Computational Evaluation of the Use of Fluorescein Isothiocyanate as a Preliminary Test for Amphetamines and Cathinones

The rise of new psychoactive substances (NPS) challenges traditional drug detection, especially in initial analyses. This research investigates fluorescein isothiocyanate (FITC) as a potential colorimetric reagent for detecting amphetamines and related cathinones through computational and mechanistic methods. Forty-two amphetamine-type stimulants were examined using density functional theory (DFT) and UV-vis spectra via TD-DFT. Results showed FITC interacts specifically with primary and secondary amines, causing lower excitation energies and spectral shifts into the visible spectrum. However, statistical testsPearson's correlation, PCA, and ANOVAindicate that this chromophore has limited ability to distinguish between amphetamines and cathinones. Hence, FITC-based tests might be useful as part of a series of presumptive assays but are not suitable as a sole method. Furthermore, the study highlights how in silico methods can effectively evaluate new reagents for forensic purposes, providing faster and more cost-efficient alternatives to experimental testing.