富硒蛹虫草中有机硒的分析

摘要

An effective method was developed for the determination of organic selenium in selenium-enriched Cordyceps militaris by high resolution-continuum source graphite furnace atomic absorption spectrophotometry (HR-CS GFAAS). The samples were pretreated according to the standard of DBS42/002-2014 and GB 1903.21-2016,respectively.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,and the best ashing temperature was 1 100℃,the best atomization temperature was 2 200℃by single factor experiments.Further determination of selenium under the condition of the above,the result showed that the total selenium in selenium-enriched cordyceps militaris was 1.407 mg/g, and the inorganic selenium were 0.083 mg/g. The organic selenium in selenium-enriched cordyceps militaris was 1.324 mg/g by calculating,and had reached 94.1 % of total selenium.These indicate that the selenium-enriched cordyceps militaris contain rich organic selenium and are good filling selenium products. The recoveries for total selenium and inorganic selenium were 95.7 % and 94.0 % respectively, relative standard deviation were less than 4.5 %. 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.%建立高分辨-连续光源石墨炉原子吸收光谱法(high resolution-continuum source graphite furnace atomic absorption spectrophotometry,HR-CS GFAAS)测定富硒蛹虫草中有机硒的方法.参照DBS42/002-2014《湖北省食品安全地方标准富有机硒食品硒含量要求》制备富硒蛹虫草总硒测定试样,参照GB 1903.21-2016《食品安全国家标准食品营养强化剂富硒酵母》制备富硒蛹虫草无机硒测定试样,再使用HR-CS GFAAS测定富硒蛹虫草总硒和无机硒.试验以Pd(NO3)2(1 g/L)和Mg(NO3)2(0.5 g/L)混合溶液为基体改进剂,通过试验优化出基体改进剂最佳添加体积为5 μL,最佳灰化温度为1100℃,最佳原子化温度为2200℃.测定结果表明,富硒蛹虫草总硒含量为1.407 mg/g,无机硒含量为0.083 mg/g,计算出有机硒含量为1.324 mg/g,所占百分比为94.1 %,这说明富硒蛹虫草含有丰富的有机硒,是补硒良品.总硒和无机硒的加标回收率分别为95.7 %和94.0 %,相对标准偏差<4.5 %.该方法快速、准确、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.