硝酸湿式消解-石墨炉原子吸收光谱法测定大米中镉含量
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摘要
采用硝酸湿式消解法测定大米中镉的含量,并与传统的硝酸-高氯酸湿式消解法和干法灰化法进行比较,确定了最佳的测定条件:灰化过程温度分为400℃和500℃两个步骤、原子化温度为1600℃、基体改进剂为硝酸钯(0. 1%,自动加样5μL)。结果表明:采用硝酸湿式消解法测定湖南大米粉(GBW10045)和大米粉(GBW10010)中镉含量,整个消解过程用时最短,为30 min,且无需赶酸,其检测结果的平均值最接近标物证书保证值中值,准确度最高;采用标准加入法绘制的镉标准工作曲线,其线性相关系数为0. 9999,斜率为0. 05973;全程用酸量低于1 m L,等同与干法灰化法。该消解法具有消解速度快、操作简便、准确度高等特点,能降低试剂消耗和减少前处理过程对环境的污染。
In this study,nitric acid wet digestion method was used to determine the content of cadmium( Cd) in Rice,and was compared with the nitric acid-perchloric acid wet digestion and dry-ash methods. The best measurement conditions were determined as follows: the ashing process temperature was divided into two steps of400 °C and 500 ° C,the atomization temperature was 1 600 ° C,and the matrix modifier was palladium nitrate( 0. 1%,automatic sample addition 5 μL). The results showed that the content of Cd in Hunan rice flour( GBW10045) and rice flour( GBW10010) was determined by the nitric acid wet digestion method,which the entire digestion process was the shortest( 30 min) and did not need to catch acid,as well as the accuracy of the test results was the highest,and the average value was closest to the median value of the guaranteed value of the standard certificate. The Cd standard working curve was drawn by the standard addition method,the linear correlation coefficient was r = 0. 9999,and the slope was 0. 05973. The digestion process used less than 1 m L of acid,the same as the dry-ash method. This digestion method has the characteristics of rapid digestion,simple operation,high accuracy,reducing reagent consumption and the environment pollution of the pre-treatment process.
In this study,nitric acid wet digestion method was used to determine the content of cadmium( Cd) in Rice,and was compared with the nitric acid-perchloric acid wet digestion and dry-ash methods. The best measurement conditions were determined as follows: the ashing process temperature was divided into two steps of400 °C and 500 ° C,the atomization temperature was 1 600 ° C,and the matrix modifier was palladium nitrate( 0. 1%,automatic sample addition 5 μL). The results showed that the content of Cd in Hunan rice flour( GBW10045) and rice flour( GBW10010) was determined by the nitric acid wet digestion method,which the entire digestion process was the shortest( 30 min) and did not need to catch acid,as well as the accuracy of the test results was the highest,and the average value was closest to the median value of the guaranteed value of the standard certificate. The Cd standard working curve was drawn by the standard addition method,the linear correlation coefficient was r = 0. 9999,and the slope was 0. 05973. The digestion process used less than 1 m L of acid,the same as the dry-ash method. This digestion method has the characteristics of rapid digestion,simple operation,high accuracy,reducing reagent consumption and the environment pollution of the pre-treatment process.
引文
[1]李裕,张强,王润元,等.镉的致癌性与食品中镉的生物有效性[J].生命科学,2010,22(2):179-184.
[2]中华人民共和国国家卫生和计划生育委员会. GB 5009. 15—2014食品安全国家标准食品中镉的测定[S].北京:中国标准出版社,2015.
[3]孙有娥,程春艳,李一辰,等.原子吸收光谱法测定大米中镉含量时试样消解方法的影响[J].化学工程与装备,2015(11):210-212.
[4]季澜洋,徐春峰.石墨炉原子吸收光谱法测定大米中的铅和镉[C].珀金埃尔默:原子光谱用户论文集,2013.
[5]中国国家标准化管理委员会. GBT 27404—2008实验室质量控制规范食品理化检测[S].北京:中国标准出版社,2009.
[2]中华人民共和国国家卫生和计划生育委员会. GB 5009. 15—2014食品安全国家标准食品中镉的测定[S].北京:中国标准出版社,2015.
[3]孙有娥,程春艳,李一辰,等.原子吸收光谱法测定大米中镉含量时试样消解方法的影响[J].化学工程与装备,2015(11):210-212.
[4]季澜洋,徐春峰.石墨炉原子吸收光谱法测定大米中的铅和镉[C].珀金埃尔默:原子光谱用户论文集,2013.
[5]中国国家标准化管理委员会. GBT 27404—2008实验室质量控制规范食品理化检测[S].北京:中国标准出版社,2009.