Potentiometric determination of sulphur in solid samples with a sulphide selective electrode
Potentiometric determination of sulphur in solid samples with a sulphide selective electrode
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DOI：
10.1016/s0003-2670(98)00673-4
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发表时间：
1999-01-25
影响因子：
6.2
通讯作者：
Fuertes, AB
中科院分区：
文献类型：
--
作者：
García-Calzada, M;Marbán, G;Fuertes, AB
迄今为止，固体样品中存在的低硫量的电位分析是通过将固体样品还原并在适当的溶液（碱性和抗硫氧化）中吸收形成的H2S（g）来进行的。然后通过直接测量或通过硫化物选择性电极的电位滴定来分析溶液的总硫含量。然而，所有报道的技术都利用了已知硫含量的固体样品的先前标准化，以避免在长滴定时间期间溶液中硫的损失所产生的误差。对于硫浓度低于10（-3）M的情况，这些损失尤其显著。标准化是一个耗时的过程，它引入了一个额外的误差，假设硫损失的线性依赖于溶液中的硫浓度。在这项工作中，标准化被证明是不必要的，如果电位滴定的溶液中的硫含量的直接测量通过硫选择性电极。通过这种方式，分析时间大大缩短，因此硫损失最小化。因此，标准化被用较少的已知硫浓度的溶液对电极进行耗时较少的校准所取代。特别推荐用于硫浓度低于10（-3）M的溶液。(C)1999 Elsevier Science B. V.保留所有权利。
Up to date the potentiometric analysis of low sulphur amounts present in solid samples has been made by reducing the solid sample and absorbing the formed H2S(g) in an appropriate solution (basic and resistant to sulphur oxidation). The total sulphur content of the solution is then analysed either by direct measurement or by potentiometric titration via a sulphide selective electrode. However, all the reported techniques make use of a previous standardisation with solid samples of known sulphur content, in order to avoid the error produced by the losses of sulphur in solution during the long titration times. These losses are especially significant for sulphur concentrations below 10(-3) M. Standardisation is a time-consuming process, which introduces an additional error by assuming a linear dependence of the sulphur losses on the sulphur concentration of the solution.In this work, standardisation is proven to be unnecessary if the potentiometric titration of the solution is substituted by the direct measurement of its sulphur content via the sulphur selective electrode. In this way the analysis times are drastically reduced, and therefore, the sulphur losses are minimised. Standardisation is thus replaced by a less time-consuming calibration of the electrode with few solutions of known sulphur concentration. This method is recommended especially for solutions with sulphur concentrations below 10(-3) M. (C) 1999 Elsevier Science B.V. All rights reserved.