Changes in the Composition of Aromatherapeutic Citrus Oils during Evaporation

Table 1

Percentage composition of Citrus oils as determined by GC-MS. Numbers in parenthesis after chemical names refer to peak numbers on chromatograms. Oils are identified as lemon, tangerine, and sweet orange. Column heads show percentage of oil remaining at analysis point. GC was carried out under the following conditions: VF-1MS column of 25 meters × 200 m (i.d.), film thickness 0.33 m, at helium pressure 81.8 kPa, and rate 0.7 mL/min, with a split/splitless injector. Samples for GC-MS were analysed after dilution 1 : 10 (v : v) and an aliquot (0.2 L) was injected with a 1 : 50 split. Temperature program: initial temperature 50°C, with immediate heating rate of 30°C/min from 50 to 150°C, 8°C/min from 150 to 300°C, and finally 5 min isothermal at 300°C.

Compound (peak numbers)	Essential oils
	Lemon			Tangerine			Sweet orange
	100%	50%	10%	100%	50%	10%	100%	50%	10%
2-Thujene (1)	0.5	0.1
α-Pinene (2)	2.7	0.7		3.2	0.1		1.1	0.2
Camphene (3)	0.1
β-Phellandrene (4)	2.4	1.3		1.2	0.1		0.5	0.1
β-Pinene (5)	17.5	9.8	2.9	8.5	2.4	0.2	3.0	2.8	1.1
α-Phellandrene (6)							0.1
3-Carene (7)							0.1
o-Cymene (8)	1.9	1.5	1.8	0.5	0.1
Limonene (9)	58.6	61.7	61.0	84.3	95.0	96.9	94.6	96.1	97.8
-Terpinene (10)	11.7	19.4	22.7	0.4	0.3
-Linalool (11)				0.5	0.7	0.7	0.4	0.4	0.5
Terpinolene (12)	0.3	0.3	0.5
cis-Mentha-2,8-dien-1-ol (13)				0.1	0.1
Isopulegol (14)				0.1	0.1	0.1
Decanal (15)				0.4	0.5	0.9	0.2	0.3	0.4
-Terpineol (16)	0.1	0.1	0.2
cis-Carveol (17)				0.1	0.1
-Citral (18)	1.1	1.3	2.7	0.1	0.1
-Citral (19)	2.0	2.2	4.8					0.1	0.2
D-Carvone (20)				0.1	0.1
Nerol (21)	0.3	0.4	0.7
Neryl acetate (22)	0.1	0.2	0.4
-Copaene (23)				0.2	0.2	0.3
-Copaene (24)				0.1	0.1	0.2
-Bergamotene (25)	0.3	0.4	1.0
Germacrene D (26)				0.1	0.1	0.1
-Bisabolene (27)	0.4	0.6	1.3
-Cadinene (28)				0.1	0.1	0.2