Enhanced Detection of narcotics Using Vapor-Phase Analysis from Rapid Drug Test Kits: Paving the Way for Breath-Based Diagnostics

Abstract

With the rapid rise of drug crimes in South Korea and the emergence of over 900 new psychoactive substances (NPS), conventional forensic analysis has reached its practical limits. This study introduces a portable vapor-phase drug detection kit integrated with a colorimetric metal–organic framework (MOF) sensor array and AI-assisted imaging analysis for rapid, on-site screening. Unlike conventional liquid-based methods that require laboratory instrumentation and long processing times, the proposed platform directly detects vaporized drug particles in real time without complex preparation. The MOF array exhibited distinct and reproducible color transitions across 54 tested drugs, demonstrating excellent sensitivity and durability. Quantitative RGB pattern analysis revealed group-specific optical responses: Amphetamine-, Cathinone-, MDxx-, and Benzofuran-class compounds shared a characteristic decrease in G values and increase in B values, while non-phenethylamine and heterocyclic tropane groups displayed unique, independent RGB patterns. These findings indicate that phenethylamine-type structures exhibit consistent chromatic signatures, enabling structural classification through colorimetric data. This technology provides a field-deployable, non-destructive, and customizable drug detection platform for forensic and law-enforcement applications, with future potential in breath-based diagnostics, environmental monitoring, and food-safety testing.