Table 2.

Mass spectrometric and MS/MS fragmentation patterns of caffeine, theophylline and theobromine [110].

Methylxanthine	[M + H]+	MS Data (MS/MS Fragmentation Pattern)
Caffeine	195.2	181.2, 151.2, 138.0
Theophylline	181.2	167.2, 153.2, 123.5
Theobromine	181.2	167.2, 153.2, 107.5