Selective Quantification of Carnitine Enantiomers Using Chiral Cysteine-Capped CdSe(ZnS) Quantum Dots

We report the first observation of selective and specific recognition of chiral L-cysteine (L-Cys)- or D-cysteine (D-Cys)-capped CdSe(ZnS) quantum dots (QDs) with carnitine enantiomers in aqueous solution. The intensity fluorescence of L-Cys-capped QDs decay in the presence of D-carnitine but are not affected by L-carnitine. On the other hand, the fluorescence of D-Cys-capped QDs was only affected by L-carnitine. The applicability of chiral Cys-capped QDs for the analysis of chiral mixtures on enantiomers has been demonstrated for 1:100 mixtures, and the results that were obtained had high precision (<2.3%) and low error (<2.7%).