为了提高激光诱导击穿光谱(LIBS)技术检测水溶液的灵敏度和重复性，利用激光诱导击穿光谱对水溶液中Pb元素进行检测分析。采用滤纸作为固体基质，选取Mn作为Pb的内标元素，将配置好的不同浓度的Pb溶液滴入滤纸中，比较采用内标法与无内标法定标的分析结果，表明选取Mn作为Pb的内标元素的定标曲线拟合相关系数R2达到0.998,检测限与实际测量值的相对误差较小。通过对实验系统的探测延时、门宽等参数的优化，在更低的激发能量下，经线性拟合计算得到Pb元素的检测限为3.87 mg/L质量浓度，与以往实验中利用喷流方式检测相比，检测灵敏度提高了大约10倍，而且与同类方法比较检测限也相对较低。该实验系统样品处理简单，节省检测时间，为LIBS应用到现场快速检测重金属元素提供了一种较为实际的方法。

In order to improve detection sensitivity and reproducibility of metal element analysis in aqueous solutions using laser induced breakdown spectroscopy (LIBS), a paper slice has been used as a liquid absorber to transform liquid sample analysis to solid sample analysis. Calibration curves for metal element Pb under different concentrations have been obtained. The results demonstrate that the analysis accuracy and error of detection limit produced by the internal standard method are more precise than those in absence of internal standard. Mn is chosen as the reference element. With optimized experimental parameters, such as the delay time for LIBS signal detection, gate width and pulse energy, the detection limit of Pb is determined to be 3.87 mg/L, which is lower than those obtained by similar detected methods. The detection sensitivity is about ten times higher than that in our previous experiments, in which the laser pulse is focused on the surface of the liquid jet. The paper sample is very easy to handle so that the detected time can be greatly shortened. As the lower pulse energy is needed, this approach provides a more practical approach for metal element analysis in aqueous solutions by using LIBS.