A solid-contact Pb²⁺- selective electrode based on electrospun polyaniline microfibers film as ion-to-electron transducer

Electrospun polyaniline (PANI) microfibers are applied as ion-to-electron transducer in solid contact Pb²⁺-ion-selective electrode (GC/s-PANI/Pb²⁺-ISE). The corresponding electrode shows a Nernstian slope of 28.4 mV/decade, and a detection limit of 6.3 × 10⁻¹⁰ M can be acquired within a range of 10⁻⁹–10⁻³M Pb(NO₃)₂, with a response time shorter than 10s. The GC/s-PANI/Pb²⁺-ISE performs higher capacitance and lower impedance than the drop-coating GC/d-PANI/Pb²⁺-ISE measured by CV and EIS, demonstrating faster ion-to-electron transportation. Additionally, in the water layer test, interfacial water film is shown to be eliminated in the GC/s-PANI/Pb²⁺-ISE. The developed electrode is applied to the determination of lead in real tap water, and the corresponding results are in compliance with those determined by atomic absorption spectrometry (AAS) method. This study targeted at PANI microfibers demonstrates a novel strategy of boosting potential stability and decreasing detection limit for solid contact ion-selective electrodes.