Vitreous Humor as an Alternative Matrix for Comprehensive Drug Screening in Postmortem Toxicology by Liquid Chromatography-Time-of-Flight Mass Spectrometry

Liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS) is an emerging technique in toxicological drug screening. The applicability of vitreous humor as an alternative matrix for drug screening by LC-TOFMS in postmortem investigations was studied by comparison of findings in urine and vitreous humor in 50 autopsy cases. In addition, a cutoff value was determined for 70 drugs of toxicological relevance. The comparison study showed that vitreous humor is well-suited for qualitative screening analysis, although representativeness was not as good as urine because of less frequent metabolite detection. A total of 45 parent compounds and 24 metabolites were identified in vitreous samples; for urine, the figures were 55 and 39, respectively. The mean and median cutoff values were 0.072 and 0.023 mg/L, respectively, which are sufficient for routine casework according to the quantitative data available in the literature.