# Selective detection of arsenite in alkaline media using a yolk-shell (Ce/Fe) terephthalate/organoclay framework stripping voltammetric sensor

## TL;DR

A new sensor detects arsenite in water and soil with high sensitivity and without sample preparation, aiding environmental monitoring.

## Contribution

A novel yolk-shell nanocomposite sensor for selective arsenite detection in alkaline conditions is developed.

## Key findings

- The sensor detects arsenite with a detection limit of 0.00045 ppb and a sensitivity of 436.68 µA/ppb.
- The sensor shows high selectivity for arsenite in the presence of other heavy metals in strongly basic media.
- The nanocomposite material provides abundant active sites, enhancing sensor performance and sustainability.

## Abstract

To address environmental and health challenges while promoting sustainable clean water and soil, a highly sensitive graphite paste sensor incorporating a nanocomposite material has been developed. This sensor utilizes a yolk-shell (Ce/Fe) terephthalate (Ce/Fe-Tph.) framework intercalated with organoclay (MMtD2000) nanolayers, forming a Ce/Fe-Tph./MMtD2000 framework nanocomposite for the detection of arsenite (As3+) ions. The yolk-shell Ce/Fe-Tph./MMtD2000 framework nanocomposite was synthesized via a solvothermal method, yielding excellent crystallinity and a high surface area of 1054 m².g− ¹. This enhanced surface area provides abundant active sites, thereby improving sensor performance and supporting sustainable environmental monitoring. The 1.0% (Ce/Fe-Tph./MMtD2000) modified graphite paste sensor (MGPS) exhibited enhanced electrocatalytic activity and adsorption performance. It achieved a broad detection range of 0.0015–0.0749 ppb (0.02–1.0 nM) and an ultralow detection limit of 0.00045 ppb (0.006 nM) for As3+ ions using square wave adsorptive cathodic stripping voltammetry (SW-AdCSV), with a sensitivity of 436.68 µA/ppb (32.7 µA.nM− 1). The sensor also demonstrated high accuracy, reproducibility, and stability, along with exceptional selectivity for the detection of As3+ ions in the presence of other heavy metal ions, without interference in strongly basic media. This sensor provides a simple, direct method for detecting As3+ ions in environmental samples including real water and soil matrices, without requiring sample pretreatment. Its capabilities align with sustainable development goals by advancing environmental monitoring.

The online version contains supplementary material available at 10.1007/s00604-025-07782-x.