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.