One-step synthesis of a pH switched pyrene-based fluorescent probe for ratiometric detection of HS- in real water samples

Kuppan Magesh; Sukhvant Singh; Shu Pao Wu; Sivan Velmathi

doi:10.1039/d3ay00987d

One-step synthesis of a pH switched pyrene-based fluorescent probe for ratiometric detection of HS^- in real water samples

Anal Methods. 2023 Aug 24;15(33):4159-4167. doi: 10.1039/d3ay00987d.

Authors

Kuppan Magesh¹, Sukhvant Singh¹, Shu Pao Wu², Sivan Velmathi¹

Affiliations

¹ Organic and Polymer Synthesis Laboratory, Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, India. velmathis@nitt.edu.
² Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu 30010, Republic of China.

PMID: 37577757
DOI: 10.1039/d3ay00987d

Abstract

Only a few probes are suited for highly acidic environments and sensitive to pH values below 4. Thus, finding a solution for detecting strong acidic (pH value below 2) conditions is still challenging. Herein, we constructed and created a pH-switched fluorescent probe based on pyrene and a heteroatom containing pyridine unit. When exposed to acidic environments (pH 2.0), the probe's fluorescence redshifted with distinct colour and fluorescence changes owing to protonation on the nitrogen atom containing pyridine moiety, which could be deprotonated by HS^- selectively compared to other competing analytes. Pyr can detect HS^- with a rapid response within 5 s and showed very good quantum yield under acidic environments. The sensing mechanism was confirmed by Density Functional Theory (DFT) studies using the B3LYP and 6-31G+ (d) basis sets. Furthermore, the probe was utilized to monitor HS^- in actual water samples and identify H₂S gas by a simple paper strip test.