restekadv07 - page 184

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by RebeccaWittrig, Ph.D., Food, Flavor, &Fragrance Innovations Chemist
AnalyzingFattyAcidMethyl Esters
(FAMEs) byGC
Using Restek Capillary Columns and
Analytical ReferenceMaterials
✔ Resolve individual cis and trans isomers on our new 100-meter Rt-2560 column.
✔ Separate saturated/unsaturated FAMEs on a FAMEWAX™ column.
✔ New Food Industry FAMEMix includesmethyl esters of 37 common fatty acids in
animal, vegetable, andmarine oils.
✔ Use new qualitative cis/trans FAMEMix to identify C18:1 isomers.
Fatty acidmethyl ester (FAME) analyses are an
important tool for characterizing fats and oils and for
determining the total fat content in foods. A new cap-
illary GC column and three new referencemixtures
fromRestek can help you obtain the best results for
these challenging assays.
Individual cis and trans isomers of unsaturated
FAMEs, such as octadecenoic acid (C18:1) or
octadecadienoic acid (C18:2), are resolvedon an
Rt-2560 column—our new100-meter
biscyanopropyl phase column. An analysis of C18:1
cis and trans isomers is shownonpage 9of this
Advantage. The ability to resolve these isomersmakes
anRt-2560 column the columnof choice for analyz-
ing partially hydrogenated fats andoils; the column
meets the requirements of AOACMethod996.06.
Figure 1 shows a separationof 37 FAMEs commonly
encounteredby foodquality chemists, obtainedby
using anRt-2560 column.
GC_FF00649
Column: Rt-2560, 100m, 0.25mm ID, 0.2µm
(cat.# 13199)
Sample: 30mg/mL total FAMEs inmethylene chloride
Inj.: 2.0µL split (split ratio 200:1), 4mm inlet
liner (cat.# 20814)
Inj. temp.: 225°C
Carrier gas: hydrogen, constant flow
Flow rate: 1.2mL/min.
Oven temp.: 100°C (4min. hold)
to 240°C@ 3°C/min. (10min. hold)
Det.: FID@ 250°C
Compound % inMix
1. C4:0 methyl butyrate 4.0
2. C6:0 methyl hexanoate 4.0
3. C8:0 methyl octanoate 4.0
4. C10:0 methyl decanoate 4.0
5. C11:0 methyl undecanoate 2.0
6. C12:0 methyl laurate 4.0
7. C13:0 methyl tridecanoate 2.0
8. C14:0 methyl myristate 4.0
9. C14:1 methyl myristoleate ( cis-9) 2.0
10. C15:0 methyl pentadecanoate 2.0
11. C15:1 methyl pentadecenoate ( cis-10) 2.0
12. C16:0 methyl palmitate 6.0
13. C16:1 methyl palmitoleate ( cis-9) 2.0
14. C17:0 methyl heptadecanoate 2.0
15. C17:1 methyl heptadecenoate ( cis-10) 2.0
16. C18:0 methyl stearate 4.0
17. C18:1 methyl elaidate ( trans-9) 2.0
18. C18:1 methyl oleate ( cis-9) 4.0
19. C18:2 methyl linoleaidate ( trans-9,12) 2.0
20. C18:2 methyl linoleate ( cis-9,12) 2.0
21. C18:3 methyl γ-linolenate ( cis-6,9,12) 2.0
22. C20:0 methyl arachidate 4.0
23. C20:1 methyl eicosenoate ( cis-11) 2.0
24. C18:3 methyl linolenate ( cis-9,12,15) 2.0
25. C21:0 methyl heneicosanoate 2.0
26. C20:2 methyl eicosadienoate ( cis-11,14) 2.0
27. C20:3 methyl eicosatrienoate ( cis-11,14,17) 2.0
28. C22:0 methyl behenate 4.0
29. C22:1 methyl erucate ( cis-13) 2.0
30. C20:3 methyl eicosatrienoate ( cis-11,14,17) 2.0
31. C20:4 methyl arachidonate ( cis-5,8,11,14) 2.0
