Device for electrochemically determining the partial pressure of oxygen in a liquid and method for operating the device

摘要

A device for electrochemically determining the partial pressure of oxygen in a liquid (6) contains a measuring sensor (3) having a working electrode W and a counterelectrode C. The thin-film electrodes (30, 32) are located on a substrate (36) in a measuring channel (16) to which the test medium (6) and a rinsing medium (8) can be alternately fed and which connects a device (18) for controlling the flow velocity of the test medium (6) to a lumen (11) of a double-lumen catheter (10). The second lumen (12) can be fed with the rinsing medium (8) with a reversible flow direction. Both lumens (11, 12) have a common mouth (14) which can be introduced into the test medium (6). In this device, poisoning of the electrodes (30, 32) is prevented because they each alternately have, in a test phase M, test medium (6) and, in a regenerating phase R, rinsing medium (8) flowing around them. ……