Use of some amino acid potentiometric biosensors as detectors in ion chromatography

In this study, composite amino acid-sensitive potentiometric biosensors in microsizes were prepared and used as detectors in ion chromatography (IC). First, ammonium-selective electrodes were prepared, and their potentiometric behavior was tested. Then, the L-amino acid oxidase (L-AAO) enzyme was attached to the surface of the ammonium-selective potentiometric electrodes with glutaraldehyde crosslinker. The potentiometric behavior of the prepared biosensors against different L-amino acids was investigated. The biosensors exhibited ideal potentiometric responses to some of the L-amino acids. Biosensors with the ideal potentiometric behavior were placed in the moving medium flow cell together with the Ag/AgCl reference electrode. This flow cell was placed at the exit of the column in the ion chromatographic system, allowing it to function as a detector. The chromatograms were obtained by injecting free amino acids into the prepared chromatography-potentiometry hybrid system. The obtained results showed that the prepared biosensors can be used as detectors in chromatography and as detectors in the determination of free amino acids.