等离子体光栅诱导击穿光谱检测土壤重金属元素  

Plasma Grating Induced Breakdown Spectroscopic Detection of Heavy Metal Elements in Soil

作　　者：施沈城 胡梦云[1,2,3] 张青山 曾和平 Shi Shencheng;Hu Mengyun;Zhang Qingshan;Zeng Heping(State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai,200062,China;Chongqing Key Laboratory of Precision Optics,Chongqing Institute,East China Normal University,Chongqing,401120,China;Shanghai Key Laboratory of Modern Optical System,School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai,200093,China)

机构地区：[1]华东师范大学精密光谱科学与技术国家重点实验室,上海200062 [2]华东师范大学重庆研究院精密光学重庆市重点实验室,重庆401120 [3]上海理工大学光电信息与计算机工程学院上海市现代光学系统重点实验室,上海200093

出　　处：《中国激光》2022年第13期145-151,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金重点项目(62035005);国家自然科学基金仪器项目(11727812)。

摘　　要：搭建了等离子体光栅诱导击穿光谱(plasma-grating-induced breakdown spectroscopy,GIBS)系统对土壤样品进行分析,并与光丝诱导击穿光谱(filament-induced breakdown spectroscopy,FIBS)系统进行对比,成功得到2倍左右的谱线信号增强,该谱线信号增强与脉冲间的延时密切相关。此外,通过研究不同激光能量下样品空间位置改变对谱线信号的影响,证明了GIBS系统样品最优激发位置范围虽然相比于FIBS系统有所减小,但是其不会像FIBS系统一样随激光能量的改变而改变。对土壤中重金属元素Cr进行了定量研究,发现FIBS与GIBS系统都能够建立线性的定标曲线,其中FIBS系统的检出限为55.09×10^(-6),而GIBS系统的检出限为29.96×10^(-6),表明GIBS技术具有更高的探测灵敏度。Objective Laser-induced breakdown spectroscopy(LIBS)is a novel atomic-emission spectroscopic technique,which has many advantages such as multi-elemental detection,rapid response for online monitoring,and easy sample preparation for in situ measurements,and it has been applied in many fields.However,nanosecond laser-induced breakdown spectroscopy(ns-LIBS)still has some defects such as poor stability,low analysis accuracy,and matrix effects.Many methods have been proposed to solve these problems.Among them,filament-induced breakdown spectroscopy(FIBS)and plasma-grating-induced breakdown spectroscopy(GIBS)based on femtosecond laser excitation do not require the introduction of additional equipment and sample preparation steps if compared with other methods.In FIBS,a long and stable filament is used to ablate samples.And it has been proved that FIBS has very stable analysis results and can be used to realize remote sensing detection.And GIBS is based on the plasma grating formed by the interaction of two non-collinear filaments to excite samples.A significant increase in spectral line intensity has been successfully observed in the comparative experiment between FIBS and GIBS.However,the length of the plasma grating is greatly reduced compared with that of the filament,so it is necessary to investigate the analysis stability of the GIBS technology.In addition,the influence of the enhanced spectral line intensity brought by the GIBS technology on the detection limit is still to be studied.Methods We build a GIBS system based on a plasma grating formed by the interaction of two filaments intersecting at a small angle to ablate the sample and generate plasma.In order to better control the experimental variables,we realize the conversion to the FIBS system by blocking one of the light filaments in the GIBS system.The sample is placed on a three-dimensional translation table to avoid over-ablation and the position of the sample relative to the focal point of the lens is changed.We collect the light emission from the induc

关 键 词：光谱学 激光诱导击穿光谱技术 光丝 等离子体光栅 检出限 重金属 

分 类 号：O433.4[机械工程—光学工程]