A comparison study of macrocyclic hosts functionalized reduced graphene oxide for electrochemical recognition of tadalafil

The present work described the comparison of beta-cyclodextrin (beta-CD) and p-sulfonated calix[6]arene (SCX6) functionalized reduced graphene oxide (RGO) for recognition of tadalafil. In this study, tadalafil and two macrocycles (beta-CD and SCX6) were selected as the guest and host molecules, respectively. The inclusion complexes of (beta-CD/tadalafil and SCX6/tadalafil were studied by UV spectroscopy and molecular simulation calculations, proving the higher supermolecular recognition capability of SCX6 than beta-CD towards tadalafil. The beta-CD@RGO and SCX6@RGO composites were prepared by a wet-chemical route. The obtained composites were characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, atomic force microscopy, and zeta potential. The SCX6@RGO showed a higher electrochemical response than beta-CD@RGO, which was caused by the higher recognition capability of SCX6 than beta-CD. By combining the merits of SCX6 and the RGO, a sensitive electrochemical sensing platform was developed based on the SCX6@RGO nanohybrids. A linear response range of 0.1-50 mu M and 50-1000 mu M for tadalafil with a low detection limit of 0.045 mu M (S/N=3) was obtained by using this method. The constructed sensing platform was successfully used to determine tadalafil in herbal sexual health products and spiked human serum samples, suggesting its promising analytical applications for the trace level determination of tadalafil. (C) 2016 Elsevier B.V. All rights reserved.