The Chromatography Forum

of Delaware Valley

Unlike other matrices, forensic biological samples are highly variable, degraded, and unpredictable, making them among the most analytically challenging specimens. Postmortem blood, decomposed tissues, vitreous humor, and alternative matrices can produce unexpected chromatographic behavior that compromises identification and quantitation. This presentation reviews anomalies encountered in LC-MS/MS, and GC-MS casework, including retention time shifts, peak distortion, ion suppression or enhancement, isobaric interferences from decomposition products, in-source conversion of labile analytes, and internal standard variability. Many anomalies are sample-specific and would have passed standard acceptance criteria, risking false positives, false negatives, or biased results. Mitigation strategies included improved sample preparation, chromatographic optimization, and critical review of raw data. Because no validation can fully capture matrix variability, laboratories should evaluate real-case matrices and continuously monitor chromatographic performance to ensure defensible toxicological findings.