The GC analysis of fatty acids as their methyl esters derivatives (FAMEs) is an important tool in the determination of total fat and trans-fat content in foods [1, 2]. It also has an increasingly important role to play in quantifying nutritionally beneficial polyunsaturated fatty acids (PUFAs). These include the Omega-3 and Omega-6 fatty acids EPA, DHA, and ARA.
FAMEs are normally analyzed on columns coated with polar stationary phases. Doing so enables separation of fatty acids according to their carbon number, the degree of unsaturation, the cis-trans configuration, and the location of the double bonds. For GC users, the choice of stationary phases and other column dimensions such as column length, internal diameter, and film thickness can vary. It depends mainly on the complexity of the fatty acid composition and the requirements in separation detail.
Using a typical column for FAME analysis such as the 100 m Agilent J&W CP-Sil 88 column, the analysis can take over an hour. For the demanding lab environments and commercial goals of today’s food and beverage manufacturing industry, it makes analysis potentially impractical. However, by choosing the right column for the application and / or using the principles of fast GC, significant time savings and efficiency gains can be achieved.
Read on for our top tips on selecting the right column for your FAME analysis.
For detailed analysis of cis- and trans- positional isomers in the C6–C26 range
(e.g. those found in partially hydrogenated vegetable oil or CLA found in beef)
- Faster analysis (~57 minutes)
- High resolution and selectivity
For fast analysis of the most common nutrition labeling FAMEs
Choose the Agilent J&W DB-23 (20 m × 0.18 mm i.d × 0.20 μm df). It will give you:
- Faster analysis (~7 minutes)
- No coelutions
- Good resolution even for challenging cis-trans FAME isomers
Not suitable for high detail analysis of positional geometric isomers.
For a good balance between sample capacity and fast analysis times, use the 30 m × 0.25 mm i.d. × 0.25 μm df DB-23 column with hydrogen as carrier gas. To achieve results in as little as 20 minutes, without sacrificing on column capacity.
For partially hydrogenated vegetable oil (trans fat) analysis
Choose Agilent J&W Select FAME. It will give you:
- Available in 200 m version for highly detailed analysis of cis-trans FAME isomers
- The highest maximum operating temperature among high content cyanopropyl columns
- Complementary selectivity to CP-Sil 88 for FAME/HP 88
For fish oil and animal fat FAMEs (including Omega-3 and -6)
Choose the new Agilent J&W DB-FATWAX Ultra Inert. It will give you:
- Good reproducibility
- Superior inertness for difficult samples
- Ability to analyze FAMEs and fatty acids in the same column (does not require acid-modified wax phase)
- More thermostable and better operating temperatures than acid-modified wax phases
Agilent’s proprietary Ultra Inert technology makes DB-FATWAX UI the only WAX-type phase that is able to offer symmetric peaks for even challenging polar compounds such as free fatty acids. This feature improves inertness, thermal stability, and column lifetime compared to traditional WAX columns.
Selecting the right column for your FAME analysis can have considerable impact on time, cost, and productivity. If you are concerned about the time it might take you developing new methods, Agilent’s method translation software does all of the work for you. It’s easier than ever to run the most effective column for your sample, every time.
For more information about the new Agilent J&W DB-FATWAX UI column, including application notes click here.