蔬菜叶片重金属的LIBS定量化快速测量机理与模型研究

项目名称： 蔬菜叶片重金属的LIBS定量化快速测量机理与模型研究

项目编号： No.31271614

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 农业科学

项目作者： 董大明

作者单位： 北京市农林科学院

项目金额： 76万元

中文摘要： 随着工农业的发展和环境污染的加剧，重金属污染已成为制约蔬菜业发展的重要瓶颈并危害着人类的健康。传统的蔬菜重金属检测方法周期长、成本高、具有破坏性，不能实现快速检测。本项目瞄准这一科学难题，以LIBS（Laser Induced Breakdown Spectroscopy）技术为手段，以未经处理的新鲜叶片为测量对象，开展蔬菜中典型重金属的定量化测量机理和模型研究，为研制便携式蔬菜重金属检测仪器奠定理论基础。项目从激光击穿叶片的物理机制入手，通过自由电子密度和激光等离子体温度分析，建立描述击穿过程的局部热平衡模型；研究蔬菜重金属的LIBS光谱峰位、时间演化规律等特征，并明确实验参数对LIBS谱线的影响规律；分析测量中的噪声源和噪声特性，研究LIBS谱线的预处理方法以提高预测精度；通过物理机制和特性规律的分析，建立蔬菜重金属的内定标、外定标曲线和自由定标方法，并研究多元变量回归模型。

中文关键词： 蔬菜；重金属；激光诱导击穿光谱；定量化；

英文摘要： With the development of industry and agriculture and the aggravation of environmental pollution, heavy metal contamination in vegetables has become a bottleneck for the development of vegetable industry and a big threat to human health. Traditional methods for measurement of heavy metals in vegetables are time-consuming, expensive and destructive, and unable to realize fast measurement. The purpose of this project is to solve the worldwide difficult problem of in situ fast detection of heavy metals in fresh vegetables. In this study, LIBS (Laser Induced Breakdown Spectroscopy) technique is used to measure typical heavy metals in unprocessed, fresh vegetables. The mechanism and modeling methods would be studied, to lay a theoretical foundation for the development of portable instrument. The project studied the physical mechanism of laser ablation on vegetables at first. The local thermal equilibrium model that describes the ablation progress will be established, through analyzing the density of free electrons and the temperature of laser plasma. The LIBS spectral characteristics of heavy metals in vegetables, such as spectral peak positions, time evolution characteristics would be studied, and the effects of experimental parameters on spectral characteristics would be analyzed. Through analyzing the major noise s

英文关键词： Vegetables；heavy metal；Laser Induced Breakdown Spectroscopy；Quantification；