Table 1.

Analyte-specific relative retention times and tandem mass spectrometer working parameters for IS, TH and TAM

No.	Analyte	IS reference	Relative RT ± SD	PI (m/z)	Pro 1 (m/z)	Pro 2 (m/z)	DP, eV	CE, eV	CXP, eV
	13C6-3,5,3′,5′-T4	13C6-T4	1	783.6	738.0	611.0	106	33	20
	13C6-3,5,3′-T3	13C6-T4	0.930 ±0.001	657.7	611.8	203.1	80	30	20
	13C6-3,3′,5′-rT3	13C6-T4	1.063 ±0.003	657.7	611.6	514.0	166	33	22
	13C6-3,3′-T2	13C6-T4	0.967 ±0.002	531.8	485.7	359.0	116	29	18
	2H4-3-T1AM	2h4-t1am	1	359.9	342.8	216.1	81	17	12
1	T0		0.757 ±0.001	274.0	215.1	118.1	51	25	6
2	3-T1		0.840 ±0.002	399.9	353.9	341.0	96	23	14
3	3′-T1		0.895 ±0.001	399.9	341.0	353.9	131	29	14
4	3,5-T2		0.846 ±0.003	525.8	479.8	353.0	91	27	18
5	3,3′-T2	13C6-T4	0.967 ±0.002	525.8	479.9	381.9	116	27	18
6	3′,5′-T2		1.007 ±0.002	525.8	508.8	466.8	146	23	18
7	3,5,3′-T3		0.929 ±0.001	651.7	605.6	478.9	131	33	24
8	3,3′,5′-rT3		1.062 ±0.003	651.7	605.8	478.9	130	47	9
9	3,5,3′,5′-T4		0.999 ±0.001	777.6	731.6	604.7	121	37	28
10	3,5,3′,5′-T4AM		1.248 ±0.002	733.6	716.5	335.8	156	29	28
11	3,5,3′-T3AM		1.130 ±0.002	607.7	590.7	209.9	141	25	24
12	3,3′,5′-rT3AM	2h4-t1am	1.354 ±0.004	607.7	590.7	209.9	136	23	22
13	3,5-T2AM		1.000 ±0.002	481.8	464.9	337.8	121	21	18
14	3-T1AM		1.000 ±0.000	355.8	338.9	212.1	91	15	10
15	T0AM		0.865 ±0.001	230.0	213.0	108.8	11	15	12

The circled iodine atoms can be replaced by hydrogen, giving rise to the various thyronines (upper figure) or TAM (lower figure) metabolites. m/z = Mass-to-charge ratio; PI = precursor ion; Pro = product ion; DP = declustering potential; CE = collision energy; CXP = collision cell exit potential.