US EPA Method 533 QC Failure Diagnostic & Advisor Wizard
Level 2 Warning: Soil Matrix Effect
Soil
Core Co-extractive Matrix Induced RT Delay
EPA 533 § 9.4.2
Complex soil humic/fulvic acid co-extractives slightly retard the C18 partition equilibrium of the
perfluorooctyl hydrophobic tail, causing a reproducible retention shift from 5.988 min to 6.095 min.
Root Cause Probability:
Soil Humic Co-extractives: 72%
Guard Column Phase Saturation: 18%
Mobile Phase Buffer Gradient Drift: 10%
Recommended Official Action: Apply manual integration override with EPA 533 compliant
retention time window shift (+0.107 min) documented in 21 CFR Part 11 audit log.