摘要
为了降低或消除激光诱导击穿光谱(LIBS)检测过程中激光能量、背景辐射、噪声信号对特征光谱信息的影响,以镉靶材为对象,构建偏振分辨激光诱导击穿光谱(PRLIBS)系统,探索提高重金属污染物LIBS分析能力的方法。结合光波在多层媒介传播过程中的菲涅耳方程,分析入射光波长对光强透射比的作用机理,构建正入射方向上的等离子体辐射强度分光透射比模型。利用该模型获得了相同条件下的LIBS、PRLIBS光谱数据,比较了镉元素特征谱线强度的相对标准偏差(RSD),并分析了不同延迟时间下特征谱线强度的变化趋势。结果表明:在低能量密度情况下,PRLIBS具有明显的测量优势,可以采集到更多的特征峰信号,并且PRLIBS光谱特征谱线强度的RSD值小于相同检测参数下LIBS光谱特征谱线强度的RSD值,说明分光透射比模型能够有效提高等离子体光谱的稳定性;LIBS与PRLIBS的谱线强度随延迟时间的变化趋势一致,说明PRLIBS并不影响原有LIBS的延迟时间;随着脉冲能量增大,分光透射比模型可以有效降低基线漂移和背景辐射,增强光谱的分辨能力;分光透射比模型不仅保留了连续谱中的有效信息,还提高了谱线识别的稳定性,对于提高低激光能量诱导条件下LIBS特征谱线识别能力具有重要的参考意义。
Objective Heavy metal pollution poses a threat to the ecological environment,economic development,and human health.As a heavy metal pollutant,cadmium(Cd)is difficult to be decomposed by microorganisms,and its excessive intake can lead to cancerous lesions in the kidneys and other organs.Presently,the routine detection methods of Cd element,such as ICP-MS,ICP-OES,and AAS,require the use of chemical reagents to digest the samples,and the detection process is environmentally unfriendly and tedious.Laser-induced breakdown spectroscopy(LIBS)is a typical elemental analysis method with the advantages of a high analysis speed,multi-element measurement,and real-time detection.This has been widely studied in many fields.However,owing to the existence of the matrix effects in the samples,the collected spectral data have high bases and large background noise,and the self-absorption phenomenon is highly severe.Therefore,the stability,accuracy,and sensitivity of the analysis results must be improved.To reduce or eliminate these problems during the LIBS detection process,we constructed a polarization-resolved LIBS(PRLIBS)system to explore methods to improve the analytical ability of LIBS.Stability is promoted,and the baseline drift and background radiation are reduced using PRLIBS.We hope that our study provides a reference for the improvement of the analytical ability of LIBS.Methods A Cd target was selected as the object in the present study.Combined with the Fresnel equation of light wave propagation in multilayer media,the mechanism of the effect of the incident light wavelength on the light intensity transmittance is analyzed.A light-splitting transmittance model of the plasma radiation intensity in the normal incident direction was established.MATLAB software was used to simulate the model and analyze the changes in the transmitted light intensity.A Cd target was used for the actual measurement verification.The spectral data of the LIBS and PRLIBS with different laser energies and delay time were obtained,and their effect
作者
曾敏
王晓
万奇
谢玮萍
姚明印
黄林
王建波
姚小英
徐将
Zeng Min;Wang Xiao;Wan Qi;Xie Weiping;Yao Mingyin;Huang Lin;Wang Jianbo;Yao Xiaoying;Xu Jiang(School of Engineering,Jiangxi Agricultural University,Nanchang 330045,Jiangxi,China;Key Laboratory of Optics-Electrics Application of Biomaterials of Jiangxi Agricultural University,Nanchang 330045,Jiangxi,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第19期208-216,共9页
Chinese Journal of Lasers
基金
国家自然科学基金(32260626,32260632)
江西省教育厅科学基金(GJJ210421,GJJ210437)。
关键词
光谱学
偏振分辨激光诱导击穿光谱
分光透射比
Glan-Thompson棱镜
镉
识别能力
spectroscopy
polarization-resolved laser-induced breakdown spectroscopy
light-splitting transmittance
Glan-Thompson polarizer
cadmium
recognition ability
