富硒有机肥对大蒜中硒元素及其形态的影响

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

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(NO_3)_2(1 g/L)和Mg(NO_3)_2(0.5 g/L)混合溶液,且最佳添加体积为5μL。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8.933~9.476μg/g,无机硒含量为5.784~6.021μg/g,计算出有机硒含量为3.124~3.491μg/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。

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. 491μg/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.