Analysis of 29 fentanyl analogs and their fragmentation mechanism by liquid chromatography-quadrupole time-of-flight mass spectrometry

Given the wide variety of fentanyl analogs, the test for this entire group tends to be crucial and particularly difficult since all fentanyl-like substances are listed as controlled substances in China. This study meticulously analyzed the fragmentation pathways and mechanisms of 29 fentanyl analogs and summarized the fragmentation pathways and features for the entire group of fentanyl analogs, thus providing a reference for related screening tests. Fentanyl, thiofentanyl, and sufentanil were selected as the representative compounds in this study, and the fragmentation mechanism of their fragment ions was interpreted. The general fragmentation rules for fentanyl analogs were summarized as well. The fragment ions of the three compounds formed by induced cleavage (i) came with high abundance ratios, such as fragment ions of 188, 105, 194, 111, and 238, while the induced cleavage was due to the amide and piperidinyl groups. Moreover, the induction ability of amide group was significantly stronger than that of th