The impact properties of normal concrete (NC) and reinforced concrete (RC) specimens,steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the...The impact properties of normal concrete (NC) and reinforced concrete (RC) specimens,steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the drop-weight impact test recommended by ACI Committee 544.The results indicate that the number of blows to final failure is greatly increased by addition of steel fibres.Moreover,the combination of steel fibres and steel rebars demonstrates a significant positive composite effect on the impact resistance,which results in the improvement in impact toughness of concrete specimens.In the view of variation of impact test results,the two-parameter Weibull distribution was adopted to analyze the experimental data.It is proved that the probabilistic distributions of the blows to first crack and to final failure of six types of samples approximately follow two-parameter Weibull distribution.展开更多
The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concent...The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concentration of hydroxypropyl-β-cyclodextrin(HP-β-CD),percentage of organic modifier,pH value and column temperature on enantioselective separation were investigated.The quantification property of the developed RP-HPLC method was examined.The chiral recognition mechanism of PSA was also discussed.The results show that a baseline separation of PSA enantiomers is achieved on a Lichrospher C18 column(4.6 mm(inner diameter)×250 mm,5μm)with HP-β-CD as chiral mobile phase additive.The capacity factors of R-PSA and S-PSA are 3.94 and 4.80,respectively.The separation factor and resolution are respectively 1.22 and 8.03.The mobile phase is a mixture of acetonitrile and deionized water(20-80,volume ratio)containing 10 mmol/L HP-β-CD and 0.05% trifluoroacetic acid(pH 2.5,adjusted with triethylamine)with a flow rate of 1.0 mL/min.The ultraviolet(UV)detector is set at 254 nm.The likely roles are inclusion interaction,induction and hydrogen bonding between HP-β-CD and PSA enantiomers.展开更多
The method of reversed-phase high performance liquid chromatography was established for the determination of effective components in OC-CS spray using double wavelength UV detection.The method was utilized under follo...The method of reversed-phase high performance liquid chromatography was established for the determination of effective components in OC-CS spray using double wavelength UV detection.The method was utilized under following conditions:a column of Kromasil C18(250 mm × 4.6 mm,5 μm),mobile phase consisting of methanol/water(80 /20) at a flow rate of 0.8 mL/min,column temperature of 25 ℃,and the UV detection at 227 nm and 300 nm.Three key components in OC-CS spray could be distinguished clearly,including o-chlorobenzalmalononitrile(CS),oleoresin capsicum(OC) and dihydrocapsaicin(DC).This method has the advantages of fast,simple and satisfactory linear relationship between UV absorption and concentration.It may be considered to turn into a standard method for detection of related components in the spray.展开更多
High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode e...High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.展开更多
Aqueous zinc metal batteries(ZMBs)which are environmentally benign and cheap can be used for grid-scale energy storage,but have a short cycling life mainly due to the poor reversibility of zinc metal anodes in mild aq...Aqueous zinc metal batteries(ZMBs)which are environmentally benign and cheap can be used for grid-scale energy storage,but have a short cycling life mainly due to the poor reversibility of zinc metal anodes in mild aqueous electrolytes.A zincophilic carbon(ZC)layer was deposited on a Zn metal foil at 450°C by the up-stream pyrolysis of a hydrogen-bonded supramolecular substance framework,as-sembled from melamine(ME)and cyanuric acid(CA).The zincophilic groups(C=O and C=N)in the ZC layer guide uniform zinc plating/stripping and eliminate dendrites and side reactions.so that assembled symmetrical batteries(ZC@Zn//ZC@Zn)have a long-term service life of 2500 h at 1 mA cm^(−2) and 1 mAh cm^(−2),which is much longer than that of bare Zn anodes(180 h).In addition,ZC@Zn//V2O5 full batteries have a higher capacity of 174 mAh g^(−1) after 1200 cycles at 2 A g^(−1) than a Zn//V_(2)O_(5) counterpart(100 mAh g^(−1)).The strategy developed for the low-temperat-ure deposition of the ZC layer is a new way to construct advanced zinc metal anodes for ZMBs.展开更多
