Changes in the Chemical Components of Processed Rehmanniae Radix Distillate during Different Steaming Times

Table 2

Volatile constituents and content in Dis1–Dis9 by GC-MS.

No	tR	Compounds	MW	Molecular formula	RI (measured values/theoretical value)	Different steaming times (contents)
1	5.51	Propanoic acid	118	C5H10O3	810/815	1 (5.57%), 4 (0.45%), 5 (1.51%), 6 (1.35%), 7 (2.1%), 8 (0.86%), 9 (2.26%)
2	6.65	Furfural	96	C5H4O2	832/833	1 (0.08%), 2 (0.29%), 3 (0.54%), 4 (0.22%), 5 (0.28%), 6 (0.01%), 7 (0.01%), 8 (0.01%), 9 (—)
3	7.76	2-Furanmethanol	98	C5H6O2	853/859	1 (0.01%), 2 (0.01%), 3 (0.28%), 4 (0.41%), 5 (0.12%), 6 (0.08%), 7 (0.02%), 8 (0.01%), 9 (—)
4	30.69	2-Acetylpyrrole	109	C6H7NO	1086/1064	1 (0.02%),
5	32.78	Phenylethyl alcohol	122	C8H10O	1086/1116	1 (0.44%)
6	37.49	2(3H)-Furanone	102	C4H6O3	1167/1169	1 (0.26%), 2 (0.22%), 3 (0.41%), 4 (0.31%), 5 (0.28%), 6 (0.25%), 7 (0.25%), 8 (0.21%), 9 (0.2%)
7	38.42	4H-Pyran-4-one	142	C6H6O4	1186/1196	1 (0.23%)
8	41.30	5-Hydroxymethylfurfural	126	C6H6O3	1228/1233	1 (3.02%), 2 (24.58%), 3 (62.04%), 4 (57.13%), 5 (74.11%), 6 (69.26%), 7 (66.7%), 8 (64.9%). 9 (56.35%)
9	45.08	Acetic acid	166	C9H10O3	1296/	1 (0.88%), 2 (0.57%), 3 (0.55%), 4 (0.86%), 5 (0.26%), 6 (0.17%), 7 (0.01%), 8 (—), 9 (0.04%)
10	50.99	2-(4-Hydroxyphenyl)ethanol	138	C8H10O2	1426/1434	1 (2.21%), 2 (0.64%), 3 (0.86%), 4 (1.05%), 5 (0.2%), 6 (0.01%), 7 (0.43%), 8 (0.4%), 9 (0.59%)
11	56.74	3-Hydroxy-4-methoxybenzoic acid	168	C8H8O4	1560/	1 (0.54%), 3 (0.2%), 4 (0.16%), 5 (0.14%), 6 (0.08%), 7 (0.03%), 8 (0.01%), 9 (—)
12	70.76	Dibutyl phthalate	278	C16H22O4	1959/1965	1 (13.35%), 2 (13.28%), 3 (5.56%), 4 (13.01%), 5 (5.43%), 6 (10.62%), 7 (10.35%), 8 (11.7%), 9 (12.29%)
13	26.49	L-Lactic acid	90	C3H6O3	840/838	1 (50.09%), 2 (1.09%), 3 (0.17%), 4 (0.12%), 5 (0.05%), 6 (0.06%), 7 (—), 8 (—), 9 (—)