Table 1.

Single reaction monitoring (SRM) transitions

Analyte	RTa (min)	SRM transitions (m/z)	CE (eV)
Glycine	1.4	76 → 30	11
Glycine-d2	1.4	78 → 32	7
Serine	1.15	106 → 60	10
Serine-d3	1.15	109 → 63	11
Cysteine	1.4	122 → 59	20
Cysteine-d2	1.4	124 → 61	23
Taurine	0.6	126 → 108	11
Taurine-13C2	0.6	128 → 110	11
Homocysteine	2.85	136 → 90	10
Homocysteine-d4	2.85	140 → 94	10
Methionine	4.3	150 → 104	10
Methionine-d3	4.3	153 → 107	9
Pyridoxine	4.5	170 → 134	18
Pyridoxine-d2	4.5	172 → 136	19
Pyridoxamine	5.75	169 → 152	11
Pyridoxamine-d3	5.75	172 → 155	12
Homocysteic acid	0.6	184 → 138	10
Homocysteic acid-d4	0.6	188 → 142	9
Cystathionine	5.2	223 → 134	13
Cystathionine-d4	5.2	227 → 138	13
Riboflavin	3.4	377 → 243	15
Riboflavin-13C4 15N2	3.4	383 → 249	13
SAH	5.6	385 → 134	21
SAH-d4	5.6	389 → 136	18
SAM	5.9	399 → 250	14
SAM-d3	5.9	402 → 250	13
DMG	1.25	104 → 58	12
DMG-d6	1.25	110 → 64	15
Betaine	1.4	118 → 58	25
Betaine-d11	1.4	129 → 66	31
Choline	4.35	104 → 60	17
Choline-d9	4.35	113 → 69	19
5-MTHF	4.9	460 → 313	15
5-MTHF-13C5	4.9	465 → 313	26

^aRT retention time given as information only