The highly sensitive detection of improvised explosives is crucial for ensuring national security and public safety, yet it remains a significant challenge in analytical detection.

Hydrogen peroxide (H₂O₂), the primary precursor for various improvised explosives—such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), and hexamethylene triperoxide diamine (HMTD)—requires ultrasensitive detection to meet practical demands. To tackle this issue, researchers from the Xinjiang Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences, have proposed a synergistic strategy to enhance the sensitivity of H₂O₂ detection by using π-conjugated bridge regulation and nanocellulose signal enrichment.

The researchers designed and synthesized three naphthalimide-based probes (MOHB-IMTP, MOHB-IMP, and MOHB-IMF) with thiophene, benzene ring, and furan as the bridging elements and boric acid as the recognition site. Among these probes, the MOHB-IMTP showed the highest reactivity. When detecting H₂O₂, the probe undergoes oxidation of its boric acid, leading to the cleavage of the π-conjugated bridge's C=N bond. This results in a ratiometric fluorescent change from light blue to yellow-green. The MOHB-IMTP probe exhibited superior sensing performance for H₂O₂, featuring a lower limit of detection (LOD) of 38.5 nM and excellent selectivity, even in the presence of 22 potential interferents.

Moreover, further signal enrichment achieved an even better LOD of 4.0 nM through the use of a MOHB-IMTP/cellulose colloidal probe, which integrated into a portable automated monitoring device. The combined strategies of π-conjugated bridge regulation and nanocellulose signal enrichment are anticipated to inspire new designs for highly sensitive sensing materials targeting trace chemical substances.

This research was published in Analytical Chemistry and was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Xinjiang, among other sources.