Phytic acid@Ag-based all-solid-state ion selective electrode for potentiometric detection of Cu ²⁺

In this study, a novel all-solid-state ion selective electrode (ASS-ISE) was developed for the detection of Cu ²⁺ by open circuit potential (OCP) based on phytic acid (PA)@Ag, which forms a thin anion layer interacting with positive charged Cu ²⁺ . Due to the excellent conductivity and complexing ability with multi-chelating features, PA can selectively recognize metal ions and execute ion-electron conduction. Moreover, with the assistance of Ag nanoparticles, multiple PA molecules were connected, forming a network structure with the improved conductivity and stability. After optimizing the thickness of PA@Ag film, this ASS-ISE gave a near Nernstian behavior (31.3 ± 1.8 mV/dec) towards the variation of Cu ²⁺ concentration in the range of 1.0 × 10 ⁻⁵ to 1.0 × 10 ⁻³ mol/L with a detection limit of 2.7 × 10 ⁻⁶ mol/L, and presented excellent selectivity and stability. Furthermore, it was applied in the analysis of Cu ²⁺ in environmental waters with the satisfactory recoveries, and the results were consistent well with those obtained by inductively coupled plasma atomic emission spectrometer, providing a promising alternative for the on-site detection of Cu ²⁺ with simplicity and reliability.