Utility of gas chromatography infrared spectroscopy (GC-IR) for the differentiation of positional isomers of fentanyl related substances

Forensic laboratories routinely use gas chromatography mass spectrometry (GC–MS) in the identification of controlled substances using both retention time and electron impact ionization (EI) spectra. Certain drugs such as positional isomers some fentanyl related (FRS) can produce indistinguishable EI spectra but may be differentiated time. The core structure consists an amide group, a piperidine ring, aniline N-alkyl chain, each providing opportunities for points substitution that create FRS corresponding isomers. For this study, analysis by GC coupled to vapor-phase infrared spectroscopy detector (GC-IR) was used complementary technique GC–MS FRS. result is novel library consisting 212 different reference compounds. A collaboration among three yielded correct identifications twenty blind samples when searched against GC-IR created at Florida International University (FIU). expected limits detection range between 0.10 0.19 mg/mL, depending on sample introduction (injector) method other instrumental parameters. newly its counterpart are shared supplementary materials future researchers practitioners.