PVC-Based Ion-Selective Electrodes with a Silicone Rubber Outer Coating with Improved Analytical Performance

Narender Joon, Ning He, T Ruzgas, Johan Bobacka, G Lisak

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    Abstract

    An outer layer of pure silicone rubber (SR), i.e. SR without any plasticizer, ionophore, or lipophilic anion, was applied on top of a conventional poly(vinyl chloride) (PVC) based K+-selective membrane in a solid-contact ion-selective electrode (SC-ISE). The influence of the outer SR coating on the analytical performance of the K+-ISEs was studied. The presence of the SR coating did not affect the selectivity of the SC-ISE, indicating that the plasticizer, ionophore, and lipophilic anion are spontaneously distributed from the PVC-based membrane into the SR layer. This was confirmed by electrochemical impedance spectroscopy (EIS). Interestingly, the reproducibility of the standard potential of the conditioned SC-ISE was significantly improved from E-0 +/- 35.3 mV to E-0 +/- 3.5 mV simply by adding the SR coating on top of the plasticized PVC based K+-selective membrane. Moreover, the adsorption of bovine serum albumin (BSA) was significantly reduced at the SR coated ion-selective membrane. Thus, the addition of a SR coating on a plasticized PVC ion-selective membrane seems to be a feasible method to improve the analytical performance and to reduce the biofouling of potentiometric ion sensors.
    Original languageUndefined/Unknown
    Pages (from-to)10524–10531
    Number of pages8
    JournalAnalytical Chemistry
    Volume91
    Issue number16
    DOIs
    Publication statusPublished - 2019
    MoE publication typeA1 Journal article-refereed

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