第十五届全国原子与分子物理学术会议: 用激光诱导击穿光谱技术定量分析油漆中的有害重金属

很多轻工业产品需要用到油性油漆，其中的重金属元素的含量是否超标将会直接影响到产品质量及其安全性。因此发展轻工产品中重金属含量的快速检测技术，对促进国民经济的发展和保障消费者生命安全具有重要的意义。我们利用激光诱导击穿光谱技术实现了对油漆中有害重金属含量的快速定性和定量分析。通过观测激光等离子体中重金属原子辐射强度可以定性测量重金属含量的大体水平。然后，在相同检测条件下，将已知浓度的标准样品作为参考，制定出各元素的校正曲线，使用外标法，就能够实现定量分析。对Pb、Cr、Cd三种有害重金属元素，目前检出限分别达到9、3.5和23ppm的水平，分析相对误差小于10%，单次测量时间短于2分钟。汞的结果不太理想，检测灵敏度相对偏低，与其原子辐射寿命较短有关。我们将采取脉冲放电延长汞原子辐射弛豫时间的措施来改进汞元素的分析灵敏度，使其达到较高水平。

Quantitative analysis of toxic heavy metal in paints with laser-induced breakdown spectroscopy

Oil paints are used on many light industrial products. The concentration of heavy metals in paints is one of critical standards for quality control of the products and their safeties for use. To develop a rapid and quantitative analysis technique for detection of heavy metals in light industrial products is very important for economy development and ensuring their safeties for use. A rapid, both qualitative and quantitative analysis method of toxic heavy metals in paints with laser-induced breakdown spectroscopy (LIBS) was developed. By observing atomic emission intensities from paints samples, the concentrations of heavy metals can be qualitatively estimated. A quantitative analysis can be realized by using external standard method, while the calibration curves are determined using a few reference samples in which the concentrations of heavy metals are known and are measured under the same experimental conditions. The limits of detection of Pb, Cr and Cd were determined to be 9, 3.5 and 23ppm, respectively. Relative measure error is less than 10% and the time required for single measurement is 2 minutes. The results of mercury are not good at the moment. Its detection sensitivity is relatively poor due to its short lifetime of the upper state corresponding to the analysis line. It is planed to enhance the detection sensitivity of mercury in our laboratory by using pulsed discharge to extend the decay time of mercury atomic emission.