Disposable amperometric biosensor for the determination of tyramine using plasma amino oxidase

We have developed screen–printed carbon electrodes for the determination of tyramine (Tyr) via plasma amine oxidase. The enzyme was immobilized on the carbon working electrode by cross–linking it with bovine serum albumin using glutaraldehyde. The employment of the mediator hydroxymethylferrocene lowers the working potential to +260 mV (vs. a screen–printed Ag/AgCl reference electrode). The effects of pH, potential and mediator concentration were optimized and resulted in reproducibility and repeatability values of 8.6 % and 8.7 %, respectively. Response is linear in the range from 2 to 164 μM, and the limit of detection is 2.0 ± 0.18 μM. The effects of potentially interfering biogenic amines such as putrescine, cadaverine, histamine, spermine, spermidine and tryptamine were also evaluated. The biosensor was successfully applied to the determination of Tyr in cheese.