Frequent Questions

For SW-846 Method 8330B, are the Appendix A drying, sieving, and crushing steps included in the 14 days holding time, or does the 14 days start after the sample is dry?

Method 8330B says that the holding time is the same as semivolatiles, which SW-846 Chapter 4 lists as 14 days from sample collection. Are the 8330B Appendix A drying, sieving, and crushing steps included in the 14 days or does the 14 days start after the sample is dry?

 

If you have to follow the method prescriptively, the drying, crushing, and sieving parts of the sample preparation would need to be completed within 14 days; prior to the extraction phase of the preparation.  When the extraction begins, the 14-day hold time clock stops.  We realize that this presents a problem for 8330B, as the potentially explosive samples must be dried at room temperature.

Reference 17 from 8330B may be useful as it discusses the drying, crushing and sieving parts, and it includes information on a holding time study.  The data in that reference, at least for the compounds chosen, indicates that the 14-day hold time is not an issue.  We advise to seek guidance for your holding time question from your regulator or data user (e.g., DoD). 

Using the performance-based approach and methods innovation rule (MIR), www.epa.gov/hw-sw846/final-rule-methods-innovation-rule-mir, with Method 8330B, if you can demonstrate a longer hold time is supported for your compounds of interest on representative samples for your study, then your regulatory agency may allow a longer period of time to complete sample preparation before extraction.

Other category: Holding Time & Preservation

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