Abstract:

A novel reversed-phase ion-pair high performance liquid chromatographic method was developed for separation and determination of sodium iron (Ⅲ) ethylenediaminetetra-acetate (NaFeEDTA) in iron-fortified soy sauce. Sample treatment and chromatographic conditions were investigated. After precipitation by methanol, the sample was separated on a Zorbax C8 column (150 mm×4.6 mm i.d.,5 μm). The mobile phase was 12.5%(v/v) methanol solution containing 0.13%(v/v) tetrabutyl ammonium hydroxide and 0.052%(v/v) formic acid( pH 3.5). NaFeEDTA was detected at 254 nm. The separation was achieved within 30 min with a flow rate of 1.00 mL/min. An iron-fortified soy sauce sample containing 2.00 g/L NaFeEDTA was analyzed for 6 times, and the relative standard deviation (RSD) of peak areas of NaFeEDTA was 0.89%. The recoveries of NaFeEDTA ranged from 94.15% to 101.5% with the spiked amounts of 0.50-4.00 g/L. The detection limit of NaFeEDTA standard solution was 0.03 mg/L. This simple and rapid method with good reproducibility can be used for the determination of NaFeEDTA in iron-fortified soy sauce.

Key words: iron-fortified soy sauce , sodium iron (Ⅲ) ethylenediaminetetraacetate (NaFeEDTA), reversed-phase ion-pair high performance liquid chromatography (RIHPLC)