| X-ray fluorescence spectrometer is suitable for material composition analysis. It can simultaneously analyze multielement of major and trace elements both in solid samples(block or powder) and liquid samples. When combined with thin sample technology, it has the advantages of high sensitivity and little sample and so on. With the development of analysis technology and the improvement of scientific research, the field of analysis research has the characteristics of the complicated composition and low contents of the component under test, which puts higher requirements to the instrument itself. The group of teachers guided by the Professor Tian Yuhong develops a new type instrument of XRF with high sensitivity, which improved the research of apparatus based on the total reflection X-ray fluorescence analyzer. The thesis mainly introduces the instrumentalstructure andwe mainlyapply theinstrumenttotraceelementsanalysis.This thesis mainly includesfourparts:Part one: This thesis introduces the principle of X-ray fluorescence, development history and application of X-ray fluorescence spectrometer, the principle and application of common sample pretreatment methods and combination methods. Meanwhile, it illustrates the thoughts of setting up thetopics andmain researchcontents ofthis thesis.Part two: The thesis introduces the structural device and quantitative analysis methods of the new type instrument of XRF developed by our group, meanwhile, do experimental work of the instrument performance. The new type XRF analyzer mainly includes the excitation system, detector system, recording unit, high voltage generator and vacuum pump parts and so on. Using Mo and Ti two targets of X-ray tube excitation system, it is combined by silicon drift detector of X-123 type and DPP digital pulse processor. Its quantitative analysis technology is implemented by the thin sample and internal standard method. Through the sensitivity calibration curve, K line deviation of each element is less than ±1% of each element. L line deviation of each element is less than ±1 %.Precision(RSD) is between 2.2 %~5.8 %(n=6). Method detection limit and the quantitative limit of eachelementarerelatively good.Part three:The thesis is applying to analyze the inorganic elements in pine needles and its pollen of Cedrus deodara by the new type instrument of XRF, and systemically studies the situation of several inorganic elements changing in the pine needles of Cedrus deodara around one year growthprogress. The results shows that the pine needles and its pollen of Cedrus deodara have several required inorganic elements of plants on its growth progress, such as K, Ca, Ti, Mn, Fe, Co, Cu, Zn,Rb, Sr and so on, among them, the content of K, Ca is on the top, the content of Mn, Fe takes the second place. The same element in low, medium and high three kinds of different standard addition level shows the average standard addition between 94 %~104 %, which can meet the requirement on the determination of trace. The results of determination of practical samples by XRF method and ICP-AES method show basic coincidence. In annual growth cycle, the content of each inorganic elements in pine needles of Cedrus deodara on three locations is different, but the overall appear certain regularity. The content of each inorganic elements in old pine needles of Cedrus deodara does nothave upheavalin differentmonthandthecontents arestable.Part four: Applying the coupling technique of combinating the electrochemistry and the new type instrument of XRF to basic research of sedimentary copper ions. Experimentally study the deposition of copper ions p H, deposition potential, deposition time, the influence of different salinity of electroplating copper, different work area of glassy carbon electrode of electroplating copper, the influence of multiple ion coexist of electroplating copper and copper deposition rate of different concentrations of copper standard solution. At the same time, makes the actual recovery experiment of practical samples. The results show that the best acetic-acid sodium acetate buffer system of precipitating copper ions is p H = 5. The best deposition potential of copper ions is-0.6 V. The increase of salinity can increase ionic strength of solution which make the deposition rate of copper ions is improved, but it is not the main factor for affecting the copper ion deposition. The deposition rate of copper ion shows positive correlation with the deposition time and glassy carbon electrode area. The coexistence of multiple ions does not affect the deposition of copper ions. Comparing the test of XRF with ICP-AES, the test results are consistent. The deposition rate of different concentrations of copper standard solution is relatively close, which is between 1.26 %~2.06 %.The coupling technique of combination the electrochemistry and the new type instrument of XRF are applied to test the practical samples, and the date of standard addition recovery experiment is conformity with the detection data of standard copperions. |
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