On-line amperometric analysis system and method incorporating automatic flow compensation

摘要

An amperometric analysis system and method includes a flow tube constituting the amperometric cell in which magnetic flow metering electrodes function also as the counter and test electrodes for amperometric measurement. By combining the magnetic flow measurement with the amperometric measurement, additional electrodes are not needed to obtain the flow signal for compensating the amperometric measurement. Ultrasonic drivers are mounted on the end of the shank of the counter and test electrodes and driven by an ultrasonic oscillator to activate the electrodes to keep them clean. Complementary cleaning can be obtained through the simultaneous application of an electrochemical anodic pulse. The system includes a three-electrode circuit potentiostat in which the potential of the test electrode is fixed versus a reference electrode and the current flows between the test electrode and the counter electrode. An isolated current source allows the magnetic flow metering electrodes to serve simultaneously as test and counter electrodes in the amperometric circuit. The flow tube also includes a thermistor temperature compensator. Reliable direct amperometric analysis of a flowing stream is made possible by the invention.