A carbon paste electrode modified by entrapped toluidine blue-O for amperometric determination of l-lactate Original Research Article

In this study a new approach to enhance the analytical performance of modified carbon paste electrode with l-LDH (l-lactate dehydrogenase), NAD+ (nicotinamide adenine dinucleotide) and TBO (toluidine blue-O) is described. This approach consists of entrapping the mediator on carbon powder using two properties of the proteins: adsorption on the graphite powder and cross-linking with glutaraldehyde. The immobilisation of TBO in the carbon paste matrix showed that TBO responds rapidly to the variation of NADH concentration in the vicinity of the electrode surface with good repeatability.