Volume 4, Issue 1, 1986
2nd October, 2022
The Design and Application of Lithium Ion-Selective Electrodes for Clinical Purposes
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by V. P. Y. Gadzekpo, G. J. Moody, J. D. R. Thomas
5-32
DOI: doi: 10.4152/pea.198601005
Ideally a lithium ion-selective electrode should detect 0.1mM lithium in the presence of about 150mH sodium as well as the usual blood components. About 40 cyclic and acyclic ionophores have been examined potentiometrically. PVC electrodes with three such ionophores have been evaluated for the analysis of real sera using a micro conduit flow injection technique. Each of the sensors suffered serious interferences from unidentified serum components.
Construção e Avaliação de um Eléctrodo Selectivo para Anião Brometo com Sensor de Hg2Br2 / HgS Aplicado sobre Resina Condutora
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by José L. F. C. Lima, Adélio A. S. C. Machado
33-50
DOI: doi: 10.4152/pea.198601033
A bromide selective electrode based on mercury salts applied to a support of electrically conductive epoxy has been prepared and tested. A 2:1 (by weight) mixture of mercurous bromide and mercuric sulphide was used as sensor. Response characteristics to bromide and mercurous ion were determined by standard procedures, showing that the electrode responds to bromide as a second kind electrode. The electrode shows a better performance than the PHI 91300 Graphic Controls commercial electrode, which uses the same type of sensor.
Activity Coefficients of Tetraethyl-ammonium Perchlorate in Aqueous Solutions
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by Joan Torrent, Fausto Sanz
51-59
DOI: doi: 10.4152/pea.198601051
Mean ionic activity coefficients of tetraethyl-ammonium(TEA) Perchlorate in aqueous solutions have been calculated from the effect of the TEA salt on the perchloric acid activity coefficients. Acid activity coefficients have been determined by measuring the emf of a concentration cell.
Parameters º, ^ and Cø in Pitzer's equations have also been calculated for a series of substituted ammonium salts using both previously reported data and our TEA Perchlorate values.
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Keywords: activity coefficients, tetraethylammonium perchlorate, electrochemical cell measurements.
Determination of Clobazam by Differential Pulse Polarography
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by C. González Pérez, J. Hernández Méndez, M. I. González Martin et al.
61-67
DOI: doi:10.4152/pea.198601061
The polarographic behaviour of clobazam was investigated over a wide pH range. Different types of peaks were obtained depending on the pH. Characterization of the electroactive process included an examination of the degree of reversibility, electrocapillary curves, influence of surfactant agents and the effect on the peak current of pulse amplitude, ionic strength, drop time, temperature and clobazam concentration. A method for the determination of clobazam, with a detection limit of 46x10"7 M and a relative standard deviation of 0.97% is proposed.
