Table 1.

GC-QqQ/MS parameters of the optimized method and retention times of targeted phenolic compounds.

Compounda	Abbreviation	Retention Time (min)	Dwell Time (ms)	Target Ion Transition	Collision Energy (eV)	Reference Ion Transition	Collision Energ (eV)
Trans-cinnamic acid-d7	IS	11.00	25.7	212.0 > 110.2	27.0	110.0 > 82.1	15.0
3-Hydroxybenzoic acid	3-HBA	11.21	26.0	267.0 > 73.2	30.0	267.0 > 193.0	18.0
3-Hydroxyphenylacetic acid	3-HPAA	11.75	26.0	147.0 > 73.1	15.0	296.0 > 73.1	21.0
4-Hydroxybenzoic acid	4-HBA	11.95	25.7	223.0 > 73.1	27.0	193.0 > 73.0	21.0
3-(3-Hydroxyphenyl)propionic acid	3-HPPA	13.08	20.3	192.0 > 177.0	9.0	192.0 > 73.1	21.0
Dihydrocoumaric acid	diHCA	13.44	20.3	179.0 > 73.1	21.0	192.0 > 177.0	12.0
Vanillic acid	VA	13.47	20.0	297.0 > 193.0	30.0	297.0 > 267.0	15.0
Homovanillic acid	HVA	13.54	19.5	209.0 > 73.2	21.0	179.0 > 149.0	27.0
3,4-Dihydroxybenzoic acid	3,4-diHBA	14.05	20.0	193.0 > 137.0	21.0	193.0 > 165.0	15.0
3, 4-Dihydroxyphenylacetic acid	3,4-diHPAA	14.13	31.5	237.0 > 119.0	12.0	237.0 > 209.0	9.0
Hippuric acid	HA	14.33	31.5	206.0 > 73.1	21.0	206.0 > 73.1	21.0
Trans-p-coumaric acid	p-CA	15.34	32.0	219.0 > 73.1	27.0	249.0 > 73.1	30.0
3-(3,4-Dihydroxyphenyl)propionic acid	3,4-diHPPA	15.33	32.0	179.0 > 149.0	30.0	219.2 > 73.2	15.0
Gallic acid	GA	15.45	32.0	281.0 > 179.0	21.0	458.0 > 179.0	42.0
5-(4-Hydroxyphenyl)valeric acid	4-HPVA	15.60	31.5	192.0 > 177.0	15.0	192.0 > 73.2	30.0
Ferulic acid	FA	17.22	98.7	308.0 > 219.0	21.0	338.0 > 249.0	21.0
Caffeic acid	CA	17.90	98.7	219.0 > 191.0	15.0	396.0 > 73.0	27.0
Epicatechin	EC	23.62	73.5	368.0 > 73.2	27.0	179.0 > 149.0	21.0
Catechin	C	23.73	73.5	368.0 > 73.2	30.0	179.0 > 149.0	21.0

^aListed in order of elution. IS, internal standard.