3-Methylfentanyl (3-MF) has reappeared in the United States illicit drug market for the first documented time since 1988. In a paper authored by Melissa F. Fogarty et al., published in Drug Testing and Analysis (doi: 10.1002/dta.2414) an analytical method was developed and validated using UCT’s flagship sorbent Clean Screen® DAU (130 mg/ 3 mL). Liquid chromatography time-of-flight mass spectrometry was the instrument of choice for the analysis of (±)- cis-3-MF and (±)-trans-3-MF in blood specimens. The linear dynamic range of this method was 0.1-10 ng/mL.

3-MF presents an analytical challenge, due to presence of cis and trans stereoisomers, each with different potencies, and ultimately very low concentrations in the blood after use. As the estimated dose of this compound is approximately 0.1-0.5 mg with the resulting concentrations in the sub-nanogram range, it is necessary for forensic toxicology laboratories to obtain instruments sensitive enough to detect these substances in driving under the influence of drugs and postmortem cases. Quantitation of 3-MF with separation of (±)-cis and (±)-trans-3-MF provides additional detail for more specific toxicological interpretation.

 Whole blood samples from 25 postmortem cases and 2 human performance case involving 3-MF were submitted for quantitative analysis. The mean and median concentration for the (±)-cis-3-MF were 0.84 ng per mL (±0.81) and 0.66 ng per mL, respectively, range 0.14-3.43 ng per mL. The resulting (±)-trans-3-MF mean concentration was 0.46 ng per mL (±0.38) and the median concentration was 0.37 ng per mL with a range of 0.11-1.90 ng per mL. The resulting (±)-cis-3-MF and (±)-trans-3-MF concentrations were summed to give the total amount of 3-MF present in the case with the resulting average concentration at 1.28 ng per mL (±1.16), median at 1 ng/mL and range 0.18- 5.18 ng per mL.

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