Table 1.

The target compounds, deprotonated precursors and fragment ions. The common fragments for the parent compound and its derivatives are in bold.

Compound	R.T. (min)	Formula	Exact Mass	Error (ppm)	Adduct Ion (m/z)	MS2 Fragments (m/z)
INH	4.25	C6H7N3O	137.0589	1.47	138.0667	122.0712; 120.0556; 108.04429; 106.0287; 96.0443; 59.0239
INH-a	11.17	C13H11N3O	225.0902	1.25	226.0980	208.08692; 148.0505; 147.05527; 106.0287; 96.0443
INH-b	11.27	C13H10N4O3	270.0753	0.86	271.0831	255.0876; 253.0720; 224.0818; 192.0430; 148.0505; 136.0393; 106.0287; 96.0443
INH-c	13.40	C13H10N3OBr	303.0007	0.5	304.0085	288.0130; 285.9974;224.9658; 224.0818; 168.9647; 148.0505; 106.0287; 96.0443