反相离子对高效液相色谱法测定铁强化酱油中的乙二胺四乙酸铁钠

Determination of Sodium Iron(Ⅲ) Ethylenediaminetetraacetate in Iron-Fortified Soy Sauce by Reversed-Phase Ion-Pair High Performance Liquid Chromatography

建立了用反相离子对高效液相色谱法分离和测定铁强化酱油中的铁营养强化剂乙二胺四乙酸铁钠（NaFeEDTA）的方法。样品经甲醇沉淀后，以Zorbax C8色谱柱（150mm×4．5mmi．d．，5μm）进行分离，以含12．5％甲醇、0．13％四丁基氢氧化铵（TBAOH）和0．052％甲酸的水溶液（pH3．5）作为流动相，流速为1．00mL／min，检测波长为254nm，整个分离过程在30min内完成。考察了NaFeEDTA在不同品牌酱油中的回收率，其中NaFeEDTA的添加量为0．50～4．00g／L时，其回收率为94．15％～101．5％。对NaFeEDTA添加量为2．00g／L的铁强化酱油样品重复测定5次，其峰面积的相对标准偏差为0．89％。NaFeEDTA标准溶液的最低检测限为0．03mg／L。本方法简单、快速、重现性好，可用于铁强化酱油中NaFeEDTA含量的检测。

A novel reversed-phase ion-pair high performance liquid chromatographic method was developed for separation and determination of sodium iron （ Ⅲ ） ethylenediaminetetraacetate （NaFeEDTA） in iron-fortified soy sauce. Sample treatment and chromatographic conditions were investigated. After precipitation by methanol, the sample was separated on a Zorbax Cs column （150 mm ×4.5 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 5 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.