The semiclassical transport equations are used to study the high frequency performance of AlGaAs / GaAs HBTs. Electron velocity overshoot effect and its influence on the cut off frequency characteristics of AlGaAs / G...The semiclassical transport equations are used to study the high frequency performance of AlGaAs / GaAs HBTs. Electron velocity overshoot effect and its influence on the cut off frequency characteristics of AlGaAs / GaAs HBTs with different collector design parameters are analyzed and discussed.展开更多
A simple, sensitive and reproducible high performance liquid chromatography-mass spectrometry coupled with electrospray ionization method for simultaneous separation and determination of adenine, adenosine and （urid...A simple, sensitive and reproducible high performance liquid chromatography-mass spectrometry coupled with electrospray ionization method for simultaneous separation and determination of adenine, adenosine and （uridine） was developed. The analytical column is a 2.0 mm×150 mm Shimadzu VP-ODS column and volume fraction of the mobile phase is （86.5%）water, 12.0%methanol and 1.5%formic acid. 2-chloroadenosine was used as internal standard. Selective ion monitoring mode and selective ion monitoring ions at ratio of mass to electric charge of 136 for adenine, 268 for adenosine and 267 for uridine were chosen for quantitative analysis of the three active components. The results show that the regression equations and linear range are Y=0.062X+（0.005） and 2.0140.0 (μg·mL-1)for adenine, Y=0.049X+0.004 and 4.0115.0 μg·mL-1 for uridine, （Y=0.154X）+0.014 and （1.0125.0） μg·mL-1 for adenosine. The limits of detection are 0.6 μg·mL-1 for adenine, 1.0 μg·mL-1for uridine and (0.2 μg·mL-1) for adenosine. The recoveries of the three constituents are from 96.6% to 103.2%.展开更多
Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for t...Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35℃ and 1.0 mL/min, respectively. Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.展开更多
Solidified floating organic drop microextraction(SFODME)in combination with high performance liquid chromatography was used for separation/preconcentration and determination of carbamazepine(CBZ)in human plasma and ur...Solidified floating organic drop microextraction(SFODME)in combination with high performance liquid chromatography was used for separation/preconcentration and determination of carbamazepine(CBZ)in human plasma and urine samples.Parameters that affect the extraction efficiency such as the type and volume of extraction solvent,ionic strength,sodium hydroxide concentration,stirring rate,sample volume and extraction time,were investigated and optimized.Under the optimum conditions(extraction solvent,40μL of 1-undecanol;sodium hydroxide concentration,1 mol/L;temperature,50℃;stirring speed,400 r/min;sample volume,8 mL;sodium chloride concentration,3%(w/v)and extraction time,60 min)the calibration curve was found to be linear in the mass concentration range of 0.4-700.0μg/L.The limit of detection(LOD)was 0.1μg/L and the relative standard deviation(RSD)for six replicate extraction and determination of carbamazepine at 100μg/L level was found to be 4.1%.The method was successfully applied to the determination of CBZ in human plasma and urine samples.展开更多
Tadalafil(TAD)and dapoxetine HCl(DAP)are recently co-formulated and both show native fluorescence.Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chromatographic method with fl...Tadalafil(TAD)and dapoxetine HCl(DAP)are recently co-formulated and both show native fluorescence.Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chromatographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard(IS).Separation was achieved using isocratic elution within 7.0 min on C18column and acetonitrile-0.15%triethylamine(40∶60,v/v;pH 4)as a mobile phase.The flow rate was 1.0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm.The linear ranges from 0.01 to 30.00μg/mL for each drug with the limits of detection of 4.20 and 7.20 ng/mL for TAD and DAP,respectively.The method was validated in accordance to the International Conference on Harmonization(ICH)guidelines and was successfully applied to spiked human plasma with mean recoveries of 98.17%and 98.83%for TAD and DAP respectively.展开更多
Column packings continue to evolve as the needs of users for high efficiency,high resolution and highly sensitive high performance liquid chromatographic(HPLC) analysis drive further developments.In comparing and cont...Column packings continue to evolve as the needs of users for high efficiency,high resolution and highly sensitive high performance liquid chromatographic(HPLC) analysis drive further developments.In comparing and contrasting modern HPLC columns technologies,diameters of column packings and particle materials are covered.Some products and applications of modern HPLC columns are provided.Future directions in packing developments are predicted in this introductory article.展开更多
Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separate...Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separated with high performance liquid chromatography(HPLC) at detection wavelength of 320nm was considered as detection index, two factors of solvent concentration and extraction time were mainly studied at extraction temperature of 85℃ and a volume ratio of solvent to sample of 10∶1. Optimal subclass, quadric polynomial step by step aggression and neural network method were applied to process the experimental results. The results show that the first and second methods give the same factors combination (concentration of ethanol: 95%, extraction time: 3.6 h) and the second method is much better than the first one. The extraction model is consequently developed.展开更多
A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate,a synthetic inorganic ion exchanger as adsorbent in thi...A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate,a synthetic inorganic ion exchanger as adsorbent in thin layer chromatography(TLC).A mixture of methanol and 0.1 mol/L formic acid(3∶7,v/v)was employed as the mobile phase.The development time was 32 min.The quantitative measurement were performed with a Camag TLC Scanner-3 at wavelength(λ)of 410 nm.The isoproterenol recovery in this procedure was 98.9%.The linear correlation coefficient was greater than 0.987 1 and the relative standard deviation(RSD)was less than 0.94.The limit of detection(LOD)and limit of quantification(LOQ)were 7.7×10-7mol/L and 3.85×10-6mol/L,respectively.This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.展开更多
Paclitaxel in southern yew tree was quantitatively determined by high performance liquid chromatography (HPLC) with ODS-C18 column. A mixture of CH3OH-H2O-CH3COOH(volume ratio: 55 :44 :1) is used as mobile phase and U...Paclitaxel in southern yew tree was quantitatively determined by high performance liquid chromatography (HPLC) with ODS-C18 column. A mixture of CH3OH-H2O-CH3COOH(volume ratio: 55 :44 :1) is used as mobile phase and UV detection is carried out at 227 nm, and the column temperature is 20℃. The results show that there is a good linear felationship between the area of paclitaxel and the concentration of the sample in the range 50-500 mg/L for paclitaxel. The corresponding regression equation is Y= 13 021. 7 + 1. 01 × 106X, r=0. 9990. The average recovery is 95. 3% and the relative standard deviation is 2. 08%.展开更多
基金Project(50578026) supported by the National Natural Science Foundation of ChinaProject supported by FCT (SFRH/BPD/22680/2005)and Research Center of Mathematics of the University of Minho through the FCT Pluriannual Funding Program
文摘The impact properties of normal concrete (NC) and reinforced concrete (RC) specimens,steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the drop-weight impact test recommended by ACI Committee 544.The results indicate that the number of blows to final failure is greatly increased by addition of steel fibres.Moreover,the combination of steel fibres and steel rebars demonstrates a significant positive composite effect on the impact resistance,which results in the improvement in impact toughness of concrete specimens.In the view of variation of impact test results,the two-parameter Weibull distribution was adopted to analyze the experimental data.It is proved that the probabilistic distributions of the blows to first crack and to final failure of six types of samples approximately follow two-parameter Weibull distribution.
基金Project(20776038)supported by the National Natural Science Foundation of China
文摘The chiral separation of phenylsuccinic acid(PSA)was studied by reversed phase high-performance liquid chromatography(RP-HPLC)with cyclodextrins(CDs)as chiral mobile phase additives.The effects of types of CDs,concentration of hydroxypropyl-β-cyclodextrin(HP-β-CD),percentage of organic modifier,pH value and column temperature on enantioselective separation were investigated.The quantification property of the developed RP-HPLC method was examined.The chiral recognition mechanism of PSA was also discussed.The results show that a baseline separation of PSA enantiomers is achieved on a Lichrospher C18 column(4.6 mm(inner diameter)×250 mm,5μm)with HP-β-CD as chiral mobile phase additive.The capacity factors of R-PSA and S-PSA are 3.94 and 4.80,respectively.The separation factor and resolution are respectively 1.22 and 8.03.The mobile phase is a mixture of acetonitrile and deionized water(20-80,volume ratio)containing 10 mmol/L HP-β-CD and 0.05% trifluoroacetic acid(pH 2.5,adjusted with triethylamine)with a flow rate of 1.0 mL/min.The ultraviolet(UV)detector is set at 254 nm.The likely roles are inclusion interaction,induction and hydrogen bonding between HP-β-CD and PSA enantiomers.
