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1.
槲皮素与锆形成二元荧光络合物,SDS对体系有强烈的增敏作用,研究并建立了测定槲皮素的荧光光度法。在0.48mol/LHCl介质中,槲皮素浓度在0.072~7.76μg/mL范围内与其荧光强度呈良好的线性关系,其线性回归方程为γ=7.1829x+5.4025,相关系数r=0.9958,检出限为0.046μg/mL。该法用于银杏叶片制剂中总黄酮醇苷含量(以槲皮素计)的测定,其回收率为97.60%-102.2%,结果较为理想。  相似文献   

2.
沙枣叶中提取的总黄酮化合物对羟基自由基的清除作用   总被引:6,自引:0,他引:6  
以青海本地沙枣叶为原料,利用水作为提取介质对黄酮类化合物进行了提取,并对提取液中黄酮类化合物对羟基自由基的清除作用进行了研究。结果表明:当黄酮浓度为400μg/mL时,对羟基自由基的清除率为22.3%;黄酮浓度在50~400μg/mL范围内其清除率与浓度剂量呈正相关。  相似文献   

3.
提出了在六次甲基四胺一盐酸缓冲溶液(pH5.5)中,硝酸铅与磷酸根反应生成磷酸氯化铅复盐沉淀,运用方波伏安法快速测定过量的铅离子从而间接测定无机磷含量。在最佳实验测定条件下方波伏安峰高ip(μA)与磷的浓度在0.2~20μg/mL内有良好的线性关系,回归方程为ip=54.82—2.39c,相关系数r=0.9876,检出限为0.085μg/mL,相对标准偏差(RSD)为2.44%,加标回收率在95%~99%。方法具有准确性好,操作简便的特点,用于饲料中磷含量的测定,结果满意。  相似文献   

4.
毛细管色谱法测定头孢美唑中的有机溶剂残留量   总被引:1,自引:0,他引:1  
采用毛细管气相色谱法,以叔丁基甲醚为内标,用Agilent DB-200毛细管气相色谱柱和氢焰离子化检测器.同时测定了头孢美唑中甲醇、乙醇、二氯甲烷、三乙胺、乙酸乙酯、苯甲醚等6种有机溶剂残留量.6种溶剂的线性范围分别为0~480μg/mL(r=0.9996)、0—800μg/mL(r=0.9994)、0~96μg/mL(r=0.9990)、0~800μg/mL(r=0.9993)、0~800μg/mL(r=0.9995)、0~800μg/mL(r=0.9993);平均回收率分别为100.1%、100.5%、101.2%、100.1%、100.7%和100.4%;相对标准偏差分别为0.90%、1.30%、1.18%、1.23%、1.52%、1.41%(n=9).  相似文献   

5.
银杏叶提取物中总黄酮含量的分析方法研究   总被引:2,自引:0,他引:2  
提出了一种简便、灵敏地测定银杏叶提取物中总黄酮含量的新方法。实验结果表明银杏叶提取物经酸性条件下加热水解,使黄酮苷转化为苷元再与Al3+配位,所形成的配合物具有较强的荧光,可以槲皮素为标准品,采用荧光光度法测定其总黄酮含量。在选定条件下,槲皮素的浓度与荧光强度成线性关系,线性范围:0000?75~050?μg/mL, 检测限:045?g/mL(S/N=3),回归方程: If=7799?48+63210?86ρ×107(μg/mL),相关系数R=0999?9(P<0000?1),并用标准加入法进行回收实验和银杏叶提取物(GBE)中的总黄酮含量的测定,结果令人满意。  相似文献   

6.
目的:采用高效液相色谱法测定贯叶连翘中的金丝桃素、黄酮(槲皮素)的含量。方法:色谱柱为Phenomenex LunsC18(4.6mm×150mm,5μm),检测波长分别为590nm和360nm,流动相分别为甲醇:0006mol/L磷酸氢二钠溶液(87:13)和甲醇:水:磷酸(55:44.8:0.2)。结果:线性范围分别在0.027-0.135μg和0.052~0.26μg内良好,回收率分别为:98.39%(n=5)和98.85%(n=5)。RSD分别为0.78%和1.02%。结论:方法能用于贯叶连翘中的金丝桃素、黄酮(槲皮素)的含量测定。关键词:贯叶连翘;槲皮素;金丝桃素;含量测定  相似文献   

7.
酸性高锰酸钾化学发光体系测定针剂中的头孢噻肟钠   总被引:3,自引:1,他引:3  
头孢噻肟钠碱性水解产物与高锰酸钾反应可产生微弱的化学发光,多聚磷酸对其有强烈的增敏作用,据此建立了一种简单、快捷、灵敏的流动注射化学发光测定头孢噻肟钠的新方法.化学发光信号ICL与头孢噻肟钠质量浓度C在0.02-20μg/mL和20~120μg/mL范围内呈良好的线性关系,回归方程分别表示为ICL=3.169+20.961C(r=0.9998,n=9);ICL=147.5+14.752C(r=0.9994,n=9),方法的检出限为20ng/mL.对5μg/mL头孢噻肟钠进行11次平行测定,相对标准偏差为0.8%,用本法对针剂中头孢噻肟钠的含量进行了测定,得出了令人满意的结果.  相似文献   

8.
新疆红景天中红景天苷含量的测定   总被引:1,自引:0,他引:1  
用反相高效液相色谱法,流动相为甲醇-0.1mol/L磷酸二氢钠(15:85),紫外检测波长为280nm,流速1.0mL/min,测定新疆产红景天中红景天苷含量,结果表明,红景天苷对照品在10~320μg/mL内线性关系良好,r=0.999。平均加样回收率为96.5%;RSD为3.4%。稳定性良好。该法简便,分离完全,结果可靠,适用于红景天苷的含量测定。  相似文献   

9.
基于六价铬与碘化钾反应生成了单质碘,碘可以使罗丹明B发生荧光猝灭,从而间接测定六价铬的含量.六价铬浓度在0.01~0.5μg/mL围内,荧光强度差值与六价铬浓度呈线形关系,线性回归方程为△F=121.58CCr(VI)(μg/mL)+16.17,相关系数r=0.9990,检测限为2.4ng/mL.该方法简便,快速,灵敏度高,已用于环境样品中六价铬的测定,回收率在99.8%~104.2%,结果满意.  相似文献   

10.
高锰酸钾在酸性介质中能氧化扑尔敏并产生弱的化学发光,甲醛的存在能大大增强化学发光强度。基于此发现,建立了一种测定扑尔敏的流动注射化学发光分析法。测定扑尔敏的线性范围为0.4~50μg/mL,方法的检出限为0.2μg/mL。对浓度为4.0μg/mL的扑尔敏溶液进行11次平行测定的相对标准偏差为1.4%,样品测定频率达到120h^-1。该方法用于药物制剂中扑尔敏含量的测定。并与药典标准方法进行了对照,结果一致。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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