
Initial QC:
- Recommended for Routine Changes
- Verify reagent acceptability
- Recommended for Occasional Changes and Required for Substantive Changes:
- Initial Precision and Recovery - 4 reagent water spikes
- Method Blank - 1 reagent water unspiked
- Strongly Recommended for Substantive Changes:
- Matrix Spike/Matrix Spike Duplicate/Unspiked Field Sample
On-going QC:
- Process all Matrix Spike samples with the same modifications as the associated field sample
- Process On-going Precision and Recovery samples with the substantive modification on the same percentage of samples as the modification is used on field samples, i.e., if 25% of field samples are processed with an additional wash, 25% of OPRs and MBs should be processed with the additional wash.