Best Known Method for Clean Fluid Sampling to Get Consistent Measurements During Offline Particle Analysis

A complete chemical quality monitoring program includes data gathered from the time chemicals are received all the way to the point of process. Throughout this monitoring program, the best known method (BKM) which provides optimal data quality and time resolution is continuous in-line monitoring. However, physical and environmental challenges posed by some chemicals and how they are used can make in-line monitoring unfeasible.

An alternative approach is to use grab samples and offline particle contamination monitoring to understand chemical quality. Establishing a well-controlled sampling protocol that does not contaminate the fluid and produce false positives is critical for successful grab sampling.

BKMs to minimize external contamination in the sample are presented here to support data optimization.

It should be expected that samples gathered from different taps will induce some level of tap to tap variability. Samples taken at different locations in the distribution or manufacturing system represent varying quality throughout the system. If assessments regarding chemical quality changes over time are to be made, it is recommended to only compare samples from the same tap and how its data changes over time.

Customers are encouraged to incorporate these concepts in their own process development.

Topics discussed in this paper:

• Recommended methods of ensuring fluid cleanliness
• Source contamination
• Sample collection valves, tubing and variability
• Atmospheric and human contamination