Effect of interferents present in the internal solution or in the conducting polymer transducer on the responses of ion-selective electrodes |
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Authors: | Agata Michalska Marcin Ocypa Krzysztof Maksymiuk |
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Institution: | (1) Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland |
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Abstract: | The effect of interferents present on the opposite side of the Pb2+-selective membrane has been studied for both internal solution and all-solid-state sensors with a conducting polymer (CP)
transducer. For interferents with moderate selectivity coefficients (sodium cations) present in the internal solution or in
the CP transducer phase, super-Nernstian responses were obtained. For sensors containing strongly discriminated interferents
(lithium ions), however, responses typical of conventional electrodes are observed, despite the low activity of primary ions
on the opposite side of the membrane. This effect is attributed to hindered incorporation of interfering ions into the membrane,
which also impairs the long term stability of the potential. Because of the relatively small absolute amounts of interferents
in the transducer of all-solid-state sensors, their exchange for primary ions occurs quickly. Thus, transformation of the
sensor to one with a micromolar detection limit and high potential stability is observed.
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Keywords: | Ion-selective electrodes All-solid-state potentiometric sensor Selectivity Stability |
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