【摘要】 以1 064nm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ICCD为谱线分离与探测器件,实验研究了水体中痕量镍元素的激光诱导等离子体光谱发射特性和检测限;为了延长水体中金属元素的激光等离子体光谱发射时间、提高光谱检测灵敏度并减小ns激光作用下水滴溅射的影响,实验中以固体圆饼状石墨块为样品基体进行元素富集,通过在基体表面固定区域滴定固定量的已知不同浓度的硝酸镍溶液,烘干并制备待测样品。研究表明,镍的最佳探测延迟时间在700ns左右,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现良好的线性关系,计算得到水体中Ni元素的痕量检测限为0.28,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。更多还原

【Abstract】 The spectroscopy emission characteristics and th e detection limit of trace heavy metal nickel in water was studied based on lase r induced breakdown spectroscopy technique,with a 1 064 nm wavelength Nd∶YAG l a ser as excitation source,and the echelle spectrometer and ICCD detector were us ed for spectral separation and high sensitive detection with high resolution and wide spectral range.A round flat solid state graphite as matrix was used for e lement enrichment for reducing water splashing,extending the plasma lifetime an d improving the detection sensitivity,and the experimental sample was prepared by titrating a fixed volume of nickel nitrate solution of different concentratio ns on a fixed area of the graphite matrix.The results show that the better dete ction delay time is about 700 ns,the spectrum intensity raises with the concent ration increase,a good linear relationship is presented at low concentration wi th a correlation coefficient 0.996 1,and the lower limit of detection of nicke l in water with 0.28 mg·L-1 was retrieved.A measurement method for furthe r study o f trace heavy metals in water is provided with laser induced breakdown spectrosc opy technique.更多还原