An Ultra-Sensitive Fluorescent Probe Based on Hybridized Local and Charge-Transfer Materials for Quantitative Detection of Propanol Isomers

Isopropanol has been widely applied in various fields as an important chemical solvent, which is produced by direct hydration of propylene accompanied with the byproduct of n-propanol. Herein, an ultra-sensitive fluorescent probe of TPA-9AC, based on a non-equivalent hybridized local and charge-transfer (HLCT) material, is designed and synthesized to quantitatively detect the percentage of n-propanol in propanol isomers. Owing to the stronger electron acceptor ability of n-propanol, the excited state of probe transfers from highly emissive HLCT state to non-emissive charge-transfer state, resulting in the substantial fluorescence quenching. The low limit of detection (LOD) is achieved as sensitive as 0.02% v/v of n-propanol in isopropanol. This contribution demonstrates a new approach to distinguish propanol isomers and an effective strategy for designing real-time fluorescent sensors with high performances.