# 3D Printed Ion-Selective Electrodes Enriched with ZnO Nanoparticles for Potassium Detection

## TL;DR

This paper introduces a new method to create potassium-detecting sensors using 3D printing and zinc oxide nanoparticles, resulting in improved performance and faster response times.

## Contribution

The novel use of 3D printing and ZnO nanoparticles to fabricate high-performance potassium-selective electrodes.

## Key findings

- Incorporating ZnO nanoparticles significantly enhanced the electrode slope and detection performance.
- Graphite-based membranes showed a fast response time with potential stabilization within 3–7 seconds.
- The optimized membrane achieved near-Nernstian behavior with a detection limit of 2.06 × 10−5 mol L−1.

## Abstract

Ion-selective electrodes (ISEs) are widely used analytical tools for the determination of specific ions in a variety of analytical applications due to their simplicity, selectivity, and low cost. Recent developments in materials science and digital fabrication have opened new opportunities for redesigning ISEs using modern manufacturing techniques. Here, we present a new application of 3D printing for fabricating potassium-selective electrodes using a simplified membrane composition. The 3D printing cocktail was prepared by mixing potassium tetraphenylborate, silver sulfide or graphite, and industrial ABS (acrylonitrile Butadiene Styrene) polymer. Membranes were tested both without and with the addition of ZnO nanoparticles. Incorporation of ZnO NPs significantly enhanced the electrode slope, while graphite-based membranes exhibited faster response, with potential stabilizing within 3–7 s across a concentration range of 4.88 × 10−5 mol L−1 to 1.00 × 10−2 mol L−1. The optimized 3D printed membrane containing 0.6% ZnO NPs showed near-Nernstian behaviour (slope: 59.178 mV per decade and R2 = 0.9989), a limit of detection of 2.06 × 10−5 mol L−1 and high selectivity against common interfering ions. These results demonstrate that 3D printing combined with a suitable membrane composition and nanoparticle incorporation provides a versatile platform for rapid, reproducible, and high-performance potassium ISEs.