Complexation of cathinones by 4-tert-butylcalix[4]arene tetra-acetate as a possible technique for forensic analysis

Abstract

Cathinone derivatives are new psychoactive substance(s) (NPSs) with amphetamine-like effects and currently represent a great problem for public health. For this reason it is necessary to develop new sensitive, selective fast and inexpensive methods for large-scale screening of NPSs. The purpose of this study was to evaluate the capabilities of 4-tert-butylcalix[4]arene tetra-acetate as a receptor of potentiometric sensor to recognize NPSs based on cathinone derivatives and one aminoindane for comparison. Potentiometry was used to determine the selectivity of a 4-tert-butylcalix[4]arene tetra-acetate towards cathinone derivatives. Density functional theory (DFT) computations and nuclear magnetic resonance (NMR) titration were used to explain the binding modes of the calix[4]arene derivative towards selected NPSs. The basic binding mode of the calix[4]arene derivative for NPSs, namely a hydrogen bonding towards the NH group, was confirmed using DFT calculations and NMR titration. Importantly, the calix[4]arene derivative as the receptor of the potentiometric sensor provides (1) discrimination between cathinone derivatives themselves and cathinones from aminoindane as well as the (2) possibility of detection of buphedrone in samples containing the mixture of the different NPSs including cathinones (Sr ≤ 0.11). A potentiometric sensor based on calix[4]arene derivative provided a rapid and perspective technique for the detection of cathinone derivatives. These results show that potentiometric sensors can become promising future tools for NPSs detection.