Table 2.

Identified chemical components of Yarrow (Achillea millefolium L.) essential oil.

No	Retention Time (min)	KI a	KI b	Identified Compounds	Area c (%)
1	9.425	957	952	α-Pinene	1.49
2	9.746	963	953	Camphene	2.97
3	10.145	985	976	Sabinene	0.53
4	10.294	991	980	β-Pinene	0.97
5	11.117	1028	1026	p-Cymene	0.89
6	11.225	1033	1031	β-Ocimene	1.75
7	11.413	1042	1039	Eucalyptol	17.07
8	12.762	1102	1098	Linalool	3.57
9	12.904	1109	1110	α-Thujone	12.10
10	13.005	1114	1115	Cyclooctanone	1.60
11	13.078	1117	1115	β-Thujone	3.81
12	13.250	1126	1138	cis-Limonene oxide	1.44
13	13.779	1151	1143	Camphor	18.55
14	13.975	1160	1162	Pinocarvone	1.63
15	14.062	1164	1169	Lavandulol	1.14
16	14.249	1173	1165	Borneol	3.78
17	14.647	1192	1189	α-Terpineol	7.23
18	14.772	1198	1202	Myrtenol	0.51
19	15.471	1231	1242	Carvone	0.64
20	16.199	1269	1256	Neral (β-citral)	1.95
21	16.496	1284	1274	Geranial (α-citral)	2.51
22	16.755	1297	1294	Limonene dioxide	2.40
23	20.390	1493	1383	Geranyl acetate	1.65
24	22.069	1601	1583	Caryophyllene oxide	0.51
25	22.206	1609	1575	Spathulenol	0.79
26	22.814	1684	1525	1-Naphthalenol	1.23
27	23.181	1734	1652	α-Eudesmol	0.82
				Total identified compounds (%)	94.65

A DB-5 column (polydimethylsiloxane, dimensions: 60 m × 0.25 mm), a flame-ionized detector operating at electron ionization mode at 70 eV, and carrier gas of helium at a flow rate of 1.2 mL/min were used for the characterization of GC-MS components. The compounds are listed in order of their retention time on the DB-5 column. KI ^a: Experimental Kovats indices calculated from the GC-MS chromatogram. KI ^b: Kovats indices matching with those of published literature (NIST, Wiley). ^c Relative percentages of constituents using peak area normalization. (i.e., the peak areas for solvent compounds appeared earlier than the lowest number of n-alkanes (e.g., RT of 9.425 in this study) were discarded and the area of individual peaks was normalized).