排序方式: 共有41条查询结果,搜索用时 15 毫秒
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对沉淀分离EDTA滴定法测定锌精矿中锌含量的测量不确定度来源进行了分析,并对EDTA标准溶液的滴定度、试样的质量、滴定体积、测定过程随机误差等不确定度分量进行了分析和量化,合成标准不确定度和扩展不确定度分别为0.20%和0.40%。 相似文献
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《Analytical letters》2012,45(5):507-517
Abstract When a solution containing a single monobasic weak acid is titrated potentiometrically with a strong base, non-linear regression analysis of the data yields a random scatter of the residuals around the best fit to the appropriate equation. If the same equation is used when a second weak acid is also present, systematic errors arise and yield a deviation plot having a characteristic shape. If the amplitude of that plot is substantially larger than the random error of measurement, the presence of the second acid can be detected, and its concentration can then be evaluated by non-linear regression onto the equation that takes its presence into account. The amplitude increases as the relative concentration of the second acid increases, and as the difference between the values of pKa for the two acids increases. Examination of these dependences shows, for example, that it should be possible to detect 1 per cent of an impurity for which pKa differs by 0.57 unit from that of the major component. 相似文献
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Rákosi Éva Dávid 《Mikrochimica acta》1989,97(5-6):387-391
Determination of phosphate was performed with lanthanum nitrate in an aqueous medium in the presence of a haematoxylin indicator. Following processing of the organic phosphorus compound in a Schöniger flask the mixture was acidified and boiled off and then the pH was adjusted to 6.1–6.3 with hexamethylene tetramine. The hot solution was titrated with lanthanum nitrate. The orange colour of haematoxylin changed to violet-blue at the point of equivalence, while precipitation of lanthanum phosphate was observed. 相似文献
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介绍一种新型气压式滴定仪的结构、性能、特点及使用方法。该仪器能迅速、准确地加液调零,使用方便,克服了旧式滴定管漏液、取液时易玷污、加液调零较麻烦等缺点,在适当的情况下还可以作为移液管使用。 相似文献
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在前文中曾提出,第一终点PH>3.7的情况下,以多元酸标准溶液的半中和点为第一点,测定各组分酸含量的方法。在此基础上,本文在理论上明确了影响各组分酸含量测定的因素,从而提出第一终点PH不同的情况下,Ka1/Ka2倍数不同时可准确滴定的Ve2/V^Te值的计算方法。实验结果表明,在此条件下结果是可靠的。 相似文献
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Marjan Dermelj Zdenka Šlejkovec Anthony R. Byrne Boris Kenda Tatjana Čerk Bogomil Gorenc 《Mikrochimica acta》1991,103(3-4):151-157
A comparative study of the determination of iodine in mineral waters is presented. Iodine was first determined by a standard titrimetric method and the results obtained were compared with those obtained by the faster and more sensitive radiochemical neutron activation method. For a series of waters, the results obtained by the two techniques were in fair agreement for the higher concentration levels of iodine, but for very low iodine levels the titrimetric method was insufficiently sensitive. The RNAA procedure was checked by standard addition experiments, and shown to be also valid when iodine was present as iodate.The paper was presented in part at the ISM XI, Wiesbaden, August 1989 相似文献
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Bo Ilic 《Transactions of the American Mathematical Society》1998,350(4):1643-1661
The locus of double points obtained by projecting a variety to a hypersurface in moves in a linear system which is shown to be ample if and only if is not an isomorphic projection of a Roth variety. Such Roth varieties are shown to exist, and some of their geometric properties are determined.