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排序方式: 共有250条查询结果,搜索用时 15 毫秒
1.
高效阴离子交换色谱法测定毛头鬼伞多糖中的单糖组成 总被引:2,自引:0,他引:2
本文采用高效阴离子交换色谱—脉冲安培检测器(HAPEC-PAD),建立了一种测定多糖中单糖比例的方法。以NaOH为淋洗液、CarboPac^TM A20预处理柱,CarboPac^TMPA20分离柱,金工作电极,Ag/AgCl参比电极,8种自然界中常见单糖标准品做混合标样,探索方法可行性。在淋洗液浓度为2.5mmol/L时,各种单糖组分得到有效分离,其线性和重现性均良好并在此基础上测定了毛头鬼伞多糖中单糖比例;与传统的方法相比,此方法具有前处理简单、灵敏度高、节省时间和试剂等优点。 相似文献
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以水溶液体系作为对照,利用分光光度法研究了W/O型微乳液体系中水杨酸(SA)和水杨酸甲酯(MS)清除超氧阴离子自由基(·O2-)的性能.结果发现,在水浴时间为20min、pH值为8.20和邻苯三酚加入量适宜的情况下,W/O微乳液体系中SA、MS对·O2-的清除率分别可达72.92%、81.47%.微小的pH值变化会引起邻苯三酚自氧化速率的显著变化,电解质溶液对其也有明显的影响,但对SA、MS清除·O2-的能力影响不大. 相似文献
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将星杂288鸡种蛋960枚随机分为4组,进行3周孵化试验,各组空气负氧离子浓度分别为200000、100000、50000和40个/cm3。再取孵出的雏鸡120只随机分为4组,进行6周饲养试验,所设负氧离子浓度分别为100000、50000、25000和30个/cm3。结果表明:(1)200000和100000个/cm3负氧离子有助于胚胎的生长发育,能提高种蛋的孵化率;(2)50000个/cm3负氧离子可降低雏鸡料肉比和死亡率,并能促进雏鸡的生长发育,改善雏鸡的某些血液生理生化指标;(3)25000个/cm3以上的负氧离子对孵化和育雏的空气环境有一定净化作用。 相似文献
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Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran 总被引:1,自引:0,他引:1
The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity (TAA),superoxide anion radical scavenging activity (SARSA),active oxygen scavenging activity (AOSA),and DPPH (1,1-diphenyl-2 picrylhydrazyl free radical) radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc (antiscorbutic vitamin,vitamin C),and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing. 相似文献
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The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variable charge soils, with different surface charge properties were studied. Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl- > NO3- > ClO4-, indicating the difference of the nature among these three anions. For Ferralsol in the same concentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersect at certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in the perchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in the chloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acid anion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salt effect (PZSE) on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSE for sulfate adsorption. For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO3 solution and to have a typical PZSE for sulfate adsorption in NaClO4 solution. For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO3 solutions and converged to pH 6.5 in NaClO4 solution. 相似文献