激光诱导击穿光谱烟叶Cu谱线等离子体参数及定量分析

农业领域中对植株元素的快速检测和实时监控十分重要。采用Nd∶YAG激光器和中阶梯ICCD光栅光谱仪获取金属元素Cu等离子体谱线。为研究激光诱导击穿光谱(laser induced break-down spectroscopy，LIBS)金属元素Cu定量分析的标定曲线和等离子体参数，制备Cu含量范围为8.59～156.35 μg·g-1烟叶样品进行实验。实验结果表明烟叶中金属元素Cu特征谱线324.75 nm处干扰小、谱线明显。烟叶样品受激发产生等离子体温度为39 458.94 K，Cu等离子体电子密度为0.74×1016，谱线强度和样品浓度建立的标定曲线相关系数r为0.98，平均相对标准偏差RSD(relative standard deviation)为2.59%，Cu含量理论最低检测限为7.72 μg·g-1，谱线信噪比(SNR)为7.86。激光诱导击穿光谱方法可以应用于卷烟生产线在线检测金属元素Cu含量和监测烟叶中金属元素Cu对烟草生长的影响。

Study on Quantitative Analysis and Spectroscopy Characteristics of Cu in Tobacco by Laser Induced Breakdown Spectroscopy

The rapid detection and real-time monitoring of plant elements is very important in the field of agriculture.A method using Laser Induced Breakdown Spectroscopy (LIBS)for the determination of the spectroscopy characteristics of Cu in tobacco was evaluated.To perform the calibration curve,several tobacco samples containing Cu arranged from 8.59 to 156.35 μg·g-1 were prepared.The amount of Cu prepared in laboratory was measured using atomic absorption spectroscopy.Experiments indi-cated that the characteristic spectrum of Cu at the wavelength of 324.75 nm was quite clear,and easy to obtain.From the char-acteristic spectra obtained from Cu-contained samples,the temperature and density of the plasma induced by laser were calculated to be 39458.94 K and 0.74×1016 ,respectively.The fitting curve between the intensity of the spectral lines and the sample con-centrations was established with the correlation coefficient (r square)of 0.98 ,the mean relative standard deviation (RSD)of 2.59%,the limit of detection (LOD)of 7.72 μg·g-1 and the spectral signal-noise ratio of 7.86.The method was successfully applied to predict the Cu amounts in tobacco samples,which has a potential to be used in cigarette production lines and tobacco breeding.