Detection and confirmation of fentanyls in high clay-content soil by electron ionization gas chromatography-mass spectrometry

Detection of illicit drugs in the environment, particularly in soils, often suggests the present or past location of a clandestine production center for these substances. Thus, development of efficient methods for the analysis and detection of these chemicals is of paramount importance in the field of chemical forensics. In this work, a method involving the extraction and retrospective confirmation of fentanyl, acetylfentanyl, thiofentanyl, and acetylthiofentanyl using trichloroethoxycarbonylation chemistry in a high clay-content soil is presented. The soil was spiked separately with each fentanyl at two concentrations (1 and 10 mu g/g) and their extraction accomplished using ethyl acetate and aqueous NH4OH (pH similar to 11.4) with extraction recoveries ranging from not approximate to 56% to 82% for the high-concentration (10 mu g/g) samples while ranging from similar to 68% to 83% for the low-concentration (1 mu g/g) samples. After their extraction, residues containing each fentanyl were reacted with 2,2,2-trichloroethoxycarbonyl chloride (Troc-Cl) to generate two unique and predictable products from each opioid that can be used to retrospectively confirm their presence and identity using EI-GC-MS. The method's limit of detection (MDL/LOD) for Troc-norfentanyl and Troc-noracetylfentanyl were estimated to be 29.4 and 31.8 ng/mL in the organic extracts. In addition, the method's limit of quantitation for Troc-norfentanyl and Troc-noracetylfentanyl were determined to be 88.2 and 95.5 ng/mL, respectively. Collectively, the results presented herein strengthen the use of chloroformate chemistry as an additional chemical tool to confirm the presence of these highly toxic and lethal substances in the environment.

Automated summary

The development of efficient methods for the analysis and detection of illicit drugs in the environment is crucial in the field of chemical forensics. This study presents a method using trichloroethoxycarbonylation chemistry to extract and confirm the presence of fentanyl, acetylfentanyl, thiofentanyl, and acetylthiofentanyl in a high clay-content soil. The results demonstrate the use of chloroformate chemistry as an additional chemical tool to retrospectively confirm the presence of these highly toxic substances.