32. C23:0 methyl tricosanoate 2.0
33. C22:2 methyl docosadienoate ( cis-13,16) 2.0
34. C20:5 methyl eicosapentaenoate 2.0
( cis-5,8,11,14,17)
35. C24:0 methyl lignocerate 4.0
36. C24:1 methyl nervonate ( cis-15) 2.0
37. C22:6 methyl docosahexaenoate 2.0
( cis-4,7,10,13,16,19)
For analyzingmixtures of saturated andunsaturated
fatty acidmethyl esters, stationary phases consisting
of polyethylene glycol (e.g., Carbowax®) typically are
used. FAMEWAX™ columns offer excellent selectivity
for analyses of polyunsaturated fatty acids. The poly-
ethylene glycol stationary phase is especially capable
of resolvingOmega-3polyunsaturated FAMEs, such as
eicosapentenoic acid (C20:5) anddocosahexenoic
acid (C22:6). FAMEWAX™ columns combine excellent
resolutionof polyunsaturated FAMEswith significantly
reduced analysis times, compared to traditional
Carbowax® stationary phases.
In addition to our newRt-2560 capillary column
for cis and trans isomers analysis, we are introduc-
ing three new FAMEsmixtures to support food and
nutraceuticals testing. Our 37-component Food
Industry FAMEMix is a complete profile of the
common fatty acids in animal, vegetable, and
marine oils, includingmany polyunsaturated
FAMEs, such as C20:5 and C22:6. Figure 1 is a
chromatographic separation of thismix. NewNLEA
FAMEMix was designedwith AOACMethod 996.06
inmind; it can be used as the calibration standard
for this Fat by Fatty Acid Compositionmethod. Use
our qualitative cis/trans FAMEMix to identify the
cis and trans isomers of octadecenoic acid
(C18:1). For descriptions and ordering information
for the latter twomixes, and an analysis of the
cis/trans FAMEMix, see page 9.
Before you attempt to characterize a fat or oil, contact
Restek for capillary columns and referencematerials
that canhelp youobtain the data youneed.
Figure 1
37-Component Food Industry FAMEMix includes common components of animal, vegetable,
andmarine oils.
Ordering Information | Rt-2560Column (FusedSilica)
Component
C4:0
C6:0
C8:0
C10:0
C11:0
C12:0
C13:0
C14:0
C14:1( cis-9)
C15:0
C15:1( cis-10)
C16:0
C16;1( cis-9)
C17:0
C17:1( cis-10)
C18:0
C18:1( trans-9)
C18:1( cis-9)
C18:2(all- trans-9.12)
Component
C18:2(all- cis-9,12)
C18:3(all- cis 6,9,12)
C18:3(all- cis 9,12,15)
C20:0
C20:1( cis-11)
C20:2(all- cis 11,14)
C20:3 (all- cis8,11,14)
C20:3(all- cis 11,14,17)
C20:4(all- cis 5,8,11,14)
C20:5 (all- cis5,8,11,14,17)
C21:0
C22:0
C22:1( cis13)
C22:2(all- cis 13,16)
C22:6 (all- cis4,7,10,13,16,19)
C23:0
C24:0
C24:1( cis-15)
In methylene chloride, 1mL/ampul. For concentrations, see
Figure 1.
Food Industry FAMEMix (37 components)
ea.
35077
Descriptions and ordering
information for our NLEA
and cis/trans FAMEsmixes
are on page 9 of this
Advantage.
Ordering Information | FAMEWAX™ Columns (FusedSilica)
ID df (µm) temp. limits 30-Meter
0.25mm 0.25 20 to 250°C 12497
0.32mm 0.25 20 to 250°C 12498
0.53mm 0.50 20 to 250°C 12499
ID df (µm) temp. limits 100-Meter
0.25mm 0.20 20 to 250°C 13199