富硒有机肥对大蒜中硒元素及其形态的影响

建立了高分辨-连续光源石墨炉原子吸收光谱法（HR-CS GFAAS）测定富硒大蒜中不同形态硒含量的方法,研究富硒有机肥对大蒜中硒元素及其形态的影响。通过单因素试验优化得出硒元素最佳测定条件,即最佳基体改进剂为Pd（NO3）2（1 g/L）和Mg（NO3）2（0.5 g/L）混合溶液,且最佳添加体积为5 μL。参照标准DBS 42/002—2014制备出富硒大蒜总硒和无机硒测定试样,再使用HR-CS GFAAS法测定总硒含量为8.933～9.476 μg/g,无机硒含量为5.784～6.021 μg/g,计算出有机硒含量为3.124～3.491 μg/g,所占百分比为34.16%～36.84%,这说明富硒有机肥能有效提高大蒜中总硒和有机硒的含量。该方法的精密度为3.0%～5.2%,总硒和无机硒的加标回收率分别为96.3%和93.7%,这表明参照DBS 42/002—2014分析富硒大蒜中硒元素含量及其形态,结果准确可靠,添加的标样（无机硒）几乎全部在待测无机硒试样中。该方法快速、准确且稳定,具有较高的实用价值,为分析食品中微量元素含量及其形态提供科学依据。 

Effect of Selenium-enriched Organic Fertilizers on Selenium and its Form in Garlic

An effective method was developed for determination of selenium of different forms in selenium-enriched garlic by high resolution-continuum source graphite furnace atomic absorption spectrophotometry（HR-CS GFAAS）.Effect of selenium-enriched organic fertilizers on selenium and its form in garlic was studied.The mixture of Pd（NO3）2（1 g/L）and Mg（NO3）2（0.5 g/L）was selected as the matrix modifier with the best volume of 5 μL for determination of selenium by single factor experiments.The samples were pretreated according to the standard of DBS 42/002—2014,and further determination of selenium by HR-CS GFAAS,results showed that the total selenium in selenium-enriched garlic was 8.933～9.476 μg/g,and inorganic selenium in selenium-enriched garlic was 5.784～6.021 μg/g.The organic selenium in selenium-enriched garlic was 3.124～3.491 μg/g by calculating,and had reached 34.16%～36.84% of total selenium.These indicated that total selenium and organic selenium in garlic were increased effectively by using selenium-enriched organic fertilizers as garlic grow.The relative standard deviations were from 3.0% to 5.2%,and the recoveries for total selenium and inorganic selenium were 96.3% and 93.7% respectively,indicating that selenium and its form in selenium-enriched garlic by the standard of DBS 42/002—2014 could get accurate and reliable results,moreover,the added prototype（inorganic selenium）was almost all in the inorganic selenium sample.Therefore,the proposed method was rapid,accurate and stable with a high practical value.It provided scientific basis for analysis of many trace elements and their forms in food.