Gender Discrimination of Flower Buds of Mature Populus tomentosa by HPLC Fingerprint Combined with Chemometrics

Table 2

Four screen compounds identified by UPLC-Q-TOF/MS.

Peak	Rt (min)	Assignment	Formula	ESI (+)		ESI (−)		Reference
				MS^1 (ppm)	MS^2	MS^1 (ppm)	MS^2
4	8.91	Siebolside B^a	C20H22O9	429.1171 [M + Na]^+ (2.1); 407.1346 [M + H]^+ (1.0)	245.0844; 123.0473	405.1192 [M − H]^− (1.5)	243.0616; 121.0288	Standard
9	13.76	Tremulacin^b	C27H28O11	551.1535 [M + Na]^+ (1.1); 567.1257 [M + K]^+ (−2.1); 529.1698 1697 [M + H]^+ (−2.5)	289.0713; 160.9955; 179.0350	527.1561 [M − H]^− (1.5)	405.1185; 155.0341; 137.0236; 121.0288	[34]
14	17.37	NI	C31H23NO3	496.1318 [M + K]^+ (0.6)	301.0737; 213.0983; 147.0482	—	—	—
15	18.14	NI	C18H40NO3	318.3023 [M + H]^+ (2.5)	256.2657; 186.2247	—	—	—

a: identified by reference standard. b: identified by literature. NI: not identified.