoic acid under ultrasonic irradiation.With CdS/PPA nanoparticle solution as fluorescence probe combined with synchronous fluorescence spectrometry,a method for determination of BSA in water solution was developed.The working curve for determination of BSA is ΔF=117.50+29.55c(1×10-6 g/mL),the linear range is 0.5×10-6~30×10-6 g/mL,the limit of detection is 0.12×10-6 g/mL.In addition,the present method was applied to quantifying BSA in synthetic samples.
2008, 25(12): 1487-1489
Abstract:
Six stilbene derivatives were synthesized by Heck reaction with yields of 68%~84%.The influence of the reactant structure on the yield of the Heck reaction was investigated.The optimal results were obtained at 120℃ reaction temperature with a DMF and Et3N mixture(2:1,V/V) as the solvent.It was also found that the yield decreased with decrease of the electron density on the double bond of the molecule(4-methylstyrene >styrene >4-vinyl pyridine);the reactivity of the halogen was in the order of NO2-Ar-Br >H-Ar-Br >CH3-Ar-Brr.
Six stilbene derivatives were synthesized by Heck reaction with yields of 68%~84%.The influence of the reactant structure on the yield of the Heck reaction was investigated.The optimal results were obtained at 120℃ reaction temperature with a DMF and Et3N mixture(2:1,V/V) as the solvent.It was also found that the yield decreased with decrease of the electron density on the double bond of the molecule(4-methylstyrene >styrene >4-vinyl pyridine);the reactivity of the halogen was in the order of NO2-Ar-Br >H-Ar-Br >CH3-Ar-Brr.
2008, 25(12): 1490-1492
Abstract:
A polarimetry method was developed for the determination of S-2-(aminomethyl)-1-ethylpyrrolidine.At(20±0.5)℃,the optical rotation of S-2-(aminomethyl)-1-ethylpyrrolidine was determined with ethanol as the solvent at 589.3 nm wavelength.In the concentration range of 0.02~0.05 g/mL,the following linear regression equation,a=-0.936 9c-0.031 1(r=1.000),was established,and the average recovery was 99.84%,and the RSD was 0.23%(n=4).The method is accurate,simple,fast,stable and credible,and it can be used for the quality control of S-2-(aminomethyl)-1-ethylpy-rrolidine.
A polarimetry method was developed for the determination of S-2-(aminomethyl)-1-ethylpyrrolidine.At(20±0.5)℃,the optical rotation of S-2-(aminomethyl)-1-ethylpyrrolidine was determined with ethanol as the solvent at 589.3 nm wavelength.In the concentration range of 0.02~0.05 g/mL,the following linear regression equation,a=-0.936 9c-0.031 1(r=1.000),was established,and the average recovery was 99.84%,and the RSD was 0.23%(n=4).The method is accurate,simple,fast,stable and credible,and it can be used for the quality control of S-2-(aminomethyl)-1-ethylpy-rrolidine.
2008, 25(12): 1493-1495
Abstract:
Sn complex Sn(OCH2CH2O)2 was directly synthesized in HOCH2CH2OH solution in 50 mL flask.The nano-SnO2 powder was prepared by a direct sol-gel of the above solution followed by dryness at 350℃ for 2 h.The product Sn(OCH2CH2O)2 was characterized by FT-IR,Raman and NMR.XRD,and TEM were used to investigate the structure of nano-SnO2.The experiments show Sn(OCH2CH2O)2 contained-OCH2CH2O-group and could prevent the precursor from aggregating during the process of hydrolysis and calcination.The nano-SnO2 with a diameter of 10~30 nm was thus obtained in a high purity.
Sn complex Sn(OCH2CH2O)2 was directly synthesized in HOCH2CH2OH solution in 50 mL flask.The nano-SnO2 powder was prepared by a direct sol-gel of the above solution followed by dryness at 350℃ for 2 h.The product Sn(OCH2CH2O)2 was characterized by FT-IR,Raman and NMR.XRD,and TEM were used to investigate the structure of nano-SnO2.The experiments show Sn(OCH2CH2O)2 contained-OCH2CH2O-group and could prevent the precursor from aggregating during the process of hydrolysis and calcination.The nano-SnO2 with a diameter of 10~30 nm was thus obtained in a high purity.
