SIMULTANEOUS DETERMINATION OF LACTOSE AND GLUCOSE IN MILK USING 2 WORKING ENZYME ELECTRODES

Lactose and glucose concentrations were determined simultaneously by u sing a measuring-cell containing lactose and glucose electrodes made b y mixing beta-galactosidase/glucose oxidase and glucose oxidase, respe ctively, with carbon paste. The glucose electrode responds to glucose alone, while the lactose electrode measures the sum of glucose and lac tose. Lactose concentration was calculated by subtracting the glucose concentration from the reading of the lactose electrode. The present d ual-working electrode system permitted the determination of lactose an d glucose concentrations simultaneously from a single measurement over a linear range of 0.1-2.5 mM. Furthermore, it enabled the determinati on of lactose concentration in milk in the presence of glucose to be c arried out more precisely and with a higher degree of sensitivity than the conventional colorimetric method.