基金Sponsored by the Basic Research Funds of Beijing Institute of Technology (20081642007)
文摘The method of reversed-phase high performance liquid chromatography was established for the determination of effective components in OC-CS spray using double wavelength UV detection.The method was utilized under following conditions:a column of Kromasil C18(250 mm × 4.6 mm,5 μm),mobile phase consisting of methanol/water(80 /20) at a flow rate of 0.8 mL/min,column temperature of 25 ℃,and the UV detection at 227 nm and 300 nm.Three key components in OC-CS spray could be distinguished clearly,including o-chlorobenzalmalononitrile(CS),oleoresin capsicum(OC) and dihydrocapsaicin(DC).This method has the advantages of fast,simple and satisfactory linear relationship between UV absorption and concentration.It may be considered to turn into a standard method for detection of related components in the spray.
基金Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by CAST,ChinaProject(51932011)supported by the National Natural Science Foundation of China+1 种基金Project(2023JJ10060)supported by the Natural Science Foundation of Hunan Province,ChinaProject(23A0003)supported by the Scientific Research Fund of Hunan Provincial Education Department,China。
文摘High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.
基金partially supported by the National Natural Science Foundation of China(22479022)Liaoning Revitalization Talents Program(XLYC2007129)。
文摘Aqueous zinc metal batteries(ZMBs)which are environmentally benign and cheap can be used for grid-scale energy storage,but have a short cycling life mainly due to the poor reversibility of zinc metal anodes in mild aqueous electrolytes.A zincophilic carbon(ZC)layer was deposited on a Zn metal foil at 450°C by the up-stream pyrolysis of a hydrogen-bonded supramolecular substance framework,as-sembled from melamine(ME)and cyanuric acid(CA).The zincophilic groups(C=O and C=N)in the ZC layer guide uniform zinc plating/stripping and eliminate dendrites and side reactions.so that assembled symmetrical batteries(ZC@Zn//ZC@Zn)have a long-term service life of 2500 h at 1 mA cm^(−2) and 1 mAh cm^(−2),which is much longer than that of bare Zn anodes(180 h).In addition,ZC@Zn//V2O5 full batteries have a higher capacity of 174 mAh g^(−1) after 1200 cycles at 2 A g^(−1) than a Zn//V_(2)O_(5) counterpart(100 mAh g^(−1)).The strategy developed for the low-temperat-ure deposition of the ZC layer is a new way to construct advanced zinc metal anodes for ZMBs.
文摘The semiclassical transport equations are used to study the high frequency performance of AlGaAs / GaAs HBTs. Electron velocity overshoot effect and its influence on the cut off frequency characteristics of AlGaAs / GaAs HBTs with different collector design parameters are analyzed and discussed.
文摘A simple, sensitive and reproducible high performance liquid chromatography-mass spectrometry coupled with electrospray ionization method for simultaneous separation and determination of adenine, adenosine and （uridine） was developed. The analytical column is a 2.0 mm×150 mm Shimadzu VP-ODS column and volume fraction of the mobile phase is （86.5%）water, 12.0%methanol and 1.5%formic acid. 2-chloroadenosine was used as internal standard. Selective ion monitoring mode and selective ion monitoring ions at ratio of mass to electric charge of 136 for adenine, 268 for adenosine and 267 for uridine were chosen for quantitative analysis of the three active components. The results show that the regression equations and linear range are Y=0.062X+（0.005） and 2.0140.0 (μg·mL-1)for adenine, Y=0.049X+0.004 and 4.0115.0 μg·mL-1 for uridine, （Y=0.154X）+0.014 and （1.0125.0） μg·mL-1 for adenosine. The limits of detection are 0.6 μg·mL-1 for adenine, 1.0 μg·mL-1for uridine and (0.2 μg·mL-1) for adenosine. The recoveries of the three constituents are from 96.6% to 103.2%.
基金Project(20235010) support by the NSFC-KOSEF Scientific Cooperation ProgramProject supported by the Program for New Century Talents of University in Henan ProvinceProgram for Backbone Teacher in Henan Province, China
文摘Development of effective chromatographic or electrophoretic separation involves judicious deciding of selection of optimal experimental conditions that can provide an adequate resolution at a reasonable run time for the separation of interested components. Box-Behnken factorial design was effectively applied for the separation optimization of eight structurally related sulfonamides using capillary zone electrophorosis and reverse high performance liquid chromatography. Optimum values for volume ratio of THF to H2O in eluent, column temperature and flow rate of eluent are found as 12 to 88, 35℃ and 1.0 mL/min, respectively. Box-Behnken modified optimization model is extended to separation by capillary electrophoresis (CE). While using CE, a satisfactory separation is achieved with a minimum resolution larger than 1.0 for a separation time less than 10 min.
