Screen-printed amperometric biosensors for the rapid measurement of L- and D-amino acids.
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.
Sarkar
P
P
Cranfield Biotechnology Centre, Cranfield University, Bedfordshire, UK.
Tothill
I E
IE
Setford
S J
SJ
Turner
A P
AP
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*
D000596:Amino Acids; D015415:Biomarkers