Potentiometric Sensing of Chiral Amino Acids

Recognition of enantiomers of amino acids was achieved with potentiometric measurements using chiral sensors constructed by a surface imprinting technique. The sensors exhibited recognition properties toward one isomer of racemic N -carbobenzoxy-aspartic acids (N-CBZ-Asp) without any preseparation processes. The sensors translated the enantioselective recognition event into a potential change by detecting optically active N-CBZ-Asp in a concentration range of 5.0 × 10 - 6 −1.2 × 10 - 2 M. The enantiomeric selectivity coefficients of the sensors for the counter isomers were in the range of 4.0 × 10 - 3 −9.0 × 10 - 3 . The sensitivity of these sensors is assigned to the specific surface modification of the electrodes resulting in chiral recognition and to the coupled transduction activity of the sensor.