Preparation of molecularly imprinted silica-wrapped ionic liquid-regulated carbon quantum dots and its application in the electroluminescence and fluorescence dual-mode detection of ochratoxin A

Abstract

Ochratoxin A (OTA) is a highly harmful substance, and its sensitive and accurate detection in foods is quite important. Herein, an electrochemiluminescence (ECL)/fluorescence dual-mode sensor based on surface molecular imprinting on silica-wrapped ionic liquid-modified carbon dots (IL-CDs) is fabricated for OTA detection. In this case, the molecularly imprinted layer is prepared by chemical polymerization, and it not only acts as an identification unit but also protects the CDs. The ionic liquid 1-aminopropyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide is introduced in the synthesis of CDs as a surface modifier, which significantly enhances the density of secondary amine on the surface of CDs and the ECL intensity. The obtained nanoparticles show very low cytotoxicity and can produce strong ECL signal in the presence of coreactant tripropylamine and fluorescence signal under 360 nm light excitation. When the system is used for the detection of OTA, it displays high sensitivity, reproducibility and stability. Through dual-mode correction, the relative standard deviation decreases obviously and the recoveries become more satisfactory as 97.9∼102 % in detecting OTA in white wine, beer and peanut oil samples. Accordingly, this work provides a promising option for the accurate and rapid detection of OTA.