AOAC Method 2012.13: GC Analysis of Fatty Acids in Powdered Infant Formula on SP®-2560
CONDITIONS
sample/matrix
weigh 168 mg powdered infant formula (approximately 50 mg of fat) into a 25 mL centrifuge tube; add 2 mL of water and mix to dissolve; (let sit for 15 minutes at room temperature; add 5 mL of internal standard (C11:0 FAME + C13:0 TAG, each at 2 mg/mL in methyl tert butyl ether))
extraction
5 mL of 5% (w/v) methanolic sodium methoxide solution; close tube and vortex for 10 seconds; after 180 seconds (time starts when sodium methoxide is added) add 2 mL of hexane; (after 210 seconds add 10 ml of neutralization solution (10% disodium hydrogen citrate/15% sodium chloride in water); gently shake using vortex mixer; centrifuge mixture at 1750 rpm for 5 minutes)
eluate post-treatment
transfer 200 μL of supernatant into 10 mL flask and dilute to mark with hexane
column
SP-2560, 100 m x 0.25 mm I.D., 0.20 μm (24056)
oven
60 °C (1 min), 15 °C/min to 165 °C (1 min), 2 °C/min to 225 °C (20 min)
inj. temp.
250 °C
detector
FID, 250 °C
carrier gas
helium, 0.8 mL/min
injection
1μL, 10:1 split
liner
4 mm I.D., split/splitless type, wool packed single taper FocusLiner™ design
Description
Analysis Note
The nutritional content of infant formula is extremely critical, and thus is one of the most regulated food products worldwide. Most commercial infant formulas are derived from cow′s milk, and are formulated to mimic human breast milk. They offer the advantage of being nutritionally balanced and easy for most babies to digest. All infant formulas, whether cow′s milk-based or from another source, are subject to specific regulatory nutritional content requirements. AOAC Method 2012.13 using a 100 m SP-2560 is able to provide identification of fatty acids, as well as determination of total fatty acid content and breakdown by class.
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