中国激光, 2018, 45 (8): 0811001, 网络出版: 2018-08-11
基于偏振分辨LIBS技术的土壤重金属检测研究 下载: 834次
Detection of Heavy Metals in Soil Based on Polarization Resovled LIBS Technique
光谱学 土壤重金属 激光诱导击穿光谱 偏振 信背比 检测限 spectroscopy heavy metal of soil laser-induced breakdown spectroscopy polarization signal to background ratio limit of detection
摘要
为提高土壤重金属激光诱导击穿光谱(LIBS)特征谱线的信背比(SBR)和稳定性,并降低元素检测限,研究了土壤LIBS连续背景辐射以及Fe、Pb、Ca、Mg等4种元素特征分立谱线的偏振特性,对比分析了有、无偏振条件下元素特征谱线的相对标准偏差(RSD)、SBR与检测限。结果表明:4种元素的特征谱线Fe Ⅰ:404.581 nm、Pb Ⅰ:405.780 nm、Ca Ⅰ:422.670 nm和Mg Ⅰ:518.361 nm及其相应连续背景辐射的偏振度分别为0.27、0.17、0.25、0.23和0.70、0.64、0.69、0.67。偏振分辨LIBS(PRLIBS)技术使得4条特征谱线Fe Ⅰ:404.581 nm、Pb Ⅰ:405.780 nm、Ca Ⅰ:422.670 nm和Mg Ⅰ:518.361 nm的RSD分别降低了3.28%、2.2%、3.24%和1.34%。PRLIBS技术有效抑制了连续背景辐射,4种元素特征谱线的SBR分别提高了5.59、5.67、5.30、7.35倍。在有、无偏振条件下,Pb元素的检测限分别为17.4×10-6和39.4×10-6,偏振条件下的检测限为无偏振条件下的44%。以上研究结果为进一步提升土壤重金属的LIBS定量分析能力提供了数据支撑。
Abstract
In order to decrease the limit of detection of elements and improve signal-to-background ratio (SBR) and the stability of characteristic spectral lines of laser-induced breakdown spectroscopy (LIBS) of heavy metals in soil, we study the polarization property of four characteristic discrete spectral lines of Fe, Pb, Ca, Mg elements and continuous background radiation of LIBS in soil, and analyze the limit of detection, SBR and relative standard deviation (RSD) of characteristic spectral lines of elements under the conditions of polarization and no-polarization. The results indicate that the polarization degree of four characteristic spectral lines Fe Ⅰ: 404.581 nm, Pb Ⅰ: 405.780 nm, Ca Ⅰ: 422.670 nm, Mg Ⅰ: 518.361 nm and corresponding continuous background radiation are 0.27, 0.17, 0.25, 0.23 and 0.70, 0.64, 0.69, 0.67, respectively. The polarization resolved LIBS (PRLIBS) technology makes RSD of four characteristic spectral lines Fe Ⅰ: 404.581 nm, Pb Ⅰ: 405.780 nm, Ca Ⅰ: 422.670 nm, Mg Ⅰ: 518.361 nm decrease by 3.28%, 2.2%, 3.24% and 1.34%, respectively. Continuous background radiation is effectively depressed by PRLIBS technology, and SBR of four characteristic spectral lines is increased by 5.59, 5.67, 5.30, 7.35 times, respectively. Under the conditions of polarization and no-polarization, the limits of detection of heavy metal Pb are 17.4×10-6 and 39.4×10-6, respectively, limit of detection under polarization is 44% that of non-polarization. Above results provide data support for further improving quantitative analysis ability of LIBS on heavy metal in soil.
余洋, 赵南京, 孟德硕, 马明俊, 兰智高. 基于偏振分辨LIBS技术的土壤重金属检测研究[J]. 中国激光, 2018, 45(8): 0811001. Yu Yang, Zhao Nanjing, Meng Deshuo, Ma Mingjun, Lan Zhigao. Detection of Heavy Metals in Soil Based on Polarization Resovled LIBS Technique[J]. Chinese Journal of Lasers, 2018, 45(8): 0811001.