Next-Generation Rhodamine-Based Fluorescent Sensors for Identification of Poisonous Chemical Weapons: Recent Progress in Nerve Agents and Phosgene Detection

The detection of nerve agents has gained critical global importance following incidents such as the 1995 Tokyo subway sarin attack and more recent events in Syria. These highly toxic organophosphates including tabun, sarin, soman, and cyclosarin irreversibly inhibit acetylcholinesterase, causing rapid paralysis and death even at microgram doses. Phosgene, another lethal chemical threat, poses additional risks in both industrial and security contexts. While current detection technologies such as biosensors, electrochemical devices, and mass spectrometry provide valuable capabilities, they often lack portability, rapid response, or operational simplicity. Fluorescent chemosensors, particularly rhodamine-based systems, have emerged as promising alternatives due to their high sensitivity, fast response, and potential for real-time, visual detection. The spirolactam-to-rhodamine transformation offers a robust platform for selective detection of nerve agents and simulants like diethyl chlorophosphate. This short review summarizes recent advances in rhodamine-based chemosensors for nerve agents and phosgene, and discusses future prospects including integration with portable devices, dual-mode detection, and sustainable sensor designs.