From smart drugs to smartphone: A colorimetric spot test for the analysis of the synthetic cannabinoid AB-001

Abstract

The use of synthetic cannabinoids is an emerging problem in contemporary society, and the detection techniques currently used do not meet the requirements of a drug test. We report herein an inexpensive, in situ method for the detection of the synthetic cannabinoid AB-001 in herbal samples. The method exploits a colorimetric kit consisting in a 96 plate well containing a bench stable modified Ehrlich reagent adsorbed on silica. The colour derived by the interaction of AB-001 with the detection matrix is read on a RGB (Red, Green, and Blue) base by using the camera of a smartphone, thus making the method accessible to everyone.A calibration curve of the analyte in the range 1–200 μg was realized, with a MQL (method quantitation limit) of 1 μg and positive recovery tests from samples of tobacco and damiana spiked with different amounts of AB-001. The method presents selectivity for AB-001 with respect to other indole-based cannabinoids (e.g. JWH-018, JWH-302, whose response is ca 5% of the one produced by the same concentration of AB-001) and other common drugs (e.g. acetaminophen, ascorbic acid, bromazepam, fluoxetine), these last not interfering up to a 100:1 drug:AB-001 ratio.This new colorimetric approach would be considered a category C screening test, and therefore recommended as part of a comprehensive analytical scheme for the identification of AB-001.