Table 2.

Optimized LC-MS/MS parameters

	Retention time (min)	Precursor ion (m/z)	Product ion (m/z)	Q1 pre bias (V)	Collision energy (eV)	Q3 pre bias (V)
GLYP	2.05	254	102	18	17	20
GLUF	1.73	252	210	10	14	15
AMPA	1.46	182	111	22	18	22
MPPA	1.91	181	149	13	16	28
GLYP13C215N	2.04	257	105	18	17	21
AP-4	2.09	268	166	20	19	11
AP-5	2.59	282	180	11	21	12