Enhanced detection of explosives: A novel approach using poly(2-oxazoline)s-based molecularly imprinted polymers combined with ambient mass spectrometry

Detecting explosives in the environment is essential due to their toxic and mutagenic effects on living organisms. This study presents a novel method for the selective detection and quantification of explosives, including picric acid, 1,3,5-trinitro-1,3,5-triazinane (Research Department Explosive, RDX), and pentaerythritol tetranitrate (PETN), using molecularly imprinted polymers (MIPs) coupled with flowing atmospheric pressure afterglow mass spectrometry (FAPA-MS). MIPs were synthesized via a molecular imprinting process with short-chain poly(2-methoxycarbonylpropyl-2-oxazoline) as the pre-polymer, yielding materials with high affinity for the target compounds. The method achieved detection limits as low as 0.01 µM, representing improvements of two orders of magnitude for picric acid and PETN and one order for RDX compared to direct solution analysis. Spiked river water samples showed high recovery rates, within 8.2 % of true values, confirming the method’s accuracy. Strong linearity with R² higher than 0.99 and very good precision with RSD not exceeding 8.9 % further validated the system. This approach demonstrates the potential of poly(2-oxazoline)-based MIPs in conjunction with ambient MS for sensitive, accurate, and reliable detection of explosives, offering significant applications in environmental monitoring and screening for illegal manufacturing sites.