2008, 25(12): 1496-1498
Abstract:
Alkali-soluble tea polysaccharides(ATPS) were extracted from tea residue after decocting of low-grade green tea.There were 3 kinds of homogeneous constituents whose mass fractions were about 5.96%,78.99% and 15.05%(according to the retention time) analyzed by means of HPGPC-ELSD in ATPS.The polysaccharides were made up of six kinds of monosaccharide residues(rhamnose,arabinose,xylose,mannose,glucose and galatose) determined by means of GC-MS as well as their molar ratio.CD spectra of ATPS in water showed a positive Cotton effect at 190 nm and negative Cotton effect at 203 nm.
Alkali-soluble tea polysaccharides(ATPS) were extracted from tea residue after decocting of low-grade green tea.There were 3 kinds of homogeneous constituents whose mass fractions were about 5.96%,78.99% and 15.05%(according to the retention time) analyzed by means of HPGPC-ELSD in ATPS.The polysaccharides were made up of six kinds of monosaccharide residues(rhamnose,arabinose,xylose,mannose,glucose and galatose) determined by means of GC-MS as well as their molar ratio.CD spectra of ATPS in water showed a positive Cotton effect at 190 nm and negative Cotton effect at 203 nm.
2008, 25(12): 1499-1501
Abstract:
Composite coatings of Ni-nanoAl2O3 were obtained by direct current(DC),pulse current(PC) and pulse reverse current(PRC) electro deposition techniques.The effects of different coating methods on the structure of the composite coating were studied and the cross-section morphology and microstructure of the Ni-nano Al2O3 were analyzed by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and XRD.Corrosion resistance of the coating to 3.5% NaCl solution was performed.The result showed that the prep method can significantly affect the coating microstructure and matrix grain size.The minimum size of the metal matrix Ni grains in the composition coating obtained by PRC deposition was approximately 24 nm,while the maximum grain size of Ni obtained by DC was about 38 nm.Polarization test indicated that the corrosion resistance of the composite coating Ni-nano Al2O3 deposited by PRC was the optimal one,while that by DC was the worst.The corrosion current and corrosion voltage were 2.8×10-7 A and-0.225 V for composite coating Ni-nanoAl2O3 deposited by PRC,and 3.16×10-6 A and-0.328 V for that deposited by the latter,respectively.
Composite coatings of Ni-nanoAl2O3 were obtained by direct current(DC),pulse current(PC) and pulse reverse current(PRC) electro deposition techniques.The effects of different coating methods on the structure of the composite coating were studied and the cross-section morphology and microstructure of the Ni-nano Al2O3 were analyzed by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and XRD.Corrosion resistance of the coating to 3.5% NaCl solution was performed.The result showed that the prep method can significantly affect the coating microstructure and matrix grain size.The minimum size of the metal matrix Ni grains in the composition coating obtained by PRC deposition was approximately 24 nm,while the maximum grain size of Ni obtained by DC was about 38 nm.Polarization test indicated that the corrosion resistance of the composite coating Ni-nano Al2O3 deposited by PRC was the optimal one,while that by DC was the worst.The corrosion current and corrosion voltage were 2.8×10-7 A and-0.225 V for composite coating Ni-nanoAl2O3 deposited by PRC,and 3.16×10-6 A and-0.328 V for that deposited by the latter,respectively.
2008, 25(12): 1502-1504
Abstract:
Isosorbide-5-mononitrate is a new long-lasting nitrate medicine for angina pectoris.Ionic liquid was used in the synthesis of the intermediate of isosorbide-5-mononitrate.Isosorbide was purified by extraction of the crude product with ionic liquid 1-butyl-3-methyl imidazole hexafluorophosphate instead of high vacuum distillation.Isosorbide-2-monoacetate was then synthesized by reacting the purified isosorbide with acetic anhydride in acidic ionic liquid N-methylimidazole hydrosulfate.The structures of products were characterized by means of IR techniques.The yields of isosorbide and isosorbide-2-monoacetate were 80% and 86% respectively.
Isosorbide-5-mononitrate is a new long-lasting nitrate medicine for angina pectoris.Ionic liquid was used in the synthesis of the intermediate of isosorbide-5-mononitrate.Isosorbide was purified by extraction of the crude product with ionic liquid 1-butyl-3-methyl imidazole hexafluorophosphate instead of high vacuum distillation.Isosorbide-2-monoacetate was then synthesized by reacting the purified isosorbide with acetic anhydride in acidic ionic liquid N-methylimidazole hydrosulfate.The structures of products were characterized by means of IR techniques.The yields of isosorbide and isosorbide-2-monoacetate were 80% and 86% respectively.
