激光诱导击穿光谱土壤和玉米中金属元素快速测定技术探索研究

发布时间：2018-05-20 22:09

本文选题：激光诱导击穿光谱 + 等离子体　；参考：《河南农业大学》2016年硕士论文

【摘要】：目前,在土壤和玉米金属元素检测方面,还不能实现对样本的在线识别和定量分析。研究者仍然依赖电感耦合等离子体原子吸收光谱等传统光谱方法对样本中的金属元素进行检测,这种检测方法周期长,操作过于复杂,因此探索一种能够实时在线检测土壤和玉米金属元素的方法便具有重大的现实意义。论文在分析研究针对土壤和玉米金属元素检测传统技术的基础上,试图探索激光诱导击穿光谱(Laser induced breakdown spectroscopy,LIBS)土壤和玉米金属元素Cu、Mn快速定量的检测方法。激光诱导击穿光谱,是一种等离子体激发射光谱,因其操作简便、检测速度快和分析能力强得到广泛应用,在环境监测、农业和生命科学等方面具有重大意义。但由于该方法本身的原理以及仪器自身分辨率的限制,在实际应用过程中遇到很多困难,包括噪声来源多、分析精度低和重复性差等。本论文研究了激光诱导产生等离子体特性、等离子体发射光谱原理,并构建以及改进LIBS实验平台;研究了LIBS实验平台的光学系统结构,通过对影响LIBS性能的参数进行优化,改进LIBS光学系统光路结构和激光脉冲的触发信号控制方式;分析了LIBS检测土壤和玉米中的Cu、Mn金属元素的实验数据,实验中检测了不同浓度的土壤和玉米中Cu、Mn金属元素的发射特征谱线,获得了Cu、Mn金属元素的LIBS相对最佳光谱,在获得的光谱数据基础上使用了极小值筛选法扣除LIBS光谱中的连续背景光谱。论文通过建立标定曲线对玉米Cu、Mn元素的含量进行定性和定量分析,实验结果显示土壤中Cu的检测限13.61μg.g-1,玉米中Cu、Mn检出限为12.39μg.g-1和14.35μg.g-1,表明激光诱导击穿光谱技术能够快速检测土壤和玉米中的金属元素,为金属元素的快速定量检测及分析提供了新的途径。
[Abstract]:At present, the on-line identification and quantitative analysis of samples can not be realized in the detection of soil and corn metal elements. The researchers still rely on the traditional spectral methods such as inductively coupled plasma atomic absorption spectrometry to detect metal elements in the samples. This method has a long period and too complex operation. Therefore, a kind of energy is explored. The method of real-time on-line detection of soil and corn metal elements is of great practical significance. On the basis of analyzing the traditional techniques for soil and maize metal elements detection, the paper tries to explore the rapid quantitative analysis of laser induced breakdown spectroscopy (Laser induced breakdown spectroscopy, LIBS) soil and corn metal element Cu, Mn The laser induced breakdown spectroscopy (laser-induced breakdown spectroscopy) is a plasma stimulated emission spectrum. It is of great significance in environmental monitoring, agriculture and life science because of its simple operation, rapid detection speed and strong analytical ability. But because of the principle of the method itself and the limitation of the resolution of the instrument itself, it has been applied in practice. There are many difficulties in the process, including many sources of noise, low accuracy and poor repeatability. This paper studies the characteristics of plasma induced plasma, the principle of plasma emission spectrum, and the construction and improvement of the LIBS experimental platform. The structure of the optical system of the LIBS experimental platform is studied, and the parameters that affect the performance of the LIBS are optimized. The light path structure of LIBS optical system and the trigger signal control mode of laser pulse were improved. The experimental data of LIBS detection of Cu and Mn metal elements in soil and maize were analyzed. The emission characteristic lines of Cu and Mn metals in soil and maize with different concentrations were detected in the experiment, and the LIBS relative optimum spectrum of Cu and Mn metal elements was obtained. On the basis of the obtained spectral data, the minimum value screening method was used to deduct the continuous background spectrum in the LIBS spectrum. By setting up the calibration curve, the content of Cu and Mn elements in maize was analyzed qualitatively and quantitatively. The experimental results showed that the detection limit of Cu in the soil was 13.61 Mu g.g-1, the Cu in maize, Mn detection limit was 12.39 mu g.g-1 and 14.35 micron g.g-1, indicating the excitation. Photoinduced breakdown spectroscopy can quickly detect metal elements in soil and corn, and provide a new way for rapid quantitative detection and analysis of metal elements.
【学位授予单位】：河南农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S513;S153

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