Table S2.

MS/MS parameters and LC retention time for target xanthine alkaloids

Compound	Parent ion (m/z)	Fragment ion (m/z)	Collision energy (eV)	MS scan function	Retention time (min)
Xanthine	153	110	17	1	4.67
1-Methylxanthine	167	110	17	2	9.36
3-Methylxanthine	167	124	17	2	8.82
7-Methylxanthine	167	124	17	2	8.23
Theobromine	181	138	17	3	12.09
Theophylline*	181	124, 96	30	3	12.92
Paraxanthine*	181	124, 55	35	3	12.70
Caffeine	195	138	14	4	15.69

^*The most abundant fragment ion is listed first.