Determination Of Trace Metals In Complex Matrix Samples By ICP-MS

Trace metals are essential to the process of human life and play an important role in normal growth and development,but excessive intake may also have great harm to people's health.Therefore,it is necessary to establish a rapid,efficient and sensitive method for trace metal determination.ICP-MS is a young analytical technique developed since 1980.It has been widely used in trace analysis,ultra-trace analysis and isotope analysis,which is the preferred method for the determination of trace metal elements.Although ICP-MS has many advantages in the process of element analysis,it also has some disadvantages,such as the high requirement of sample matrix.The determination of samples with complex matrix is greatly affected by matrix effect.Furthermore,some samples with complex matrix can not be detected by ICP-MS directly,such as high salt or strong alkali samples.In this paper,samples were pretreated by different methods,and trace metals in various samples were successfully detected.The main contents of the experiment are as follows:1 Ten metal elements in Magnolia officinalis from 5 different habitats were determined by ICP-MS after the wet digestion of samples.The effects of different acid system and acid dosage on the determination results were investigated.The final digestion systems were 7mL HNO₃ and 4mL HClO₄.The method has good linearity,low detection limit and good reproducibility.The accuracy of the method was verified by standard reference material and standard recovery test.The results were satisfactory.There were significant differences in the content of metal elements in Magnolia officinalis from different areas,and some heavy metal elements exceeded the standard.This method provides a reference for the study of pharmacological action of inorganic elements and the limit standard of heavy metals in Magnolia officinalis.2 An online flow injection electrodeposition system was designed.The three electrode system,consisting of a gold wire working electrode,a Pt auxiliary electrode,and an Ag/AgCl?solid?reference electrode was used.The target element in the strong alkali sample was separated from the sample matrix by electrochemical deposition,and then determined by ICP-MS.The effects of deposition potential and flow injection rate were investigated.The results showed that the optimal deposition potential is-1.4V and the optimal flow injection rate is 1.00mL·min^-1.The method has been successfully applied to the determination of Co and Cd in strong alkali samples with good linear relationship and high accuracy.It provides a reference for the evaluation of separation effect of arsenic removal from copper smelting ash by alkali leaching.3 For the first time,the electromembrane extraction technology was combined with ICP-MS to determine rare earth elements in ultrapure water.The rare earth elements in ultrapure water were enriched by electromembrane extraction and then determined by ICP-MS.The conditions such as extraction voltage,extraction time and stirring rate were optimized.Under optimal experimental conditions,the method has good linearity and high sensitivity in the range of 1¹00 ng·L^-1.This method provides a new way for the determination of rare earth elements in water samples,and it can be applied to determine ultratrace elements,which are below the LOD of ICP-MS with direct injection.