[Objective] The research aimed to discuss extraction of the chlorophyll a from phytoplankton by hot-ethanol method. [Method] The measurement method of chlorophyll a was improved. By contrast test, the best extraction ...[Objective] The research aimed to discuss extraction of the chlorophyll a from phytoplankton by hot-ethanol method. [Method] The measurement method of chlorophyll a was improved. By contrast test, the best extraction temperature and time of chlorophyll a by hot-ethanol meth- od were studied. Meanwhile, we contrasted hot-ethanol method with specification. I Result] It was simple to use hot-ethanol method to extract chlo- rophyll a from phytoplankton, and it was safe and reliable. When extraction temperature was 75℃ , extraction efficiency of the chlorophyll a was the highest using hot ethanol to hot for 3 min. Chlorophyll a extracted by specification presented significant positive correlation with that by hot-ethanol method. Extraction efficiency of the hot-ethanol method was higher than that of the specification. [ Condusion] The research could provide theoretical reference for extraction of the chlorophyll a from phytoplankton in surface water.展开更多
Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% p...Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% platinum per carbon were prepared by the three methods; their morphology and electrocatalytic activities were characterized.The 20 wt.% Pt-WO3/C catalyst prepared by the co-impregnation/EG method presented the optimal dispersion with an average particle size of 4.6 nm and subsequently the best electrocatalytic activity,and so,it was further characterized.Its anodic peak current density for ethanol oxidation from linear sweep voltammetry （LSV） is 7.9 mA·cm^-2,which is 1.4 and 5.2 times as high as those of the catalysts prepared by co-impregnation/NaBH4 and co-impregnation/ HCOOH reduction methods,2.1 times as high as that of the 10 wt.% Pt-WO3/C catalyst prepared by co-impregnation/EG method,respectively.展开更多
With rutin standard sample as the comparison, flavonoid extraction rate as an indicator, UV-2450 ultraviolet visible light spectrophotometer to measure flavonoid content in planted Trollius chinensis through orthogona...With rutin standard sample as the comparison, flavonoid extraction rate as an indicator, UV-2450 ultraviolet visible light spectrophotometer to measure flavonoid content in planted Trollius chinensis through orthogonal experiment, this experiment optimizes process condition of flavonoid in Trollius chinensis through water extraction and ethanol extraction. The result shows that flavonoid extraction rate of Trollius chinensis through ethanol extraction method is obviously higher than water extraction, and the optimal extraction process condition is： ethanol concentration is 75%, extraction time is 90min, extraction times are 3, and fluid material ratio is 20：1.展开更多
文摘[Objective] The research aimed to discuss extraction of the chlorophyll a from phytoplankton by hot-ethanol method. [Method] The measurement method of chlorophyll a was improved. By contrast test, the best extraction temperature and time of chlorophyll a by hot-ethanol meth- od were studied. Meanwhile, we contrasted hot-ethanol method with specification. I Result] It was simple to use hot-ethanol method to extract chlo- rophyll a from phytoplankton, and it was safe and reliable. When extraction temperature was 75℃ , extraction efficiency of the chlorophyll a was the highest using hot ethanol to hot for 3 min. Chlorophyll a extracted by specification presented significant positive correlation with that by hot-ethanol method. Extraction efficiency of the hot-ethanol method was higher than that of the specification. [ Condusion] The research could provide theoretical reference for extraction of the chlorophyll a from phytoplankton in surface water.
基金supported by the National Basic Research and Development Program of China (No. 2009CB220100)Beijing Excellent Talent Support Program (No. 20071D1600300396)
文摘Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% platinum per carbon were prepared by the three methods; their morphology and electrocatalytic activities were characterized.The 20 wt.% Pt-WO3/C catalyst prepared by the co-impregnation/EG method presented the optimal dispersion with an average particle size of 4.6 nm and subsequently the best electrocatalytic activity,and so,it was further characterized.Its anodic peak current density for ethanol oxidation from linear sweep voltammetry （LSV） is 7.9 mA·cm^-2,which is 1.4 and 5.2 times as high as those of the catalysts prepared by co-impregnation/NaBH4 and co-impregnation/ HCOOH reduction methods,2.1 times as high as that of the 10 wt.% Pt-WO3/C catalyst prepared by co-impregnation/EG method,respectively.
文摘With rutin standard sample as the comparison, flavonoid extraction rate as an indicator, UV-2450 ultraviolet visible light spectrophotometer to measure flavonoid content in planted Trollius chinensis through orthogonal experiment, this experiment optimizes process condition of flavonoid in Trollius chinensis through water extraction and ethanol extraction. The result shows that flavonoid extraction rate of Trollius chinensis through ethanol extraction method is obviously higher than water extraction, and the optimal extraction process condition is： ethanol concentration is 75%, extraction time is 90min, extraction times are 3, and fluid material ratio is 20：1.
