火焰原子吸收光谱法间接测定白酒中甜蜜素
Indirect Determination of Sodium Cyclamate in White Spirit by Flame Atomic Absorption Spectrometry
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摘要: 提出了一种火焰原子吸收光谱法间接测定白酒样品中甜蜜素的测定方法.采用乙醚将甜蜜素从酸化后的白酒样品中提取出,提取液经挥发去除乙醚后加浓硝酸置于100 ℃水浴中硝化,硝化产生的硫酸根与铬酸钡悬浮液反应生成硫酸钡,通过用火焰原子吸收光谱法测定反应中定量释出的铬酸根间接换算成甜密素含量.甜蜜素的质量浓度在0.35 g·L-1以内与吸光度呈线性关系,其线性回归方程为A=0.301 ρ甜+0.018,检出限(3S/N)为0.02 g·L-1.在0.060,0.250,0.500 g·L-1的标准加入水平下进行了精密度试验,所得相对标准偏差(n=6)分别为8.93%,3.44%,3.63%.加标回收率在86.7%~105.0%之间.Abstract: A method for indirect determination of sodium cyclamate in white spirit by FAAS was studied and reported in this paper.Sodium cyclamate was extracted with ether from acidified white spirit sample.The extract was evaporated to eliminate ether and nitrified with conc.HNO3 in water bath at 100 ℃.In the course of nitration,sulfonate was displaced from the molecule of sodium cyclamate to give SO2-4 which was precipitated as BaSO4 from the solution with suspension of barium chromate.Chromate liberated in the reaction was then determined by FAAS,and the amount of chromium(Ⅵ) found was converted into contents of sodium cyclamate.Linear relationship between absorbance and mass concentration of sodium cyclamate was obtained in the range within 0.35 g·L-1,corresponding to the linear regression equation of A=0.301 ρ甜+0.018.Detection limit (3S/N) of the method was 0.02 g·L-1.Tests for precision were made by addition of 0.060,0.250,0.500 g·L-1 of the sodium cyclamate standard solution to blank wine samples,and values of RSD′s obtained were 8.93%,3.44%,3.63%.Values of recovery were found in the range of 86.7%-105.0%.