应用激光诱导击穿光谱测量水体中痕量重金属锌

利用激光诱导击穿光谱(LIBS)对水体中痕量重金属锌进行定性及定量分析,以1064nm波长Nd…YAG脉冲激光为激发光源,采用高分辨率、宽光谱段的中阶梯光栅光谱仪和增强型电荷耦合器件(ICCD)为谱线分离与探测器件,以锌(Zn:481.1nm)特征谱线作为分析线,测定不同浓度下的特征谱线强度。实验中以固体圆饼状石墨块为样品基体进行元素富集,滴定固定量的已知不同浓度的氯化锌溶液于基体表面固定区域,烘干并制备实验待测样品。结果表明,锌的最佳探测延迟时间为1100ns,元素谱线强度随着样品浓度的增加而增大并在较低浓度下呈线性关系,得到水体中锌元素的痕量检测限4.108mg/L。研究结果为进一步开展水体痕量重金属的激光诱导击穿光谱测量提供了方法。

Measurement of Trace Heavy Metal Zinc in Water by Laser Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy is used in qualitative and quantitative analysis of trace amounts of heavy metals zinc in water,with 1064 nm Nd…YAG laser as the excitation light source and high resolution,wide spectral range echelle spectrometer and intensified charge-coupled device(ICCD) as the line separating and detecting devices.The characteristic line at 481.1 nm is chosen as the analysis line to measure the characteristic line intensities of different zinc concentrations.A solid state graphite round flat is used as matrix for element enrichment to reduce water splashing,extend the plasma lifetime and improve the detection sensitivity.The experimental sample is prepared by titrating a fixed volume of zinc chloride solution of different concentrations on a fixed area of the graphite matrix.The results show that the optimal detection delay time is about 1100 ns.The spectrum intensity rises with the concentration increasing,and a good linear relationship is found at low concentration region.The lower limit of detection of zinc in water of 4.108 mg/L is obtained.A measurement method for further study of trace heavy metals in water is provided with laser induced breakdown spectroscopy technique.