【作者】 徐媛；

【导师】 严霖元； 姚明印；

【作者基本信息】 江西农业大学 ， 农业电气化与自动化， 2013， 硕士

【摘要】 目前，水体重金属污染越来越严重，传统的检测方法速度慢、预处理复杂，难以满足现代社会的需求。因此，如何对水体重金属进行快速有效的检测成为国内外研究的热点。本文研究采用激光诱导击穿光谱技术(LIBS)对水体重金属进行快速原位检测的新方法。论文的总体思路如下：首先，从选题的背景开始论述，介绍了液相基质中元素检测的研究现状，LIBS技术的研究进展。其次，详细介绍了激光诱导击穿光谱的理论基础，搭建了LIBS实验装置系统并根据溶液检测的特殊性进行了优化；分别配置了重铬酸钾溶液和硝酸铅溶液，以铬元素（Cr）和铅元素（Pb）为研究对象，通过LIBS实验确定了重金属元素铬的最优观测谱线为425.44nm，铅的分析谱线为405.78nm。再次，对Cr和Pb的LIBS信号进行了定性分析。在实验过程中延时时间、激光能量大小、重复频率和激光脉冲累积次数对激光等离子体信号具有一定的影响机制，通过研究这些参数对元素LIBS信号强度的影响，确定了在本实验中对铬元素进行检测的最佳延时时间为1280ns，最优激光能量大小值为120mJ，最佳激光累积次数为15次，最优重复频率为1Hz；对铅元素进行检测的最优延时为3000ns，最优激光能量大小值为70mJ，最佳激光累积次数为30次，最优重复频率为2Hz。然后，在实验的最佳参数下，分别采用强度直接定标法、内标法及偏最小二乘法对铬元素和铅元素进行了定量分析。验证了激光诱导击穿光谱技术快速分析水体重金属的能力。最后，论文对实验进行了总结，并对LIBS技术应用于溶液中重金属元素的检测进行了展望。更多还原

【Abstract】 At present, the water heavy metal pollution is more and more serious. The traditionaldetection methods are slow, pretreatment and complex, they are difficult to meet the needsof modern society. Therefore, how to detect aqueous heavy metals quickly and efficientlyis becoming a hotspot research at home and abroad. In this paper, a new method has beenstudied to detect the heavy metals fast and in situ by laser induced breakdown spectroscopy(LIBS). Main research works are as follows:Firstly, the thesis begins with a brief background introduction of this work. Theresearch of the liquid matrix element detection and the research progress of LIBStechnology were introduced.Secondly, the LIBS experimental setup was built and optimized according to theparticularity of the solution detection. Potassium dichromate solution and lead nitratesolution were configured. As the research object, trace heavy metal element Cr and Pbwere measured by LIBS. The optimal observation line was established in this experiment,PbⅠ405.78nm and CrⅠ425.43nm were chosen to be the analytical lines.Again, the characteristics of the laser induced plasma in water have been investigatedwith potassium dichromate solution and lead nitrate solution samples in this work. Thetemporal evolution property、the cumulative frequency、the different repetition frequencyand the influence of the pulse laser energies on the LIBS signal of Cr and Pb element areinvestigated respectively. The experimental results showed that the best delay time is1280ns and3000ns and the optimal laser energy is120mJ and70mJ and the best cumulativefrequency is15times30times and the optimal repetition frequency is1Hz and2Hz forthe solution of K2Cr2O7and Pb(NO3)2respectively in this experiment.Then, under the best parameters of the experiment, the strength of the directcalibration method, internal standard method and partial least squares method are takeninto the calibration of Cr and Pb element in sample. It indicated that laser-inducedbreakdown spectroscopy is suitable for rapidly component quantitative analysis in solutionwith receptible applicability.Finally, the research conclusions were summarized, and some suggestions on thefurther work and hope were presented.更多还原