Characterization of Critical Factors Affecting the Stabilization Time of Particle Measurements in Ultra-Pure Water Systems
Particle measurements in ultra-pure water (UPW) systems can take a considerable time to return to a stable baseline after an event interrupt normal operation (such as maintenance shutdowns). A characterization study was performed to evaluate the contribution of critical factors to the stabilization time of measurements in UPW for particles 20 nm and above. It was found that invasive actions, such as installing new sample tubing and components, had the most significant impact on the stabilization time. In contrast, non-invasive actions, such as PTFE and PFA valve actuation and the typical warm-up period of the particle counter, had much less influence. It was also shown that specific measures, such as adequate flushing of new tubing and components and minimizing sample tubing lengths, can effectively reduce the particle clean-up time.
In this paper, an Ultra-DI 20 Liquid Particle Counter instrument is used to characterize the clean-up time after various actions.