# Schiff Base–Derived Colorimetric Chemosensor for Fe3+ Detection: Synthesis, Mechanistic Insights, and Real‐World Applications in Water Quality Monitoring

## TL;DR

A new color-changing sensor was developed to detect Fe3+ in water, offering a simple and effective method for water quality monitoring.

## Contribution

A novel Schiff base chemosensor with high selectivity and practical on-site detection capabilities for Fe3+.

## Key findings

- The sensor shows a visible color change from yellow to black upon Fe3+ detection.
- It achieves a low detection limit of 3.71 μM in solution and 50.7 μM on paper strips.
- The sensor demonstrated high recovery rates in real water samples, confirming its practical utility.

## Abstract

A Schiff base colorimetric chemosensor (H2L), synthesized from 2‐hydroxy‐1‐naphthaldehyde and anthranilic acid, was developed for selective Fe3+ detection. In a DMF:H2O (9:1, v/v) medium, H2L exhibited a distinct and selective response to Fe3+ among common competing cations, producing a visible color change from yellow to black and a new broad absorption band at 504 nm. Job’s plot indicated a 1:1 binding stoichiometry, and the association constant was 2.87 × 104 M−1. The sensor showed a low detection limit of 3.71 μM by UV–Vis titration, and its practical applicability was validated by spike–recovery analysis in real water samples (recoveries 91.04%–100.94%). A paper‐strip assay enabled rapid on‐site screening with smartphone image analysis, achieving an LOD of 50.7 μM. These results highlight H2L as a simple and effective platform for Fe3+ monitoring in water‐relevant matrices.