Development Of Solid Micro Analysis With Dielectric Barrier Discharge Technology And Its Application

Solid microregion analysis technology can provide the distribution of related elements in solid samples rapidly,efficiently and with a large amount of information,and has played a very important role in various fields.Dielectric barrier discharge?DBD?has attracted much attention because of its simple structure,easy operation,low energy consumption and large amount of active substances.When DBD micro-plasma jet effected on the surface of a solid sample,a series of physical and chemical reactions,such as charge transfer,dissociation,and oxidation reduction,would happened between the activity of high-energy particles and the solid sample,at the same time,the elements particles would been stripped out by the high-speed airflow in the DBD probe,these elements particles could be carried into the analytical instrument for detection.Based on this new principle,this paper developed an automatic DBD microregion analysis device for solid samples,studied the analytical performance of the device.A new microregion analysis method based on DBD-inductively coupled plasma mass spectrometry?ICP-MS?was proposed,and successfully applied to the elemental imaging analysis of seal impression,ceramic lead glaze and stromatolite.1.A set of DBD solid sample microregion analysis device was developed.The device is mainly composed of DBD probe system,electrically driven mobile platform system,sample cell,transmission pipeline and control system.It can precisely locate the sample analysis site visually and realize the fixed-point analysis,arbitrary path analysis and regional scanning analysis of the sample surface.The structure,material,size,precision and other aspects of the components of the device were fully studied in the process of device development.Through the debugging and improvement of three sets of devices,an integrated DBD solid sample microregion analysis device with advanced functions and easy operation was developed.2.The analytical performance evalution of the device was carried out,the characteristics of DBD micro-plasma were studied,and the feasibility of the device in quantitative analysis depth analysis and imaging analysis was explored.The emission spectra of He,Ar,and N₂ micro-plasma were measured by monochromator.He atomic spectrum lines and molecular ion spectrum lines mainly exist in He-micro-plasma emission spectra,in whichN₂⁺molecular ion spectrum lines are generated by penning ionization between high-energy He metastable atoms and impurity N₂ molecules.The production of N₂ and Ar micro-plasma is caused by filamentous discharge.Increasing discharge power could significantly increaseN₂⁺particle concentration in He-micro-plasma and increase the ablation efficiency of DBD micro-plasma.Both the discharge gas flow and the diameter of the DBD probe affected the shape of the DBD micro-plasma jet,and the sampling distance and sampling time were directly related to the morphology of the ablation spots.A direct quantitative analysis method for Cr,Hg and Pb on ABS plastic samples was estabished by DBD-ICP-MS.The R values of linear correlation of all three elements were greater than 0.99,the LOD was 252?g/g,24?g/g,167?g/g,respectively.The depth analysis of the metal coating on the printed circuit board gold finger was performed by DBD-ICP-MS.Moreover,the imaging analysis of Na Ca and I in mouse brain tissue sections was completed.The feasibility of the DBD solid sample microregion analysis device in the application of quantitative analysis,depth analysis and imaging analysis was confirmed,which laid a working foundation for the subsequent application research.3.The application of DBD-ICP-MS system to the image analysis of seal impression,ceramic lead glaze and stromatolite elements was studied.On the basis of parameter optimization,the study on ablation capability for different paper media by DBD micro-plasma was carried out,the position effect of ceramic lead glaze sample analysis was investigated,and the resolution of imaging analysis of stromatolite sample was explored.Finally,the Hg element imaging analysis of cinnabar mud imprint on seal carving,the Pb element imaging analysis of ceramic lead glaze samples and the Al,Si,K,Ca,Mn,Fe elements imaging analysis of stromatolites were realized by DBD-ICP-MS.In the study of the imaging analysis of ceramic lead glaze,it was found that the ablation spots of DBD micro-plasma were not obvious,while the ablation spots of LA were particularly obvious,indicating that the DBD micro-plasma had little damage to samples and was suitable for the analysis of painting and calligraphy cultural relics.In the imaging analysis of stromatolite,it was found the enrichment of elements such as Al,Si,K,Ca,Mn and Fe in the yellow rock layer,which was related to the formation of the yellow rock layer.The imaging resolution of the stromatolite samples by DBD-ICP-MS was less than 200?m.The DBD-ICP-MS analysis technology established in this paper can be tested and analyzed under atmospheric pressure.The simple operation and low energy consumption can greatly reduce the operation cost.This method will be a beneficial supplement to the existing solid microregion analysis technologies.At the same time,it is a fast and multi-element detection method.It is considered to be a supplement to the existing solid microanalysis technology.