EPA Method 1664A requires the PAR concentration as follows: “The weight must be 40 ± 1 mg” (Section 7.10.3 NOTE) and at least this amount are required for the QCS, OPR, MS, MSD, and IPR samples. (Sections 9.8, 9.7, 9.6.1, 9.3.1, 9.2.2, 7.11 and 7.10) Although certain method modifications are allowed, a change in the PAR concentration is not expressly permitted and “shall be considered a major modification subject to application and approval of alternate test procedures under CFR 136.4 and 136.5.” (Sections 1.7 and 1.8) Why expose the defensibility of your data to unnecessary legal risk? Use 40 mg/L QC samples and achieve higher quality results with Xenomax SPE Filters. Request your free samples here
PAR (Precision and Recovery); QCS (Quality Control Sample); OPR (Ongoing Precision and Recovery); IPR (Initial Precision and Recovery); MS (Matrix Spike); MSD (Matrix Spike Duplicate)
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