Amperometric detection of amino acids in a flow-injection system with a nickel(II)-modified electrode with an Eastman-AQ polymer film
Authors:
Anhua Liu and Erkang Wang
Affiliation:
Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Scineces, Changchun, Jilin 130022 China
Abstract:
Amperometic flow measurements were made at +0.55 V (vs. Ag/AgCl) in 0.1 mol l−1 KOH electrolyte with an Ni(II) chemically modified electrode (CME) with an Eastman-AQ polymer film. The use and characteristics of a Ni(II)-containing crystalline and polymer-modified electrode obtained by a double coating step as a detector for amino acids in a flow-injection system using reversed-phase liquid chromatography are described. The detection of these analytes is based on the higher oxidation state of nickel (NiOOH) controlled by the applied potential. The electroanalytical parameters and the detection current for a series of amines and amino acids were investigated. The use of such a CME in the flow-injection technique was found to be suitable in a solution at low pH. The linear range for glycine is 5 × 10−6-0.1 mol l−1 with a detection limit of 1.0×10−6 mol l−1. A 1 × 10−4 mol l−1 mixture of serine and tyrosine was also detected after separation on an Nucleosil C18 column.