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SM ISO690:2012 DÎRU, Mariana, STÎMKOVSKAIA, Anna, REVENKO, M.. Potentiometric determination of the potassium in the presence of the ammonium ion with a tetraphenylborate-selective electrode. In: The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova, 28-30 mai 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Chimie al AȘM, 2014, p. 155. |
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The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova 2014 | ||||||
Conferința "The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova" Chișinău, Moldova, 28-30 mai 2014 | ||||||
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In many real objects along with potassium the ammonium ions are found. If for the Analyzing the results presented in the table, one may conclude that the values of the |
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<?xml version='1.0' encoding='utf-8'?> <resource xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns='http://datacite.org/schema/kernel-3' xsi:schemaLocation='http://datacite.org/schema/kernel-3 http://schema.datacite.org/meta/kernel-3/metadata.xsd'> <creators> <creator> <creatorName>Dîru, M.</creatorName> <affiliation>Universitatea de Stat din Moldova, Moldova, Republica</affiliation> </creator> <creator> <creatorName>Stîmkovskaia, A.</creatorName> <affiliation>Universitatea de Stat din Moldova, Moldova, Republica</affiliation> </creator> <creator> <creatorName>Revenco, M.D.</creatorName> <affiliation>Universitatea de Stat din Moldova, Moldova, Republica</affiliation> </creator> </creators> <titles> <title xml:lang='en'>Potentiometric determination of the potassium in the presence of the ammonium ion with a tetraphenylborate-selective electrode</title> </titles> <publisher>Instrumentul Bibliometric National</publisher> <publicationYear>2014</publicationYear> <relatedIdentifier relatedIdentifierType='ISBN' relationType='IsPartOf'></relatedIdentifier> <dates> <date dateType='Issued'>2014</date> </dates> <resourceType resourceTypeGeneral='Text'>Conference Paper</resourceType> <descriptions> <description xml:lang='en' descriptionType='Abstract'><p>In many real objects along with potassium the ammonium ions are found. If for the<br />determination of NH4<br />+ several relatively simple methods are known, then for K+ these possibilities<br />are less, and those are required more sophisticated equipment and expensive reagents. Using an<br />sensitive electrode in the presence of tetraphenylborate ions, we developed previously a method<br />for determination of the potassium content by the rest titration in samples that did not contained<br />ammonium [1,2].<br />Taking into account the fact that the tetraphenylborate anion can precipitate the<br />potassium ions as well as the ammonium ones, forming white substances, which are slightly<br />soluble and have the solubility product (PS(K[B(C6H5)4] near the value of 3.24.10-8 and<br />PS(NH4[B(C6H5)4] of 8.41.10-8 [3]), a new method for the determination of the content of<br />potassium in the presence of the ammonium ion has been developed. So, initially both cations<br />were precipitated with a known excess of tetraphenylborate by creating the conditions when the<br />values of the ion product exceed the product of solubility. Later, the excess of tetraphenylborate<br />has been potentiometrically titrated with a standard solution of potassium chloride using as<br />indicator the tetraphenylborate-selective electrode [1,2]. Through this operation the equivalent<br />and summary amount of both cations can be established. The content of ammonium is<br />determined by acid-base titration and, from the difference, the content of potassium, present in<br />the sample, can be calculated. A series of model samples with known concentrations of the<br />potassium and ammonium ions were analyzed.<br />Table. The results of determination of potassium and ammonium content in model samples</p><p>Analyzing the results presented in the table, one may conclude that the values of the<br />experimentally determined quantities are close to the real ones. This means, that during the<br />implementation of the experiment we do not commit systematic error. In the samples with an<br />ammonium content ≤ 10-6 mol, potassium can be only potenţiometrically determined. For these<br />conditions, the value of the ionic product for ammonium and tetraphenylborate is less than their<br />solubility product. The presented method is relatively simple, does not require sophisticated<br />equipment, used reagents being available.<br />References:<br />[1] Revenco, M.; Dîru, M.; Stîmcovschi, A. Conf. Ştiin. cu Part. Int.:Interferenţe Universitare–<br />Integrare prin Cercetare şi Inovare, Rezumatele comunicărilor, 2012, p. 71.<br />[2] Dîru, M. Autoref. tezei de dr. în ştiinţe chimice, Chişinău, 2012, 28 p.<br />[3] Kozitskii, V. In: Russian Chemical Bulletin, 1971, vol. 21 (1), 6-9.</p></description> </descriptions> <formats> <format>application/pdf</format> </formats> </resource>