文摘Solidified floating organic drop microextraction(SFODME)in combination with high performance liquid chromatography was used for separation/preconcentration and determination of carbamazepine(CBZ)in human plasma and urine samples.Parameters that affect the extraction efficiency such as the type and volume of extraction solvent,ionic strength,sodium hydroxide concentration,stirring rate,sample volume and extraction time,were investigated and optimized.Under the optimum conditions(extraction solvent,40μL of 1-undecanol;sodium hydroxide concentration,1 mol/L;temperature,50℃;stirring speed,400 r/min;sample volume,8 mL;sodium chloride concentration,3%(w/v)and extraction time,60 min)the calibration curve was found to be linear in the mass concentration range of 0.4-700.0μg/L.The limit of detection(LOD)was 0.1μg/L and the relative standard deviation(RSD)for six replicate extraction and determination of carbamazepine at 100μg/L level was found to be 4.1%.The method was successfully applied to the determination of CBZ in human plasma and urine samples.
文摘Tadalafil(TAD)and dapoxetine HCl(DAP)are recently co-formulated and both show native fluorescence.Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chromatographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard(IS).Separation was achieved using isocratic elution within 7.0 min on C18column and acetonitrile-0.15%triethylamine(40∶60,v/v;pH 4)as a mobile phase.The flow rate was 1.0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm.The linear ranges from 0.01 to 30.00μg/mL for each drug with the limits of detection of 4.20 and 7.20 ng/mL for TAD and DAP,respectively.The method was validated in accordance to the International Conference on Harmonization(ICH)guidelines and was successfully applied to spiked human plasma with mean recoveries of 98.17%and 98.83%for TAD and DAP respectively.
文摘Column packings continue to evolve as the needs of users for high efficiency,high resolution and highly sensitive high performance liquid chromatographic(HPLC) analysis drive further developments.In comparing and contrasting modern HPLC columns technologies,diameters of column packings and particle materials are covered.Some products and applications of modern HPLC columns are provided.Future directions in packing developments are predicted in this introductory article.
基金Project(2004714) supported by the Development and Innovation Committee of Hunan Province
文摘Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separated with high performance liquid chromatography(HPLC) at detection wavelength of 320nm was considered as detection index, two factors of solvent concentration and extraction time were mainly studied at extraction temperature of 85℃ and a volume ratio of solvent to sample of 10∶1. Optimal subclass, quadric polynomial step by step aggression and neural network method were applied to process the experimental results. The results show that the first and second methods give the same factors combination (concentration of ethanol: 95%, extraction time: 3.6 h) and the second method is much better than the first one. The extraction model is consequently developed.
基金Financial assistance was provided by Kharazmi University,Research Council
文摘A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate,a synthetic inorganic ion exchanger as adsorbent in thin layer chromatography(TLC).A mixture of methanol and 0.1 mol/L formic acid(3∶7,v/v)was employed as the mobile phase.The development time was 32 min.The quantitative measurement were performed with a Camag TLC Scanner-3 at wavelength(λ)of 410 nm.The isoproterenol recovery in this procedure was 98.9%.The linear correlation coefficient was greater than 0.987 1 and the relative standard deviation(RSD)was less than 0.94.The limit of detection(LOD)and limit of quantification(LOQ)were 7.7×10-7mol/L and 3.85×10-6mol/L,respectively.This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.
基金Project (00KNY1010 ) supported by the Key Program of Science and Technology Office of Hunan Province
文摘Paclitaxel in southern yew tree was quantitatively determined by high performance liquid chromatography (HPLC) with ODS-C18 column. A mixture of CH3OH-H2O-CH3COOH(volume ratio: 55 :44 :1) is used as mobile phase and UV detection is carried out at 227 nm, and the column temperature is 20℃. The results show that there is a good linear felationship between the area of paclitaxel and the concentration of the sample in the range 50-500 mg/L for paclitaxel. The corresponding regression equation is Y= 13 021. 7 + 1. 01 × 106X, r=0. 9990. The average recovery is 95. 3% and the relative standard deviation is 2. 08%.
