A two-in-one sensing solvent for green extraction and analysis of N-oxide based explosives

The analysis of N-oxide based explosives is beneficial to avoiding explosive risk and toxic hazard to the public. Nowadays, multifunctional sensors are scarce for green extraction and analysis of N-oxide based explosives. Herein, we have designed and developed two-in-one sensing solvents (DSMs) based on deep eutectic solvents with dual functions of both extraction and detection toward N-oxide based explosives. Besides, as an extraction solvent, DSM-3 based choline chloride and urea also can detect N-oxide based explosives via color change from yellow to red. The sensing mechanism of DSM-3 toward 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) as a prototype of N-oxide-based explosives has been fully investigated by experimental analysis and theoretical calculations. The proposed mechanism is based on the formation of H-bonding complexes between urea of DSM-3 and N-oxide group of LLM-105, which induces the charge transfer from urea to LLM-105. Further, this assay exhibits high selectivity, sensitivity and good visualization for the determination of LLM-105. Therefore, our study provides novel two-in-one sensing solvent for green, convenient and on-site detection of N-oxide based explosives.