原子吸收光谱法间接测定腌制和泡制蔬菜中亚硝酸盐
Indirect Determination of Nitrites in Salted and Pickled Vegetables by AAS
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摘要: 提出了一种原子吸收光谱法间接测定腌制和泡制蔬菜中亚硝酸盐的方法.采用蒸馏水将亚硝酸盐从试样中提取分出,在pH 3.0的硫酸介质中,亚硝酸盐与高锰酸钾反应生成二氧化锰沉淀,再加入6.0 mol·L-1硫酸溶液溶解二氧化锰,通过用原子吸收光谱法测定反应中定量释出的锰量,间接换算成亚硝酸盐含量.锰的质量浓度在0.10~4.0 mg·L-1范围内与吸光度呈线性关系.在0.20 mg·g-1标准加入水平下,于试样溶液中加入标准溶液并按所述方法进行准确度和精密度试验,所得回收率在94.5%~105.0%之间,相对标准偏差(n=10)小于1.0%.Abstract: A method for indirect determination of nitrite in salted and pickled vegetables by AAS was proposed in this paper.Nitrite was extracted from sample with distilled water,and reacted with KMnO4 to precipitate MnO2 in a H2SO4 medium of pH 3.0.The precipitate of MnO2 obtained was dissolved in 6.0 mol·L-1 H2SO4 and determined by AAS,and the amount of Mn2+ found was converted into contents of nitrite.Linear relationship between values of absorbance and mass concentration of manganese was obtained in the range of 0.10-4.0 mg·L-1.Tests for accuracy and precision were made by addition of standard solutions to sample solutions at the concentration level of 0.20 mg·g-1 and analyzed by the proposed method,values of recovery in the range of 94.5%-105.0% and values of RSD′s (n=10) less than 1.0% were obtained.