Pulsing Technique for Improved Performance of Oxygen Sensors

The results of tests on a new method for improving the performance of membrane covered polargraphic oxygen sensors will be presented. The technique known as chronoamperometry or, more commonly, "pulsed", can be applied to the usage of polargraphic oxygen sensors. The technique offers the advantage of greatly reducing the amount of oxygen consumed from the sample during the process of making a measurement. This is turn greatly reduced the sensor\´s sensitivity to fouling and variations in sample flow rate. Secondary benefits Include long-term stability and extended service because of the very short duty cycle. The effect of fouling was simulated by doubling the membrane thickness; the steady state current was halved, but the current measured at 1. second was unaffected. The effect of a transition from high flow rate to no flow produced a 28-43% decrease in steady current, depending upon whether membrane thickness was 1.0 or 0.5 mil respectively, but the current measured a 1. second declined by only .3-1.2%. The significance of these Improvements to the use of dissolved oxygen sensors for monitoring dissolved oxygen in the ocean will be discussed.