A Pyrazoline-Based Fluorescent Sensor for Picric Acid Detection in Aqueous Media: Experimental and DFT Insights

The present research work describes the development of a pyrazoline-based fluorescence sensor 3-[(5R)-5-(1-benzothiophen-3 - yl)-1-phenyl-4,5-dihydro-1H-pyrazol-3 - yl] phenol (BTP) for reliable identification of picric acid (PA) in aqueous environments. The sensor's efficiency was evaluated based on its linear range (0 to 10 µM) and detection limit (0.991 µM), which demonstrate a greater sensitivity across various matrices, including river, tap, and bottled water. BTP exhibited a higher quenching efficiency of 75.12% for picric acid (PA) as compared to other nitroaromatics. DFT studies provided the theoretical information of the BTP-PA complex. The investigation of the FMOs and quenching efficiency indicates that the BTP-PA interaction occurs upon an electron transfer mechanism.