双位加热消解—电感耦合等离子体质谱法同时测定树仔菜中7种元素的含量

Simultaneous determination of the contents of seven elements in Sauropus androgynus by double control heating and digestion-inductively coupled plasma mass spectrometry

【目的】研究双位加热消解—电感耦合等离子体质谱(双位加热消解—ICP-MS)的前处理和检测方法,并测定树仔菜中7种元素含量,建立一种测定树仔菜元素的简便、高效、准确方法,为科学开发树仔菜提供参考依据。【方法】比较分析双位加热消解—ICP-MS和微波消解—ICP-MS的空白背景值、检出限、准确度和精密度,考察消解条件(消解温度、赶酸温度和消解时间)对测定树仔菜中铜含量的影响,并通过正交试验确定最佳消解条件,建立双位加热消解—ICP-MS测定树仔菜中铅、镉、铬、砷、镍、铜和锌7种微量元素含量的方法。【结果】双位加热消解—ICP-MS和微波消解—ICP-MS的空白值与检出限均较低,但双位加热消解—ICP-MS测定的元素铬、镍、铜和锌检出限均低于微波消解—ICP-MS,差异达极显著水平(P<0.01,下同)。微波消解—ICP-MS测定标准物质GSB-26芹菜、GSB-12豆角和GSB-13蒜粉的准确度及精密度的相对标准偏差(RSD)≤5.0%;双位加热消解—ICP-MS准确度和精密度的RSD≤2.6%,低于微波消解—ICP-MS,差异达极显著水平,且测定结果更接近标准值。消解温度130℃下消解2.0 h后赶酸温度200℃为双位加热消解树仔菜的最佳消解条件,在此消解条件下ICP-MS测得树仔菜中铅、镉、铬、砷、镍、铜和锌7种元素含量分别为0.0790、0.0404、0.0350、0.00560、1.16、1.18和7.88 mg/kg。【结论】双位加热消解—ICP-MS具有操作简便、快速、检出限低、准确度和精密度高等优点,适用于树仔菜中铅、镉、铬、砷、镍、铜和锌含量的同时测定。

【Objective】To build a quick,effective,accurate detection method to detect seven heavy metal elements contents of Sauropus androgynus(SA)by researching preparation methods and detection methods of double control heating and digestion-inductively coupled plasma mass spectrometry method(DCD-ICP-MS),which could provide reference for development of S.androgynus.【Method】Blank value,detection limit,accuracy and precision of DCD-ICP-MS and microwave digestion ICP-MS method(MD-ICP-MS)were analyzed,effects of copper(Cu)content in S.androgynus at different digestion conditions such as digestion temperature,remove acid temperature and digestion time were investigated,and through orthogonal experiment the digestion conditions were optimized.A method of the determination of lead(Pb),cadmium(Cd),chromium(Cr),arsenic(As),nickel(Ni),Cu,zinc(Zn)contents in S.androgynus by DCD-ICP-MS was established.【Result】The results showed that the blank value and detection limit(DL)of DCD-ICP-MS and MD-ICP-MS were low,but the DL of Cr,Ni,Cu and Zn detected by DCD-ICP-MS were lower than by MD-ICP-MS,and the difference was extremely significant(P<0.01,the same below).The relative standard deviation(RSD)of accuracy and precision of standard substance GSB-26 celery,GSB-12 bean,GSB-13 garlic powder by MD-ICP-MS were≤5.0%,RSD of accuracy and precision by DCD-ICP-MS was≤2.6%,which was less than MD-ICP-MS,and results were closer to the standard value,the difference was extremely significant.The optimum digestion conditions of S.androgynus by DCD-ICP-MS were digestion temperature of 130℃for 2.0 h and remove acid temperature of 200℃.At these optimum conditions,the contents of Pb,Cd,Cr,As,Ni,Cu,Zn in S.androgynus were 0.0790,0.0404,0.0350,0.00560,1.16,1.18,7.88 mg/kg,respectively.【Conclusion】The DCD-ICP-MS method is simple,rapid,accurate and sensitive with low DL.It is suitable for the simultaneous determination and analysis of Pb,Cd,Cr,As,Ni,Cu,Zn of S.androgynus.