双光束激光诱导击穿光谱提高污染大米中镉元素检测灵敏度实验

Improvement of Analytical Sensitivity on Detecting Cd Residue in Rice by Dual Pulse Laser Induced Breakdown Spectroscopy

食品重金属污染日趋严重,为了探索激光诱导击穿光谱(LIBS)在农产品质量安全检测领域的应用价值,以实验室污染处理的含镉(Cd)大米为例,采用共轴双脉冲激光诱导击穿光谱(DP-LIBS)装置并对实验中的关键条件参数进行优化,探讨了DP-LIBS在提高农产品重金属检测灵敏度与准确度方面的可行性。采用LIBS技术和阳极溶出伏安法,获取9个浓度梯度的含Cd大米样品的LIBS光谱及Cd元素真实浓度信息,再采用一元线性定标回归模型,对Cd的三个特征光谱进行定量分析。结果表明,DP-LIBS能够检测到实验大米样品中Cd元素的最低质量比为5.03μg/g,Cd元素特征谱线强度与其浓度拟合直线均具有较高的线性相关性。研究表明,DP-LIBS能够提高Cd元素的检测灵敏度与准确度,并可通过一元线性回归模型得到Cd的浓度信息。

Heavy metal pollution is more and more serious in agriculture products. In the experiment, the rice polluted by cadmium is used as an example. We adopt coaxial dual pulse laser induced breakdown spectroscopy and the experimental parameters are optimized. The application of dual pulse-laser induced breakdown spectroscopy （DP-LIBS） in the area of monitoring the quality and safety of the farm products are explored. The feasibility of improving the sensitivity and accuracy for detecting the heavy metal in agricultural products is disscussed. The intensity of LIBS spectra and the real concentration of Cd of the nine concentration gradients samples are obtained by LIBS and anodic stripping voltammetry. By using univariate linear scaling regression model, three characteristic spectrum of Cd is analyzed quantitatively. The results indicate that the lowest mass fraction of Cd is detected by DP- LIBS with 5.03μg/g and all the spectra lines have good correlation coefficients. The experiment shows that DP- LIBS can improve the detecting sensitivity and accuracy of Cd, its concentration information of Cd is got according to the linear regression model.