Milk lactate determination with a rotating bioreactor based on an electron transfer mediated by osmium complexes incorporating a continuous-flow/stopped-flow system

摘要

The high sensitivity that can be attained using a bienzymatic system and mediated by the redox polymer[Os(bpy)_2ClPyCH_2NHpoly(allylamine)](Os-PAA),has been verified by on-line interfacing of a rotating bioreactor and continuous-flow/stoppedflow/continuous-flow processing.When the hydrogen peroxide formed by LO_x layer reaches the inner layer,the electronic flow between the immobilized peroxidas and the electrode surface produces a current,proportional to lactate concentration.The determination of lactate was possible with a limit of detection of 5 nmoll~-1 in the processing of as many as 30 samples per hour.This arrangement allows working in undiluted milk samples with a good stability and reproducibility.Horseradish peroxidase[EC1.11.1.7]and Os-PAA were covalently immobilized on the glassy carbon electrode surface(upper cell body),lactate oxidase[EC 1.1.3,x]was immobilized on a disk that can be rotated.