Paraoxon is a highly toxic substance that's often found in the environment. It's crucial to have a reliable way to detect it. This is where a new method comes in. It uses a special hydrogel made from cerium and carbon dots. This hydrogel has two key abilities: it can act like an enzyme that breaks down certain substances, and it can also amplify fluorescence signals.

The hydrogel is designed to work with a compound called 5, 7-dimethoxycoumarin. When paraoxon is present, the hydrogel breaks it down into a yellow substance called 4-nitrophenol. This change in color allows for colorimetric detection of paraoxon, with a detection limit of 1. 2 μM. At the same time, the formation of a stable complex involving 5, 7-dimethoxycoumarin, 4-nitrophenol, and the hydrogel leads to a significant increase in fluorescence quenching. This makes the detection of paraoxon even more sensitive, with a detection limit of 15. 4 nM.

This dual-mode detection method is a big improvement over single-signal approaches. It works under the same conditions for both colorimetric and fluorescence detection, and it expands the detection range by three orders of magnitude. This means it can detect paraoxon in a much wider range of concentrations.

To make this method even more practical, a portable platform was developed. This platform uses a smartphone to visually quantify paraoxon levels in vegetables like cauliflower and Chinese cabbage. The results were impressive, with recoveries ranging from 99% to 114% and relative standard deviations below 5%. This shows that the method is both accurate and reliable.

This new approach sets a new standard for designing multimode biosensors. It combines rational nanozyme engineering with synergistic signal amplification strategies. This makes it a powerful tool for detecting paraoxon and potentially other harmful substances in the environment.

Detecting Danger: A Smart Way to Spot Paraoxon

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