Influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb(II) ion-selective electrode

Narender Kumar Joon, Ning He, Michal Wagner, Marité Cárdenas, Johan Bobacka, Grzegorz Lisak

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In this work, the influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb2+-selective electrode (Pb2+-ISE) was studied. The effects of bovine serum albumin (BSA) adsorption at the surface of the ion-selective membrane combined with electrode conditioning in phosphate-buffered saline (PBS) solution was elucidated by potentiometry and electrochemical impedance spectroscopy. The adsorbed BSA at the surface of the Pb2+-ISE slightly lowered the detection limit but did not influence the selectivity of the Pb2+-ISE towards the interfering ions studied (Cu2+, Cd2+). Conditioning of the Pb2+-ISE in 0.01 mol dm–3 PBS resulted in a super-Nernstian response which was related to fixation/extraction of Pb2+ in the ion-selective membrane via precipitation of Pb3(PO4)2 by PO43– anions present in PBS. By conditioning of the Pb2+-ISE in 0.01 mol dm–3 PBS + 1 mg/ml BSA it was possible to extend the linear response range of the Pb2+-ISE towards lower analyte concentrations. The utilization of this conditioning procedure was validated by determination of Pb2+ concentrations down to ca 20 ppb in aqueous samples by Pb2+-ISEs and by comparing the results with those obtained by ICP-MS.

Original languageUndefined/Unknown
Pages (from-to)490–497
JournalElectrochimica Acta
Publication statusPublished - 2017
MoE publication typeA1 Journal article-refereed


  • phosphate buffer
  • Electrochemistry
  • Protein adsorption
  • Potentiometric sensors

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