title: Screen-printed amperometric biosensors for the rapid measurement of L- and D-amino acids.
abstract: 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.
authors.affiliation: Cranfield Biotechnology Centre, Cranfield University, Bedfordshire, UK.
authors.forename: P
authors.initials: P
authors.lastname: Sarkar
authors.forename: I E
authors.initials: IE
authors.lastname: Tothill
authors.forename: S J
authors.initials: SJ
authors.lastname: Setford
authors.forename: A P
authors.initials: AP
authors.lastname: Turner
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015374:Biosensing Techniques; D002417:Cattle; D005516:Food Microbiology; D007536:Isomerism; D008892:Milk / Q000382:microbiology*
chemical_list: D000596:Amino Acids; D015415:Biomarkers