Table 2.

Volatile extract composition of Borago officinalis seeds.

No.	Retention time on DB-WAX (min)	Compounds	RIs		Identification and MS ions (EI)a	Total area (%)	Approximate concentration (μg/mL extract)b
			DB-WAX	HP-1
1	2.64	3-Methyl butanal	925	<700	++++; M+ 86 (16.67), 44	10.8	B
2	3.50	2-Pentanone	987	<700	++++; M+ 86 (20.02), 43	18.0	A
3	5.00	2,3-Pentanedione	1069	<700	+++; M+ 100 (16.32), 43	0.7	C
4	5.41	Hexanal	1086	779	++++; M+ 100 (1.21), 44	10.8	B
5	5.97	3-Pentanol	1110	<700	++++; M+ 88 (0.65),59	0.4	B
6	6.28	2-Pentanol	1124	<700	++++; M+ 88 (1.03), 45	1.2	C
7	6.62	2-Butyl furan	1139	880	+++; M+ 124 (13.46), 81	0.3	C
8	6.85	1-Butanol	1148	<700	++++; M+ 74 (1.86), 56	0.1	D
9	7.81	2-Heptanone	1185	872	++++; M+ 114 (6.60), 43	0.9	C
10	7.90	Heptanal	1188	881	++++; M+ 114 (2.01), 70	1.2	C
11	8.24	Dodecane	1200	1199	++++; M+ 170 (4.12), 57	0.2	D
12	8.71	(E)-2-Hexenal	1219	829	+++; M+ 98 (22.10), 41	0.7	C
13	9.12	2-Pentyl-furan	1236	981	+++; M+ 138 (18.35), 81	1.9	C
14	9.60	1-Pentanol	1254	759	++++; M+ 88 (1.16), 42	1.3	C
15	9.74	Styrene	1259	875	+++; M+ 104 (100.00), 103 (48.72)	0.3	C
16	9.93	Methyl-pyrazine	1267	796	+++; M+ 94 (100.00), 67 (47.31)	0.5	C
17	10.51	2-Octanone	1287	964	+++; M+ 128 (6.18), 43	0.7	C
18	10.63	Octanal	1290	980	++++; M+ 128 (1.20), 43	0.8	C
19	10.87	1-Hydroxy-2-propanone	1299	<700	+++; M+ 74 (11.62), 43	0.3	C
20	10.96	1-Octen-3-one	1302	959	++++; M+ 126 (0.96), 55	0.5	C
21	11.39	2,5-Dimethyl-pyrazine	1320	885	+++; M+ 108 (93.21), 42	0.3	C
22	11.50	(Z)-2-Heptenal	1325	932	+++; M+ 112 (6.85), 41	0.8	C
23	11.57	2,6-Dimethyl-pyrazine	1327	882	++++; M+ 108 (100.00), 42 (90.15)	0.3	C
24	11.67	2-Methyl-3-octanone	1331	1074	+++; M+ 142 (4.55), 43	0.2	D
25	12.32	1-Hexanol	1356	862	++++; M+ 102 (0.58), 56	0.9	C
26	13.07	2-Ethyl-6-methyl-pyrazine	1383	976	+++; M+ 122 (65.87), 121	0.2	D
27	13.25	2-Nonanone	1390	1072	+++; M+ 142 (8.94), 43	0.5	C
28	13.38	Nonanal	1394	1083	++++; M+ 142 (1.01), 57	1.6	C
29	13.70	(E)-3-Octen-2-one	1406	1014	+++; M+ 126 (14.38), 43	0.3	C
30	14.26	(E)-2-Octenal	1430	1034	+++; M+ 126 (3.29), 41	0.8	C
31	14.88	1-Octen-3-ol	1454	981	++++; M+ 128 (0.60), 57	1.6	C
32	14.96	Acetic acid	1457	<700	++++; M+ 60 (76.08), 43	2.7	B
33	15.21	Furfural	1467	802	++++; M+ 96 (100.00), 95 (99.23)	1.8	C
34	15.76	(Z)-6-Nonenal	1488	1007	+++; M+ 140 (0.85), 41	0.2	D
35	15.93	2-Decanone	1494	1173	+++; M+ 156 (5.11), 58	0.4	C
36	16.53	Pyrrole	1518	748	++++; M+ 67 (100.00), 39 (64.74)	0.3	C
37	16.60	Benzaldehyde	1521	929	++++; M+ 106 (96.18), 77	0.8	C
38	16.93	2-Nonenal	1535	1144	+++; M+ 140 (3.96), 43	0.5	C
39	17.33	Linalool	1552	1088	++++; M+ 154 (1.24), 71	0.2	D
40	17.53	1-Octanol	1560	1069	++++; M+ 130 (0.34), 56	0.4	C
41	17.88	5-Methyl-2-furancarboxaldehyde	1574	939	+++; M+ 110 (100.00), 109 (79.03)	0.2	D

EI = electron impact; GC–MS = gas chromatography–mass spectrometry; RI = retention index.

^aThe reliability of the proposed identification has been indicated according to the following: ++++, mass spectrum and retention indices both on polar and nonpolar columns agreed with those of the standards, mass spectral libraries and literature; +++, mass spectrum and retention indices both on polar and nonpolar columns agreed with mass spectral libraries and the literature; ++, mass spectrum and retention index on a polar column agreed with the mass spectral libraries and the literature. MS ions (EI) were given by GC-MS on a DB-WAX column. They consisted of molecular ion M+ (relative abundance) and the base peak ion, or the peak ion with the second-highest relative abundance if the molecular ion was the base peak.

^bA: 500–1000; B: 100–500; C: 10–100; and D: 1–10.