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研究了激光诱导击穿光谱(LIBS)对农产品中低浓度重金属元素的探测能力。土豆样品经过实验室污染处理,获得鲜样Pb元素含量范围在9.0~30.0 mg/kg的污染样品。再对样品进行烘干、粉碎、压片处理,以消除水分和样品基体效应对LIBS检测效果的影响。利用微波辅助LIBS(MA-LIBS)的方法对样品和激光烧蚀产生的等离子体进行加热,探讨了MA-LIBS对目标元素Pb的信号强度增强效果。实验结果显示,MA-LIBS能显著提高元素谱线的探测能力,对于Pb I 405.78 nm特征谱线,最低浓度的含Pb土豆样品谱线强度能提高6倍以上,其余样品也有类似的规律。说明M A-LIBS在提高目标元素探测能力上有巨大的发展潜力。
The laser-induced breakdown spectroscopy (LIBS) was used to detect low concentrations of heavy metals in agricultural products. Potato samples were subjected to laboratory pollution treatment to obtain fresh samples with contaminated Pb ranging from 9.0 to 30.0 mg / kg. Then the samples were dried, crushed, tabletting treatment to eliminate the effects of water and matrix effects on the detection of LIBS. The MA-LIBS (MA-LIBS) method was used to heat the plasma generated by the sample and laser ablation, and the signal enhancement effect of MA-LIBS on the target element Pb was discussed. The experimental results show that MA-LIBS can significantly improve the detection ability of elemental spectra. For the Pb I 405.78 nm characteristic line, the lowest concentration of lead-containing potatoes can increase the spectral line intensity by more than 6 times and the other samples have similar rules. This shows that M A-LIBS has great potential for improving the detection of target elements.