Characterization of Essential Oils
- Chromatography peaks tell you when and how much compound you have.
- The Mass Spectrum shows you the compounds fragmentation pattern, which acts as a molecular finger print.
- The Kovats Index, provides a dimensionless unit for comparison with other databases.
Table Showing GC:MS Analysis Of 2 Oils: Citronella oil and lemon oil:
Citronella Oil |
Lemon Oil |
||
GC: Retention time |
Compound Name |
GC: Retention time |
Compound Name |
6.509 |
Limonene |
5.099 |
alpha Thujene |
7.427 |
Linalool |
5.197 |
alpha Pinene |
8.037 |
neoiso-Isopulegol |
5.411 |
Camphene |
8.098 |
Citronellal |
5.769 |
Sabinene |
8.177 |
Isopulegol |
5.816 |
beta Pinene |
8.981 |
Citronellol |
5.994 |
Myrcene |
9.291 |
Geraniol |
6.470 |
o-Cymene |
9.495 |
Geranial |
6.517 |
Limonene |
10.382 |
Citronellyl Acetate |
6.929 |
gamma Terpinene |
10.474 |
Eugenol |
7.304 |
alpha Terpinolene |
10.705 |
Geranyl Acetate |
7.430 |
Linalool |
10.876 |
beta Elemene |
7.489 |
Nonanal |
11.755 |
Napthalene |
7.882 |
cis-Limonene oxide |
11.83 |
beta Cubebene |
7.937 |
trans-Limonene oxide |
11.989 |
alpha Muurolene |
8.027 |
Epoxyterpinolene |
12.215 |
delta Cadinene |
8.101 |
Citronellal |
12.466 |
Hedycaryol |
8.433 |
Terpinen-4-ol |
12.749 |
endo-1-bourbonanol |
8.587 |
alpha Terpineol |
13.274 |
Guaiol |
9.163 |
Citral |
13.476 |
T-Muurolol |
10.506 |
Neryl Acetate |
Kovats Index (KI)
- A dimensionless quantity that characterizes each GC:MS eluted compound, according to a linear retention index and eradicates instrument variations e.g. oven temperature, gas flow etc. but not column differences.
- The retention times of a known C7-C40 alkane standard is used to calibrate KI.
- We have a software program that then generates the KI from the retention times of the standard alkane above and below the analyte of interest .