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17
Figure 20A
Linalool and linalool oxides in lavender oils are stereochemically
separated on the Rt-
β
DEXsm column.
Figure 20B
The
Rt-
β
DEXse column resolves enantiomers of
linalyl acetate in lavender oils.
20
min. 10
30
40
50
20
min. 10
30
40
50
1a. (-)-limonene
1b. (+)-limonene
2. (+)-trans-linalool oxide
3. (-)-cis-linalool oxide
4a. (-)- (R)-linalool
4b. (+)-(S)-linalool
5. (+/-)camphor
6. R,S linalyl acetate
1b
2 3
4a
5
{
6
1a
Lavender oils provided by Belmay.
Lavender oils provided by Belmay.
30m, 0.32mm ID, 0.25µmRt-
β
DEXse (cat.# 13106);
Oven temp.:
40°C (hold 1min.) to 200°C@ 2°C/min. (hold 3min.);
Carrier gas:
hydrogen; 80cm/sec.;
Detector:
FID set @ 220°C
30m, 0.32mm ID, 0.25µmRt-
β
DEXsm (cat.# 13104);
Oven temp.:
40°C (hold 1min.) to 200°C@ 2°C/min. (hold 3min.);
Carrier gas:
hydrogen; 80cm/sec.;
Detector:
FID set @ 220°C
1a. (-)-limonene
1b. (+)-limonene
2. (+)-trans-linalool oxide
3. (-)-cis-linalool oxide
4a. (-)- (R)-linalool
4b. (+)-(S)-linalool
5. (+/-)camphor
6a. (-)-(R)-linalyl acetate
6b. (+)-(S)-linalyl acetate
1a
1b + eucalyptol
2 3
4a
{
5
6a
6b
Visit Restek on-line at
,
or call 800-356-1688,
ext. 4, for technical
assistance.
LavenderOil
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
The Rt-
β
DEXsm column separates
theenantiomersof theprimarychiral
compounds found in lavender oil, in-
cluding linalool. Both the cis and
trans enantiomeric pairs of the
furanoid linalool oxides, which con-
tribute characteristic odors to laven-
der oils andClary sage oil, are sepa-
rated on this column. (R)-Linalool is
present in at least 85% enantiomeric
excess. (2R)-Configured linalool ox-
ides are present in about 77% enan-
tiomericexcess inauthenticLavender
oils.
2
Both the cis and trans (R)-lina-
lool oxides are essentially enantio-
mericallypure in thisoil, asshown in
Figure 20A
(peaks 2 and 3).
Linalyl acetate is another primary
constituent in lavender oils. The (R)-
(-) enantiomer is predominant in au-
thentic lavenderoils.
3
Adual column
system comprised of both the Rt-
β
DEXsm and Rt-
β
DEXse columns
can be used to resolve the enanti-
omers of linalyl acetate aswell (peak
6 in
Figure20B
).Note that the (-)-(R)-
enantiomer constitutes >92% of
linalyl acetate in this lavender oil.
4b
4b
