TABLE 3.

GC–MS fragmentation of fentalogs

Compound #	RT (min.)	Base peak (m/z)	Fragmentation (m/z)	EC50 (SEM) nM
18	12.79	293	43, 180, 223, 293	>2000
7	14.41	287	71, 146, 189, 287	390 (96)
5	13.92	285	69, 146, 189, 285	600 (190)
29	12.88	279	57, 180, 223, 279	>1000
15	11.32	277	43, 164, 207, 277	42 (13)
16	11.06	277	43, 164, 207, 277	>500
21	11.82	277	43, 164, 207, 277	60 (15)
17	11.85	273	105, 160, 203, 273	>1000
3	12.84	271	69, 160, 203, 271	>1000
4	13.24	271	55, 146, 189, 271	160 (30)
23	11.57	263	57, 164, 207, 263	15 (4)
24	11.39	263	57, 164, 207, 263	164 (24)
25	11.39	263	57, 164, 207, 263	79 (22)
12	11.72	261	55, 164, 218, 261	14 (1)
13	11.48	261	55, 164, 218, 261	84 (11)
22	12.48	261	45, 105, 158, 261	>500
14	11.49	259	43, 146, 189, 259	137(13)
20	11.83	259	105, 146, 189, 259	80 (22)
26	12.08	259	91, 160, 203, 259	58 (10)
27	11.84	259	91, 160, 203, 259	450 (75)
28	12.29	259	105, 160, 203, 259	>1000
30	11.78	259	105, 160, 203, 259	4.2 (0.6)
31	11.66	259	91, 105, 160, 259	25(6)
2	12.44	257	69, 146, 189, 257	55 (10)
Fentanyl (1)	11.80	245	91, 146, 189, 245	32 (8)
9	11.67	245	91, 160, 202, 245	>1000
10	11.57	245	56, 91, 110, 245	>500
32	10.85	245	57, 146, 189, 245	350 (7)
33	13.21	245	93, 146, 189, 245	138(21)
34	11.53	245	91, 146, 189, 245	>500
11	11.73	243	55, 146, 200, 243	68 (16)
8	10.72	231	91, 146, 188, 231	>2000
6	14.24	95	95, 187, 240, 283	9.3 (1.9)
19	11.87	57	57, 105, 146, 273	531 (136)

Note. Parent compounds and their fragments are organized in order of descending base peak number. Red highlights the fluorinated analogs with the m/z 164 fragment.

Abbreviations: GC-MS, gas chromatography-mass spectrometry; RT, retention time.