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1.
ICP-AES法快速测定葡萄酒中S、P、Fe   总被引:1,自引:0,他引:1  
详细研究了ICP-AES法测定葡萄酒中S、P、Fe的各种条件.以S182.0nm,P177.4nm,Fe240.4nm为测定波长,葡萄酒经直接稀释5倍后可一次完成S、P、Fe的测定,方法简单快速.成功测定了几种葡萄酒中微量S、P、Fe,检出限分别为0.008mg/L、0.01mg/L、0.01mg/L,回收率为96.5%~108.5%.  相似文献   

2.
锑磷钼蓝-纳米金共振散射光谱法测定抗坏血酸   总被引:2,自引:0,他引:2  
在硫酸介质中,纳米金在774 nm处产生一个较强的共振散射峰;磷钼酸与酒石酸锑钾形成的三元杂多酸可被抗坏血酸还原形成锑磷钼蓝,导致774 nm处共振散射峰的强度降低.抗坏血酸在0.10~16.0 mg/L与共振光散射强度降低值△I呈良好的线性关系,其回归方程为△I=21.1C-2.0(C的单位为mg/L),相关系数为r=0.9981,方法的检出限为0.05 mg/L.本法用于药品、注射液、饮料中抗坏血酸的测定,具有操作简便、快速、稳定等特点,相对标准偏差为1.78%~4.62%.  相似文献   

3.
酶解法对提取虎杖中白藜芦醇的应用及工艺优化   总被引:1,自引:0,他引:1  
在酶法提取虎杖中白藜芦醇的过程中,对原料经酶解处理后的乙醇提取工艺进行研究.研究结果表明,最佳提取工艺条件是:体积分数为40%乙醇,以液固比20:1,在40℃提取40 min,提取次数为1次.与原料未经酶解处理的直接醇提法的提取工艺条件比较,原料经酶解处理后,可以在较低的乙醇浓度、较低的温度下,提取较短的时间即可达到较好的提取效果.经HPLC分析,从虎杖中提取白藜芦醇的得率达13.85 mg/g,粗提物中白藜芦醇纯度达22.7%.  相似文献   

4.
采用高效液相色谱法测定不同饮料中的糖精钠,对色谱柱的类型及色谱分离条件进行了优化。结果表明:当色谱柱为氰基柱,流动相为乙腈-0.02 mol/L乙酸铵溶液(15∶85,V∶V),流速为0.6 mL/min,柱温为25℃,检测波长为230 nm时,糖精钠的分离效果最佳。该方法的线性方程为Y=0.80X+0.33,线性范围是0.01~20 mg/L,线性相关系数r=0.999 79,检出限为0.003 3 mg/L。建立的分析方法能够有效检出饮料样品中的糖精钠,目标分析物不受干扰物质的影响,检出浓度在1.68~20.25 mg/L之间,加标回收率在70.37%~124.10%之间,相对标准偏差在0.17%~9.39%之间。  相似文献   

5.
荷移反应分光光度法测定咖啡因   总被引:3,自引:0,他引:3  
研究了咖啡因与氯冉酸之间的荷移反应 .测得络合物在乙醇介质中络合比为 1∶1 .在测定波长 31 9nm处 ,络合物的表观摩尔吸光系数为 1 .92× 1 0 4 L·mol- 1 ·cm- 1 ,咖啡因浓度在 0 .8mg/L~ 1 1 .0mg/L范围内符合比尔定律 ,平均加标回收率为 95 .2 %~ 1 0 1 .6% ,相对标准偏差为 1 .5 %~ 2 .3% .  相似文献   

6.
浸没式MBR处理洗浴废水   总被引:1,自引:0,他引:1  
以规模3 m^3/d浸没式MBR中试设备进行了洗浴废水处理效果的实验研究.原水COD为53.5~341.0 mg/L, NH4-N为7.2~39.1 mg/L,LAS为1.2~5.8 mg/L,浊度为13~152 ntu;经膜生物反应器的处理后出水COD为8.2~23.5 mg/L,去除率为90.9%, NH4-N为0.2~13.5 mg/L,去除率为71.0%,LAS为0~0.2 mg/L,去除率在90%以上, 浊度为1~7 ntu,去除率92%.说明膜生物反应器处理洗浴废水能够取得良好的效果,尤其是进水有机物质量浓度变化较大的情况下,仍然保持好的去除效果.  相似文献   

7.
该发明提供了一种低酸度的乙醇产品,所述的乙醇产品中乙醇含量为99.9~92 wt%,以乙酸计的酸值为0~5 mg/L,紫外透光率在220 nm处为50~95。  相似文献   

8.
建立了离子色谱-紫外检测器测定食品中亚硝酸盐和硝酸盐的分析方法。样品经超声提取后,以3.6 mmol/L Na_2CO_3溶液为流动相,经Metrosep A supp7-250阴离子交换分析柱,于210 nm处进行紫外检测。结果表明该方法在0.025~0.20 mg/L(亚硝酸盐)、0.10~2.0 mg/L(硝酸盐)范围内具有良好的线性关系,相关系数r均在0.999以上。亚硝酸盐和硝酸盐的检出限分别为0.004 5 mg/L和0.017 2 mg/L,检测下限分别为0.018 mg/L和0.068 mg/L,实际样品加标回收率分别为81.3%~87.3%和98.3%~103.1%,相对标准偏差小于5%。实验表明,该方法简便、灵敏,可用于测定食品中的亚硝酸盐和硝酸盐。  相似文献   

9.
研究了7,7,8,8-四氰基对二次甲基苯醌(TCNQ)与烟碱的荷移反应, 确定 了反 应条件. TCNQ与烟碱形成络合物的反应在743 nm和842 nm处有较强光吸收, 表观摩尔吸 光 系数分别是4.84×103 L· mol-1·cm-1和8.82 ×103 L· mol-1·cm-1. 在乙醇介质中, 烟碱 的浓度在3~35 mg/L与吸光度关系符合朗伯-比尔定律; 该方法重现性好、 灵敏度高、 操 作简单 , 用于测定烟草中烟碱含量, 精密度好, 相对标准偏差为1.4%(n=9), 烟碱的回收 率为98%~103%, 结果令人满意.  相似文献   

10.
提出了一种反相高效液相色谱法同时测定4种苯二氮卓艹类药物的分析方法.考察了4种苯二氮卓艹类药物的保留值与流动相组成、流速、pH及柱温等色谱条件的关系,优化了色谱条件.确定了以ODSHypersil为色谱柱,甲醇-水(51∶49;V/V,用氨水调pH7.8)为流动相,流速为0.8mL/min,柱温为45℃,检测波长为220nm的最佳色谱条件.甲苯作为内标物,以内标法峰面积定量.硝西泮,地西泮,三唑仑和艾司唑仑线性范围分别是0.1mg/L~320mg/L,0.2mg/L~320mg/L,0.1mg/L~320mg/L和0.08mg/L~320mg/L;检测限分别为0.1mg/L,0.2mg/L,0.1mg/L和0.08mg/L.该方法用于尿液中的苯二氮卓艹类药物的测定.其回收率为97.0%~108.7%,标准偏差为1.7%~3.0%(n=7).该方法简单、快速、精确、灵敏、重复性好.  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.
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   

14.
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   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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