Chemiluminescence flow biosensor for determination of total D-amino acid in serum with immobilized reagents

A flow-injection chemiluminescence (CL) biosensor for the determination of total D-amino acid is described in this paper. D-amino acid oxidase was immobilized onto amine-modified silicagel via glutaraldehyde activation and packed in a column. The other analytical reagents, including luminol and ferricyanide, were electrostatically co-immobilized on an anion-exchange column. D-amino acid was sensed by the CL reaction between hydrogen peroxide produced from the enzyme column and luminol and ferricyanide, which were eluted from the ion-exchange column through sodium phosphate injection. The linear range of D-alanine concentration is 1.1 X 10(-6) to 1.1 X 10(-4) mol/l and the detection limit was 4.5 X 10(-7) mol/l (3 sigma). The proposed method has been successfully applied to the determination of D-amino acid in human serum. (C) 2000 Elsevier Science S.A. All rights reserved.