Table 1:

Methylated metabolites and their SRM transitions

Class	Metabolite	Precursor ion (m/z)	SRM (m/z)	Polarity	RT (min)
Methylated acids	Methyl chloroformate	95	58	Positive	5.4
	Methyl phosphonic acid	97	79		6
	Methyl-4-amino benzoate	152	120/93		3.7
	Methyl-4-hydroxy benzoate	153	121/59		5.4
	Methyl malonic acid	117	73/55	Negative	3.1
	Methyl succinic acid	131	87/113		6
Methylated amino acids	N-methyl-L-alanine	104	58	Positive	6.3
	1-methy-L-histidine	170	124/83		6.8
	1-methyl-D-tryptophan	219	173/160		6.6
	S-(5'-adenosyl)-L-methionine	399	136/250		7
	2-methyl glutaric acid	145	101	Negative	6
	3-hydroxy-3-methyl glutaric acid	161	57/99		6
	5-methoxy-3-indole acetic acid	204	160/145		5.3
Methylated nucleotides	5-methylcytosine	126	109	Positive	5.4
	1-methylnicotinamide	138	79/93		6.3
	6-O-methyl gauanine	166	149/134		5.3
	2-amino-6-methyl mercaptopurine	182	134/107		5.1
	5-methyl cytidine	258	126/109		6.4
	7-methyl guanosine	299	167		5.4
	6-methyl -2-thiouracil	141	58	Negative	5.4
	5-deoxy-5-methyl thio adenosine	296	134		5.3