The article contains information on the properties of fentanyl derivatives and a method for their simple orientation identification. Thin-layer chromatography (TLC) was deliberately chosen to perform the experiment because it is the most suitable method for rapid analysis of the collected sample under the conditions of the field chemical laboratory operated by the Army of the Czech Republic. On the basis of the experimental work performed, it was found that the most suitable system for the identification of the fentanyl derivatives of interest by TLC is a system where the stationary phase consists of "alumina 60 F254 neutral" and the mobile phase is comprised of ethyl acetate and hexane in a ratio of 7:3. The findings are fully usable in practice and will be included in the standard operating procedures for the determination of these types of substances in the Field Transport Chemical Laboratory PPCHL-AL2/ch, most likely in the form of a certified methodology.