Objective To evaluate the quantitative and qualitative detection of trans fatty acids (TFA) in processed foods with silver ion solid phase extraction-gas chromatography (Ag+-SPE/GC).
Methods The fatty acid methyl esters derived from beef ham, soybean flour and chocolate wafer were priorily separated by silver ion solid phase extraction column, and then tested with gas chromatography according to Determination of trans fatty acids in foods-Gas chromatography (GB/T 22110-2008).
Results The recoveries of TFA methyl ester isomer in food ranged from 71.0% to 90.5% with the relative standard deviation (RSD) less than 13%. The average recoveries of TFA methyl ester standard ranged from 84.1% to 98.7% with the RSD less than 5.6%. The lowest detection limit was 10 mg/100 g fat. TFA content in beef ham, soybean flour and chocolate wafer were 37.26 mg/100 g, 24.64 mg/100 g and 162.85 mg/100 g, respectively. These three types of food were high in t C18:1, second in t C18:2, low in t C18:3, and no for t C16:1.
Conclusion The Ag+-SPE/GC method, with high sensitivity and good separation and repeatability, capable to avoid the interference of cis-and saturated fatty acids, is suitable to detect TFA content in milk, meat, chocolate and their products.
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