Potato starch as a highly enantioselective system for temperature-dependent electrochemical recognition of tryptophan isomers

A simple but highly enantioselective system based on potato starch (PS) modified electrode was developed for electrochemical recognition of tryptophan (Trp) isomers. Due to favorability of host–guest interactions between PS and D-Trp, PS preferably combined with D-Trp compared with L-Trp, resulting in larger amount of L-Trp penetrating through the left-handed double helices of PS to the electrode surface than D-Trp. And therefore, successful recognition of Trp isomers was achieved at the PS-based electrode. The PS-based chiral recognition was temperature dependent, which was attributed to the significant influence of temperature on the H-bonds between PS and the guest molecules. The recognition efficiency was remarkably decreased after hydroxypropyl groups were introduced to PS, and the decreased recognition efficiency at the hydroxypropyl PS (H-PS) might be due to the extra steric hindrance .