Colorimetric-fluorescent dual-mode sensing of peroxide explosives based on inner filter effect with boosted sensitivity and selectivity

Abstract

1 The carbon dots were used as the fluorophore and combined with titanyl sulfate for the colorimetric and fluorescent dual-mode sensing of peroxide-based explosives based on Inner Filter Effect. 2 The carbon dots/titanyl sulfate sensing system was endowed with the combined merits of the good selectivity of the colorimetric reaction and the enhanced sensitivity of the fluorescent method. 3 The carbon dots/titanyl sulfate sensing system incorporated with hydrogel was applied for the on-site colorimetric and fluorescent dual-mode visual detection of peroxides, including peroxide-based explosives, in liquid, solid and vapor phases. As one of the most popular improvised explosives, the detection of peroxide-based explosives (PBEs) is of great urgency for reducing or potentially stemming explosive-related terrorist attacks. However, few of the currently developed optical sensor focus on the direct detection of PBEs. Here, a general design strategy for the direct, sensitive and specific coloerimetric and fluorescent dual-mode sensing of peroxides was proposed by triggering the Inner Filter Effect (IFE) in the carbon dots/titanyl sulfate (CDs/TiOSO 4 ) sensing system. The colorimetric and fluorescent limits of detection (LODs) of the proposed CDs/TiOSO 4 sensing system towards hydrogen peroxide as representative were calculated to be 31.3 μM and 0.2 μM, respectively. Further practical sensing performances of the sensing system with incorperation of hydrogel platform demonstrated the universality for the detection of various PBEs in liquid, solid and even vapor phases with a LOD of 0.15 ppb for vapor sensing. This study provides an inspirable strategy for designing IFE-based dual-mode sensors for on-site visual detection. .