# Construction of a Fluorescence‐Based Logic Gate Seeing the Effect of Perchlorate Ions on Hemicyanine Dye–β‐Cyclodextrin Complexes to Certify Safe Drinking Water

## TL;DR

A new method uses fluorescence-based logic gates to detect perchlorate ions in water, helping ensure drinking water safety.

## Contribution

A novel fluorescence-based logic gate system is developed to detect perchlorate ion toxicity in water.

## Key findings

- DASPC22 fluorescence increases with β-CD and low ClO4− concentrations due to hydrogen bonding.
- A YES logic gate is constructed to quantify perchlorate toxicity in water.
- AND and INHIBIT logic gates are developed using different ClO4− concentrations.

## Abstract

Perchlorate ions (ClO4
−) are prevalent contaminants in the surface, and drinking water that disrupt thyroid function by competitively inhibiting the sodium‐iodide symporter (NIS), posing significant health risks. Here, fluorescence‐based logic gates have been constructed by leveraging the binding interactions between a hemicyanine dye, 4‐[4‐(dimethylamino)‐styryl]‐1‐docosylpyridinium bromide (DASPC22) and β‐cyclodextrin (β‐CD) that could be useful to know whether ClO4
− ions in water are within the toxicity range or not. In aqueous media, DASPC22 forms nonfluorescent H‐aggregates, but fluorescence is enhanced upon forming host‐guest inclusion complexes with β‐CD. At low ClO4
− ions concentrations, fluorescence intensity further increases due to enhanced complex stability through hydrogen bonding. ONIOM‐based quantum chemical calculations have supported this phenomenon. The enhancement of fluorescence intensity of DASPC22 in the presence of β‐CD and a low concentration of ClO4
− ions leads to the construction of a YES logic gate that would enable one to quantify ClO4
− ions’ toxicity range in water. Dual‐input‐single‐output AND and INHIBIT logic gates with low and high concentrations of ClO4
− ions, respectively, have also been constructed. The present system could be useful in addressing safety concerns related to perchlorate contamination of water.

A method to detect perchlorate ions and certify safe drinking water by constructing a fluorescence‐based logic gate considering the binding of a hemicyanine dye with β‐CD is presented.© 2025 WILEY‐VCH GmbH