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5
Stabilwax
®
-DAColumns for Acidic Compounds
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
· Ideal for free fatty acids analysis.
· Thermally stable to 250°C.
· Solvent rinsable.
· Resolves saturated andunsaturated free fatty acids.
· No derivatizationneeded of free fatty acids.
· Inertness increases sample capacity.
· Achieves good peak shapes.
The analysis of volatile free fatty acids has beendifficult on common siloxane
stationary phases because of analyte adsorption and low sample capacity.
Although PEG stationary phases exhibit improved capacity and better selec-
tivity formany freeacids,peak tailingstill canoccur.Stabilwax
®
-DA isabonded
PEG stationary phase that has been specially deactivated to analyze acidic
compounds. The resulting inertness significantly reduces adsorption and in-
creases sample capacity of volatile-free acids, thereby improving peak shape
(
Figure 4
). It also eliminates the need to derivatize free fatty acids fromC1 to
C20, which simplifies sample preparation. Restek’s deactivation and innova-
tive Crossbond
®
procedure produces columns that last longer and give better
peak shapes with high molecular weight acids than our
competitors.
2
9
8
7 6
4
3
1
13
Figure 4
Stabilwax
®
-DAColumnGivesGood Peak Shapes for Free FattyAcids
30m, 0.53mm ID, 0.25µmStabilwax
®
-DA (cat.#11025)
0.5µl direct injection of a5mg/ml standard.
Oven temp.:
100°C (hold2min.) to 250°C@8°C/min.;
Inj. & det. temp.:
280°C;
Carrier gas:
helium;
Linear velocity:
40cm/sec. (flow rate: 5.2cc/min.);
FID sensitivity:
8 x 10
-11
AFS
1. C2:0 - acetic acid
2. C3:0 - propionic acid
3. C4:0 - butyric acid
4. C5:0 - valeric acid
5. C6:0 - caproic acid
6. C7:0 - enanthic acid
7. C8:0 - caprylic acid
8. C10:0 - capric acid
9. C12:0 - lauric acid
10. C14:0 - myristic acid
11. C15:0 - pentadecanoic acid
12. C16:0 - palmitic acid
13. C16:1 - palmitoleic acid
14. C18:0 - stearic acid
15. C18:1 - oleic acid
16. C18:2 - linoleic acid
17. C18:3 - linolenic acid
17
16
15
14
12
11
10
min. 4
8
12
24
20
16
c-gram #162
5
Special deactivation
improves separations
and simplifies sample
preparation.
Restek’s Crossbond
®
Procedure produces
columns with lower
bleed, longer lifetime,
solvent rinsability,
andyoucanusedirect
acqueous injections.
