Electrochemically oxidized 15-crown-5 substituted thiophene and host-guest interaction with new psychoactive substances

Abstract The aim of this work is to develop an impedimetric sensor using the principle of host-guest interaction for the detection of new psychoactive substances (NPSs). Synthesized 4′-(N-3-thiophenecarboxamido)benzo-15-crown-5 (TH3CA4AB15C5) was electrochemically deposited on the surface of a platinum disc electrode using cyclic voltammetry. Spectroscopic (infrared and NMR spectroscopy) and electrochemical impedance spectroscopy (EIS) studies were applied to confirm the structure of the polymeric film deposited onto the electrode surface and to evaluate its affinity towards 2-aminoindane (AI), 2-(methylamino)-1-phenylbutan-1-one (buphedrone, MABP) and 3′,4′-methylenedioxy-α-pyrrolidinopropiophenone (MDPPP). These studies showed that the ease of formation hydrogen bonds between the product of electrochemical oxidation (TH3CA4AB15C5) and the above-mentioned analytes is the dominant factor for obtaining a useful analytical signal. The changes in the resistance to charge transfer obtained during the EIS measurements allowed: i) to separately measure both the synthetic cathinones (MABP, MDPPP) and AI in the concentration range 1.99 10 –5 – 1.22 10– 3 M; ii) to quantify AI at levels of (1.6 – 3.0) x 10–4 M in the presence of various representatives from the NPS family.