In this study, a novel and simple high performance liquid chromatography with diode array detection （HPLC-DAD） method for the simultaneous qualitative and quantitative determination of 12 bioactive components in Geg...In this study, a novel and simple high performance liquid chromatography with diode array detection （HPLC-DAD） method for the simultaneous qualitative and quantitative determination of 12 bioactive components in Gegen Qinlian pill was developed. The separation was performed on a Kromasil C18 column （250 mm×4.6 ram, 5.0 μm） by gradient elution with acetonitrile and 0.02 mol/L ammonium acetate （containing 0.3% triethylamine, and adjusted pH to 4.3 using 1% glacial acetic acid） as the mobile phase at a flow rate of 0.7 mL/min. Three different detection wavelengths （250, 280, 346 nm） were set at the maximum UV absorption wavelengths of these components. Twelve components （puerarin, daidzin, baicalin, wogonoside, liquiritin, berberine, palmatine, jatrorrhizine, glycyrrhizin, baicalein, wogonin and daidzein） were identified and determined using the developed method. All calibration curves showed good linear regression （r〉0.9995） within tested ranges. The injection precision, intra-day precisions and analysis repeatability were evaluated with the RSD values, which were no more than 0.97%, 1.69% and 1.71%, respectively. The recoveries were ranged from 97.4% to 100.2% with RSD values less than 1.87%. This readily available, low-cost and reliable HPLC-DAD method would improve the quality control of Gegen Qinlian pill.展开更多
Flooding an extremely alkaline(pH 10.6) saline soil of the former Lake Texcoco to reduce salinity will affect the soil carbon(C)and nitrogen(N) dynamics.A laboratory incubation experiment was done to investigate how d...Flooding an extremely alkaline(pH 10.6) saline soil of the former Lake Texcoco to reduce salinity will affect the soil carbon(C)and nitrogen(N) dynamics.A laboratory incubation experiment was done to investigate how decreasing soil salt content affected dynamics of C and N in an extremely alkaline saline soil.Sieved soil with electrical conductivity(EC) of 59.2 dS m^(-1) was packed in columns,and then flooded with tap water,drained freely and conditioned aerobically at 50%water holding capacity for a month.This process of flooding-drainage-conditioning was repeated eight times.The original soil and the soil that had undergone one,two,four and eight flooding-drainage-conditioning cycles were amended with 1000 mg glucose-^(14)C kg^(-1) soil and 200 mg NH_4^+-N kg^(-1)soil,and then incubated for 28 d.The CO_2 emissions,soil microbial biomass,and soil ammonium(NE_4^+),nitrite(NO_2^-) and nitrate(NO_3^-) were monitored in the aerobic incubation of 28 d.The soil EC decreased from 59.2 to 1.0 dS m^(_1) after eight floodings,and soil pH decreased from 10.6 to 9.6.Of the added ^(14)C-labelled glucose,only 8%was mineralized in the original soil,while 24%in the soil flooded eight times during the 28-d incubation.The priming effect was on average 278 mg C kg^(-1) soil after the 28-d incubation.Soil microbial biomass C(mean 66 mg C kg^(-1) soil) did not change with flooding times in the unamended soil,and increased 1.4 times in the glucose-NH_4^+-amended soil.Ammonium immobilization and NO_2^- concentration in the aerobically incubated soil decreased with increasing flooding times,while NO_3^- concentration increased.It was found that flooding the Texcoco soil decreased the EC sharply,increased mineralization of glucose,stimulated nitrification,and reduced immobilization of inorganic N,but did not affect soil microbial biomass C.展开更多
基金National Natural Science Foundation of China (Grant No.30572376)
文摘In this study, a novel and simple high performance liquid chromatography with diode array detection （HPLC-DAD） method for the simultaneous qualitative and quantitative determination of 12 bioactive components in Gegen Qinlian pill was developed. The separation was performed on a Kromasil C18 column （250 mm×4.6 ram, 5.0 μm） by gradient elution with acetonitrile and 0.02 mol/L ammonium acetate （containing 0.3% triethylamine, and adjusted pH to 4.3 using 1% glacial acetic acid） as the mobile phase at a flow rate of 0.7 mL/min. Three different detection wavelengths （250, 280, 346 nm） were set at the maximum UV absorption wavelengths of these components. Twelve components （puerarin, daidzin, baicalin, wogonoside, liquiritin, berberine, palmatine, jatrorrhizine, glycyrrhizin, baicalein, wogonin and daidzein） were identified and determined using the developed method. All calibration curves showed good linear regression （r〉0.9995） within tested ranges. The injection precision, intra-day precisions and analysis repeatability were evaluated with the RSD values, which were no more than 0.97%, 1.69% and 1.71%, respectively. The recoveries were ranged from 97.4% to 100.2% with RSD values less than 1.87%. This readily available, low-cost and reliable HPLC-DAD method would improve the quality control of Gegen Qinlian pill.
基金supported by the 'Consejo Nacional de Cienciay y Tecnologia'(CONACyT,Mexico)(research grants Nos.32479-T and 39801-Z)
文摘Flooding an extremely alkaline(pH 10.6) saline soil of the former Lake Texcoco to reduce salinity will affect the soil carbon(C)and nitrogen(N) dynamics.A laboratory incubation experiment was done to investigate how decreasing soil salt content affected dynamics of C and N in an extremely alkaline saline soil.Sieved soil with electrical conductivity(EC) of 59.2 dS m^(-1) was packed in columns,and then flooded with tap water,drained freely and conditioned aerobically at 50%water holding capacity for a month.This process of flooding-drainage-conditioning was repeated eight times.The original soil and the soil that had undergone one,two,four and eight flooding-drainage-conditioning cycles were amended with 1000 mg glucose-^(14)C kg^(-1) soil and 200 mg NH_4^+-N kg^(-1)soil,and then incubated for 28 d.The CO_2 emissions,soil microbial biomass,and soil ammonium(NE_4^+),nitrite(NO_2^-) and nitrate(NO_3^-) were monitored in the aerobic incubation of 28 d.The soil EC decreased from 59.2 to 1.0 dS m^(_1) after eight floodings,and soil pH decreased from 10.6 to 9.6.Of the added ^(14)C-labelled glucose,only 8%was mineralized in the original soil,while 24%in the soil flooded eight times during the 28-d incubation.The priming effect was on average 278 mg C kg^(-1) soil after the 28-d incubation.Soil microbial biomass C(mean 66 mg C kg^(-1) soil) did not change with flooding times in the unamended soil,and increased 1.4 times in the glucose-NH_4^+-amended soil.Ammonium immobilization and NO_2^- concentration in the aerobically incubated soil decreased with increasing flooding times,while NO_3^- concentration increased.It was found that flooding the Texcoco soil decreased the EC sharply,increased mineralization of glucose,stimulated nitrification,and reduced immobilization of inorganic N,but did not affect soil microbial biomass C.
