Accurate Identification of MDMB-Type Synthetic Cannabinoids through Design of Dual Excited-State Intramolecular Proton Transfer Site Probe and Deep-Learning

Synthetic cannabinoids, a novel class of highly toxic psychoactive substances with various disguised forms, have posed significant risks to public safety, and their weak reactivity presents a substantial challenge for swift and accurate analysis. In this work, we develop an optical probe equipped with dual excited-state intramolecular proton transfer (ESIPT) sites that inhibit the intramolecular proton transfer through hydrogen bonding, facilitating the specific detection of MDMB-type synthetic cannabinoids. The probe can sensitively detect the MDMB-type synthetic cannabinoids at 1.8 × 10-3 mg/mL, specifically recognizing them among 20 potential interferents with a rapid fluorescence response within 1.2 s, leading to the development of a portable, user-friendly sensor for a swift and precise analysis of these compounds in complex scenarios. Furthermore, this study combines a portable sensing chip with an advanced convolutional algorithm for image processing, enabling precise differentiation among six MDMB-type synthetic cannabinoid variants. This study successfully detected the target substance by creating a dual ESIPT optical probe, thereby offering a novel approach to detect psychoactive substances with limited reactivity.