Analysis of fragmentation pathways of fentanyl derivatives by electrospray ionisation high-resolution mass spectrometry.

Rationale: During the last decade there has been a large increase in the availability of new synthetic opioids on the European drug market. Fentanyl analogues accounted for a significant proportion of these compounds. When there is a rapid introduction of new compounds from a given chemical class onto the market, a computer-assisted library search is not recommended and the spectra have to be interpreted individually.