Table 1.

Observed MRM transitions and MS settings.

Compounds	MRM transition (m/z)	Retention time (min)	DPa (V)	FPb (V)	CEc (eV)	CXPd (V)
Analytes
ARG	175.2 → 70.0	3.38	40	200	30	15
15N4-ARG	179.2 → 71.1	3.38	40	200	30	15
CIT	176.2 → 70.1	2.82	28	200	30	12
ADMA	203.2 → 46.2	3.84	40	300	40	8
SDMA	203.2 → 172.2	3.66	40	300	20	8
Internal Standards
13C6-ARG	181.2 → 74.2	3.38	40	200	30	15
D4-CIT	180.2 → 74.1	2.81	28	200	40	12
D7-ADMA	210.4 → 77.3	3.82	40	300	40	8

^aDeclustering potential

^bFocusing potential

^cCollision energy

^dCollision cell exit potential.