Enantiodiscrimination ability of different inherently chiral selectors with DOPA and other chiral probes of pharmaceutical interest

Chiral electroanalysis could be regarded as the highest recognition degree in electro-chemical sensing, implying the ability to discriminate between specular images of a giv-en electroactive molecule, in terms of peak potential difference. A ground-breaking strategy was recently proposed by our research group, based on the use of “inherently chiral” molecular selectors, where the stereogenic element responsible for chirality coin-cides with the functional group responsible for the material specific properties [1,2]. Enantiodiscrimination is of course of high interest in the pharmaceutical field. A collec-tion of tests are here presented, focusing on L- and D-3,4-dihydroxyphenylalanine, (L- and D-DOPA, L-DOPA being commonly employed to treat akinesia in Parkinson's dis-ease), including a test in real matrix (i.e. as the main component of the Madopar® drug in combination with benserazide) [4]. In particular, cyclic voltammetry (CV) tests were performed at interphases with implementation of inherent chirality selectors according to two strategies: i) use of electrode surfaces modified with electrodeposited heterocycle-based inherently chiral oligomer films (with different stereogenic elements, C2 axis vs helix) [3,4,5]; ii) use of enantiopure chiral media of high intrinsic order based on inher-ently chiral molecular additives dissolved in achiral commercial ionic liquids [6]. In all cases neat enantiodiscrimination, in terms of fair to large peak potential differences for the DOPA enantiomers, specular by inversion of selector configuration, was observed, confirming the general validity of this strategy. The novel approach looks of wide applicability also in terms of chiral probes, since promising results were also obtained testing inherently chiral selectors for enantio-discrimination of other pharmaceutically relevant chiral molecules of different chemical nature and bulkiness, like tyrosine, ofloxacin, tryptophan and naproxene [3,4,7].