DUAL ENZYME AMPEROMETRIC BIOSENSOR FOR PUTRESCINE WITH INTERFERENCE SUPPRESSION

A putrescine biosensor has been developed. Putrescine oxidase, peroxid ase, and bovine serum albumin were cross-linked directly on the surfac e of a graphite electrode by glutaraldehyde. The sensor was used to de termine putrescine at 0 mV (vs. Ag/AgCl reference electrode) in a pota ssium phosphate buffer (pH 7.4) solution containing 4 mM dopamine (3-h ydroxytyramine). The response of putrescine was linear up to 600 mu M with a standard deviation of 2.8%. The detection limit was 5 mu M. The response time was around 30 s. The lifetime was-over 30 days when the electrode was used every day. The interferences of cadaverine and spe rmidine could be eliminated by added dopamine which, apparently, inhib its the enzymatic conversion of these substrates more strongly than th at of putrescine.