Utilize este identificador para referenciar este registo: http://hdl.handle.net/10451/20887
Título: Effect of condensation phenomena on potentiometric measurements
Autor: Lito, M. J. Guiomar H. M.
Camoes, M. Filomena
Vicoso, Catarina M.
Palavras-chave: Chemistry, Analytical
Data: 2006
Citação: ANALYTICA CHIMICA ACTA. - Vol. 575, n. 1 (2006), p. 45-51
Resumo: Results of potentiometric analysis, namely those of pH measurements, depend on temperature control of the experimental setup, as it is expressed in the analytical law, the Nernst equation, starting from the primary level, where reference values are conventionally assigned to standard solutions, through the whole traceability chain, down to the service laboratory. Fundamental studies of pH standards, based on the measurement of the potential of an electrochemical cell without transference, known as Harned cell, containing a platinum-hydrogen electrode and a silver-silver chloride reference electrode, refer condensation phenomena on the portions of the cell walls which are not immersed in the thermostatic bath, as one of the major sources of erTor in the assessment of both the silver-silver chloride electrode standard potential and on pH values. In this work such effect, which is bound to happen due to significant temperature differences between the ambient air temperature and the water bath, has been quantified, presenting an original contribution to the improvement of the quality of potentiometric analysis results. This was possible due to the availability of a climatic cabin "WALKIN" with a temperature control of +/- 0.01 degrees C, which permitted that temperature gradients were built between the thermostat water bath (controlled to 0.005 degrees C where cells filled to about 2/3 full were immersed up to 90% of their height, and the surrounding environment. (c) 2006 Elsevier B.V. All rights reserved.
URI: http://hdl.handle.net/10451/20887
DOI: http://dx.doi.org/10.1016/j.aca.2006.05.078
ISSN: 0003-2670
Aparece nas colecções:FF - Produção Científica 2000-2009

Ficheiros deste registo:
Não existem ficheiros associados a este registo.

FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpace
Formato BibTex MendeleyEndnote 

Todos os registos no repositório estão protegidos por leis de copyright, com todos os direitos reservados.