Coumarin 153 Fluorescent Probe for Highly Sensitive and Selective Detection of 2-Nitrodiphenylamine.

Abstract

During propellant storage, the release of nitrogen oxides consumes the stabilizer 2-nitrodiphenylamine (2-NDPA), whose residual content serves as a key indicator for assessing ammunition aging and safe service life. Conventional detection methods, predominantly based on chromatography, are hindered by high costs, complex operation, and unsuitability for on-site analysis. Herein, we report a rapid detection method using coumarin 153 (C153) as a single fluorescent signal unit. Experimental results show that the fluorescence intensity of C153 at 527 nm decreases linearly upon addition of 2-NDPA, with a rapid response (response time < 5 s) and a detection limit of 0.60 µmol·L^-1. Selectivity tests against 19 structurally analogous stabilizers and their derivatives confirm the high specificity of this probe for 2-NDPA. Mechanistic investigations, combining fluorescence lifetime measurements and spectral overlap analysis, attribute the quenching to the inner filter effect. Furthermore, the practical utility of this method is validated through both leachate and vapor-phase tests on aged propellant samples, demonstrating that the fluorescence quenching response correlates inversely with the extent of aging. This strategy offers a cost-effective and operationally simple alternative for monitoring propellant stabilizers.