Enantioanalysis of R-deprenyl based on its molecular interaction with C70 fullerenes

Abstract

Two enantioselective, potentiometric membrane electrodes based on [5,6]fullerene-C(70) (1) and diethyl (1,2-methanofullerene C(70))-71-71-dicarboxylate (2) immobilized in carbon paste, were designed for the enantioanalysis of R-deprenyl. The electrodes exhibited near-Nernstian slopes: 57.90 (1) and 59.00mV/decade of concentration (2), respectively with low limits of detection 5.9x10(-11) (1) and 9.6x10(-11)mol/L (2), respectively. The linear concentration ranges are between 10(-10) and 10(-4)mol/L (1) and between 10(-9) and 10(-4)mol/L (2), respectively. The different characteristics involved in the molecular interaction between R-deprenyl and C(70) fullerenes were explained, namely (i) the stability of each molecule and (ii) the explanation of the molecular mechanism of interaction, using restricted Hartree-Fock theory, 3-21G(*) RHF-basis set. Furthermore, two intermolecular forces of interactions confer the stability of the electrodes; electrostatic interaction and moderate hydrogen bond interaction. Stability and feasibility of all the generated structures involved in this analysis were supported by their respective fundamental frequencies and energy minima. R-deprenyl can be recovered with average recoveries higher than 99.10% (RSD<0.03%) from synthetic mixtures between R- and S-deprenyl. The high selectivity and enantioselectivity made possible the enantioanalysis of R-deprenyl in its pharmaceutical formulations.