Food & Beverage
Analysis of Triglycerides
in Butter and Lard
Using an MET-Biodiesel GC Column
Triglycerides (also called triacylglycerol, triacylglyceride or TAG) are the
main constituent of vegetable oil and animal fat, and make up most
of the fats digested by humans. They are important in that they allow
the uptake and transport of fat-soluble vitamins. Plus, they play a role
in metabolism (unused saturated or monounsaturated fatty acids
are stored by the body as triglycerides). However, triglyceride intake
should be monitored because high levels of triglycerides have been
linked to an increased risk of heart disease and stroke.
Most natural fats contain a complex mixture of individual triglycerides.
Therefore, efficient capillary GC columns with the ability to
provide ample resolution are required for proper identification.
Triglycerides are large compounds requiring a relatively high final
oven temperature for elution in a reasonable time. The International
Organization for Standardization (ISO) specifies a reference method for
the determination of triglycerides in milk products using GC.1
Experimental
Our MET-Biodiesel capillary GC column was designed specifically for
the determination of free and total glycerin in B100 biodiesel samples.
Several features and benefits of this column indicate it is also
well-suited for the analysis of triglycerides in food products.
Figure 1. Butter Triglycerides
Chromatogram courtesy of Dr. M. Povolo and Dr. G. Contarini (CRA-FLC, Lodi, Italy)
column:
oven:
det.:
carrier gas:
injection:
sample:
1.
2.
3.
4.
5.
T26
T28
T30
T32
T34
MET-Biodiesel, 14 m x 0.53 mm I.D., 0.16 µm with
integrated 2 m x 0.53 mm I.D. guard (28668-U)
150 °C, 30 °C/min. to 350 °C (15 min.)
FID, 400 °C
helium, 15 mL/min.
1 µL, cool on-column
butter extract
6.
7.
8.
9.
10.
T36
T38
T40
T42
T44
11.
12.
13.
14.
15.
T46
T48
T50
T52
T54
4
1
2
7
6
5
8
10 12
9 11 13
14
15
3
0246 810
Min
These features and benefits include:
column holds up better than fused silica, virtually eliminating
• Metal
column breakage
guard protects the analytical column, extending column
• Integrated
life with a leak-free connection
guard also acts as a retention gap, minimizing peak
• Integrated
broadening
• Provides good peak shape and resolution for glycerides
to separate mono-, di- and triglycerides (the mono- and
• Able
diglycerides analyzed as TMS derivatives)
• Short column length, allowing for fast analysis times
at a maximum temperature of 380 °C (isothermal)
• Operates
and 430 °C (programmed)
The extraction and analysis of triglycerides in butter and lard samples
were performed, with the resulting chromatograms shown in Figure 1
and Figure 2, respectively.2 All separations were performed using cool oncolumn injection, which improves the recovery of high molecular weight
substances. Peak IDs follow the nomenclature where T## (Triglyceride
Number or Triacylglycerol Number) signifies the total number of carbons
on the fatty acid chains, regardless of degree of saturation or position
on the glycerol backbone. For example, T54 could be SSS, a triglyceride
containing three stearic acids (C18:0). It could also be SOS or SSO, a
triglyceride containing two stearic acids (C18:0) and one oleic acid (C18:1).
Figure 2. Lard Triglycerides
Chromatogram courtesy of Dr. M. Povolo and Dr. G. Contarini (CRA-FLC, Lodi, Italy)
column:
oven:
det.:
carrier gas:
injection:
sample:
MET-Biodiesel, 14 m x 0.53 mm I.D., 0.16 µm with
integrated 2 m x 0.53 mm I.D. guard (28668-U)
150 °C, 20 °C/min. to 350 °C (15 min.)
FID, 400 °C
helium, 15 mL/min.
4
1.
1 µL, cool on-column
2.
lard extract
3.
4.
5.
6.
5
3
1 2
T44
T46
T48
T50
T52
T54
6
024681012
14
Min
Food & Beverage
Results & Discussion
Featured and Related Products
The MET-Biodiesel, in combination with cool on-column injection, fast
carrier gas flow rates, rapid oven temperature ramp rates and high
final oven temperatures, was able to provide significant resolution
for both applications with relatively short run times. Table 1 lists the
column specifications. As evident, the triglyceride profile of butter is
much more complex than that of lard. The profile differences can be
attributed to the fact these products are from different sources; butter
is processed from cow milk or cream; whereas, lard is rendered from
pig fatty tissues.
Description
MET-Biodiesel GC Column
14 m x 0.53 mm I.D., 0.16 μm, with integrated 2 m x
0.53 mm I.D. guard
Analytical Standards
Triglycerides, Saturated, Even Carbon Kit,
11 individually packaged analytes
The MET-Biodiesel capillary column is a suitable choice for analysts
who work on triglyceride separations in which high column
temperatures are required. The column’s inertness, high thermal
stability and low bleed ensure good peak shape and resolution for the
analytes that were evaluated. As shown, this column can be used to
achieve optimal result for these applications.
Table 1. MET-Biodiesel Column Specifications
Application: This rugged metal column was designed specifically
for the determination of free and total glycerin in B100 biodiesel
samples. A guard is integrated, thereby providing protection with
a leak-free connection (the guard and analytical column are one
continuous piece of tubing; there is no union between the guard
and analytical column).
USP Code: None
Phase: Bonded; proprietary
Temperature Limits: -60 °C to 380/430 °C
Glycerol triarachidate, 100 mg
Glycerol trihexanoate, 1 mL
Glyceryl tributyrate, 100 mg
Glyceryl tridecanoate, 100 mg
Glyceryl tridodecanoate, 100 mg
Glyceryl trilinolenate, 100 mg
Qty.
Cat. No.
1
28668-U
1 kit
TRI11-1KT
Glyceryl trimyristate, 100 mg
Glyceryl tristearate, 100 mg
Triacetin, 100 mg
Tribehenin, 100 mg
Tripalmitin, 100 mg
Triglycerides Kit, 19 individually packaged analytes
Glycerol triarachidate, 100 mg
Glycerol trihexanoate, 1 mL
Glyceryl tributyrate, 100 mg
Glyceryl tridecanoate, 100 mg
Glyceryl tri(cis-13-docosenoate), 100 mg
Glyceryl tridodecanoate, 100 mg
Glyceryl tri(cis-11-eicosenoate), 100 mg
Glyceryl trielaidate, 100 mg
Glyceryl trilinoleate, 100 mg
Glyceryl trilinolenate, 100 mg
1 kit
TRI19-1KT
Glyceryl trimyristate, 1000 mg
Glyceryl trioctanoate, 0.5 mL
Glyceryl trioleate, 100 mg
Glyceryl tripalmitoleate, 100 mg
Glyceryl tripetroselinate, 100 mg
Glyceryl tristearate, 100 mg
Triacetin, 100 mg
Tribehenin, 100 mg
Tripalmitin, 100 mg
References
1. ISO/DIS 17678.2, Milk and Milk Products – Determination of Milk Fat Purity by
Gas Chromatographic Analysis of Triglyceride, International Organization for
Standardization.
2. M. Povolo, V. Pelizzola, and G. Contarini, Directly Resistively Heated Column Gas
Chromatography for the Evaluation of Cow Milk Fat Purity, European Journal of
Lipid Science and Technology 110.11 (2008) page 1050-1057.
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