食品分析中容器对铜、镉离子吸附作用的影响
Effect of the adsorption of Cu2+, Cd2+ in food analysis container
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摘要: 金属离子在分析容器上的吸附特性,使食品中痕量金属含量分析结果存在误差,了解和掌握误差来源是避免和减少分析误差的重要途径。实验利用原子吸收光谱法,对不同酸度、浓度和温度的铜、镉离子在玻璃容器和塑料容器内壁上的吸附行为进行了研究。结果表明,金属离子溶液的酸度和浓度越高、贮存温度越低,容器对离子的吸附率越低;玻璃和塑料对铜、镉离子的吸附规律明显不同,在玻璃上的吸附过程符合一级动力学模型,而在塑料上的吸附过程符合二级动力学模型;金属离子在玻璃容器中的总吸附率大于在塑料容器中的。Abstract: There is an error in analysis of trace metal content in the food beacuse of adsorption characteristics in container of metal ions, to understand and grasp the source of error is an important way to avoid and reduce the analysis error.The behavior of adsorption of Cu~ (2+) , Cd~ (2+) on the inner wall of glass and plastic vessels in solutions of different acidity, content and temperature was studied by AAS.It was showed that the higher acidity, higher content and lower temperature could reduce adsorption of metal irons.Adsorption law of Cu~ (2+) , Cd~ (2+) in the glass and plastic were significantly different.The adsorption process on the glass conforms to the first order kinetic model, and on the plastic conforms to the secondary order kinetic model.The rate of adsorption in the glass vessel was larger than that in the plastic vessel.