Ultrasensitive and rapid colorimetric detection of urotropin boosted by effective electrostatic probing and...

Leakage and contamination of hazardous chemical substances have been widely recognized as the critical issue in ensuring human health, maintaining environmental sustainability, and safeguarding public security. Urotropin as a crucial raw material in industrial holds a potential threat to aquatic/atmospheric environment with refractory degradation problem, hence, there remains a severe challenge to effectively and on-site monitor urotropin. Here, a general design with all-in-one strategy was presented, in which a highly integrated "pocket sensing chip" combining a sampling unit and a detecting unit together endows a rapid and ultrasensitive colorimetric detection without dead-zone towards urotropin. By loading fast blue B as sensing reagent in the detecting unit, a moderate and sensitive detection towards urotropin via electrostatic interaction was achieved with detection limits of 9 μM for liquid and 17.19 ng for particulates. Furthermore, an expandable sensing chip for the purpose of simultaneously screening on multi-target exhibited remarkable applicability for examining suspicious objects with all sorts of surface in real scenes, being unacted on environmental complexity. We expect this design would provide a universal strategy and the high referential value to propel the development of handy and portable sensing device to efficiently screen the environmental relevant critical substance on-site.