Screen-printed amperometric biosensors for the rapid measurement of L- and D-amino acids

• Published in: Analyst (London) Vol. 124; no. 6; pp. 865 - 870
• Main Authors: SARKAR, P, TOTHILL, I. E, SETFORD, S. J, TURNER, A. P. F
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 1999
• Subjects: Amino Acids - analysis; Animals; Biological and medical sciences; Biomarkers - analysis; Biosensing Techniques; Biosensors; Biotechnology; Cattle; Food Microbiology; Fundamental and applied biological sciences. Psychology; Isomerism; Methods. Procedures. Technologies; Milk - microbiology; TECHNOLOGY; TEKNIKVETENSKAP; Various methods and equipments; Performance evaluation; D stereoisomer; Enzyme; L-Amino-acid oxidase; D-Amino-acid oxidase; Enzyme electrode; Aminoacid; Biosensor; Amperometry; L stereoisomer; Oxidoreductases; Immobilized enzyme; Quantitative analysis
• ISSN: 0003-2654; 1364-5528; 1364-5528
• DOI: 10.1039/a901404g

Screen-printed three-electrode amperometric sensors incorporating L- and/or D-amino acid oxidase for the general purpose measurement of L- or D-amino acids is described. The working electrode incorporates rhodinized carbon, to facilitate hydrogen peroxide oxidation at a decreased operating potential, and immobilized enzyme. The devices responded to all 20 common L-amino acids and all of the D-amino acids examined, the exceptions being L- and D-proline. Linear response profiles were observed for L-leucine, L-glycine and L-phenylalanine with limits of detection of 0.47, 0.15 and 0.20 mM respectively. The devices were reproducible and exhibited stability over a 56 d test period. The biosensor compares favourably with a standard photometric amino acid test and was used to monitor milk ageing effects. The assay is cheap, simple to perform and rapid, requiring only buffer-electrolyte and a small sample volume.