Table 1 Analysis of monomeric catechins and oligomeric proanthocyanidins in leaf, stem and root of tea plant

Peak/no.	t_R (min)	[M – H]⁺/[M - H]⁻ (m/z)	MS/MS (m/z)	UV λmax (nm)	identification	Leaf	Stem	Root
1	11.060	−/609.11332	−/125,305,423	272	GC-GC	+	+	—
2	14.166	−/305.06385	−/125, 165,179,219	275	gallocatechin^a	+	+	—
3	16.292	−/593.15606	−/289,305, 407,423	270	C-GC	+	+	—
4	16.765	−/425.03299	−/169,273	274	epiafzelechin gallate	+	+	—
5	18.587	−/305.06517	−/125,137,179, 219	275	epigallocatechin^a	+	+	—
6	20.343	−/761.12183	−/125,305,423,591	275	EGC-EGCG	+	+	—
7	20.630	−/289.06836	−/109,125,203,245	278	catechin^a	+	+	—
8	23.668	−/577.12389	−/125,289,407,425,451	273	EC-EC dimer	+	+	—
9	25.018	−/577.12284	−/125,289,407,425,451	273	Procyanidin B2^a	+	+	++
10	26.621	−/745.12819	−/169,407,423,593	278	ECG-EGC	+	+	—
11	27.330	−/289.07148	−/109,125,203,245	278	epicatechin^a	+	+	+
12	30.993	−/457.09664	−/125,169,305	278	epigallocatechin gallate^a	+	+	—
13	34.908	−/865.18022	−/125,407	278	EC-EC-EC PAs trimer	+	+	++
14	35.280	−/729.13377	−/125,245,407,577	278	EC-ECG	+	+	—
15	35.823	−/897.15219	−/−	278	ECG-EGCG or EGC-EGC-EC	+	+	—
16	36.596	−/273.07432	−/97,229	275	epiafzelechin	+	+	—
17	38.132	−/729.17308	−/289,407, 441,559	278	EC-ECG	+	+	—
18	50.200	−/441.10108	−/125,169, 271,289	278	epicatechin gallate^a	+	+	—
19	52.896	−/1153	−/−	278	tetrameric procyanidin	—	—	+
20	57.201	−/1441	−/−	278	pentameric procyanidin	—	—	+

Notes: ^aCompounds positively identified by direct comparison with the standard; other compounds were approximately identified qualitatively by comparing the wavelengths of maximum absorbance, protonated and deprotonated molecules ([M - H]⁺/[M - H]^-) and fragment ions (PI/NI) from the published literature; t_R (min) was the retention time in Figure 2. [M - H]⁺/[M - H]^- (m/z) of compounds were detected by LC-TOF-MS; MS/MS (m/z) of compounds were detected by UPLC-TOF-MS/MS. —, not detected; +, detected; ++, signal was stronger.

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