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    高效液相色谱-氢化物发生-原子荧光光谱法测定富硒食品中5种形态硒的含量

    HPLC-HG-AFS Determination of 5 Species of Selenium in Foodstuffs Rich in Selenium

    • 摘要: 提出了将高效液相色谱-氢化物发生-原子荧光光谱法应用于富硒食品中硒的形态分析。选择木瓜蛋白酶(PP)作为提取剂,在如下优化条件下对样品中5种形态硒进行提取:1料液比1 g/40 mL;2 50.0 g·L-1 PP溶液加入量20 mL;3于60℃水浴中振荡提取8 h。提取液冷却并离心后取其上清液,用Hamilton PRP-X100离子交换色谱柱作为固定相,35 mmol·L-1磷酸氢二铵溶液(pH 6.0)作为流动相进行高效液相色谱的分离,5种形态硒Se (Ⅵ)、Se (Ⅳ)、硒代胱氨酸(SeCys2)、甲基-硒代半胱氨酸(MeSeCys)和硒代蛋氨酸(SeMet)在16 min内完全分离。将分离所得分别含有5种形态硒的溶液先后引入仪器进行氢化物发生-原子荧光光谱法测定。结果表明:5种形态硒的质量浓度均在5~100 μg·L-1内与其对应的峰面积呈线性关系,5种形态硒的检出限(3S/N)为0.39~1.18 μg·L-1。按所提出方法对富硒大米样品进行加标回收和精密度试验,测得回收率为80.2%~118%,测定值的相对标准偏差(n=6)为2.1%~8.2%。

       

      Abstract: It was proposed to apply HPLC-HG-AFS to speciation analysis of selenium in foodstuffs rich in selenium. Papain (PP) was selected as extractant to separate 5 species of selenium from the sample under the following optimized conditions:① ratio of sample to solution was 1 g/40 mL; ② amount of 50.0 g·L-1 PP solution added was 20 mL; ③ extracted in a water bath at 60℃ for 8 h. The extract was cooled, centrifuged, and the supernatant was taken for HPLC separation, using Hamilton PRP-X100 chromatographic column of ion exchange as stationary phase, and 35 mmol·L-1 (NH4)2HPO4 solution (pH 6.0) as mobile phase. The 5 species of seleniumSe(Ⅵ), Se(Ⅳ), SeCys2, MeSeCys and SeMet were separated clearly within 16 min. The solutions containing separately the 5 species of selenium were then used for determination of selenium by HG-AFS. As shown by the results, linear relationships were obtained between values of peak area and mass concentrations of the 5 species of selenium in the same range of 5 to 100 μg·L-1. Values of detection limits (3S/N) for the 5 species of selenium were between 0.39 to 1.18 μg·L-1. Tests for recovery and precision were made by addition of standard solutions to the sample of rice rich in selenium, giving values of recovery ranged from 80.2% to 118%, and RSD's (n=6) ranged from 2.1% to 8.2%.

       

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