LACTATE SOLID-STATE BIOSENSOR WITH MULTILAYER OF ELECTRODEPOSITED POLYMERS FOR FLOW-INJECTION CLINICAL ANALYSIS

In the lactate biosensor, electrodeposited poly(o-phenylenediamine) se rves as a convenient matrix for the immobilization of lactate oxidase, but does not provide sufficient discrimination from several interferi ng species present in physiological fluids. Their effect, however, can be eliminated by additional modification of the working Pt electrode with a bilayer of electrodeposited polypyrrole/polyphenol. Despite con tinued decrease in biosensor sensitivity, the newly developed three-la yer solid-state biosensor was successfully applied in flow-injection d etermination of lactate in both undiluted and diluted human blood seru m samples over a 10 day period. For the lactate concentration range 0. 2-5.0 mM in several series of measurements the correlation coefficient values for comparison with photometric determination using a DuPont d imension clinical analyzer were between 0.96 and 0.99. The reproducibi lity measured for 1:10 diluted serum was 0.6%. The detection limit was estimated as 2 mu M. (C) 1996 Elsevier Science Limited