Description:
<jats:title>Abstract</jats:title><jats:p>A specific continuous‐flow analytical system for determination of lactose concentration in a liquid mixture of constituent sugars was developed and tested based on a series of enzymatic reactions. Lactose and glucose oxidase immobilized on a phenol–formaldehyde resin were employed. More detailed study was carried out based on a reaction by‐product quantitatively detected by an available iodide electrode. A multichannel proportioning pump fed two independently operated analytical streams eliminating thus the background glucose interference. With a goal of lactose concentration control in a fermentation process, the system response time delay was shortened to approximately 15 min. Apart from optimization of the analytical system operating parameters, the study indicates also the major application problem areas: lactase inhibition by galactose, galactose oxidation by glucose oxidase, and a partial loss of glucose oxidase activity in a prolonged continuous‐flow operation. A manual Colorimetric Procedure was employed to verify the results of the potentiometric method.</jats:p>