脐橙含铅量的激光诱导击穿光谱检测实验研究

Analysis of the Pb Element in Gan Nannavel Orange Based on Laser-Induced Breakdown Spectroscopy

实验利用1064nm Nd:YAG纳秒激光器诱导击穿脐橙样品产生等离子体光谱,用八通道光纤光谱仪测量脐橙的激光诱导击穿光谱(LIBS)特性,通过鉴别分析,选取铅的(PbI 405.78nm)特征谱线作为分析线,测定不同铅浓度下的特征谱线强度,根据谱线强度与浓度的关系,建立定标曲线。实验结果表明,脐橙中重金属铅元素含量较低时,其光谱谱线强度与浓度呈线性关系,其拟合度为0.95;脐橙中重金属铅元素含量较高时,等离子体发射光谱的谱线存在自吸收现象,使其定标曲线向下偏移趋势,呈现曲线关系,其拟合度为0.98。LIBS技术还可以快速分析出水果样品中重金属元素的相对含量,能实际应用于与食品安全相关的领域。

In the experiments, laser induced breakdown spectra produced by infrared radiation of Nd： YAG nanosecond laser, are measured by fiber optic spectrometer for navel orange. The characteristic spectral line of PbI 405.78 nm is selected as the analysis of line. By measuring the intensities of the characteristic spectral line with different Pb concentrations. According to relation between the spectral line intensity and concentration the calibration curves are established. The experimental results show that the spectral line intensity increases linearly with the concentration of Pb under the condition of low concentration,and increases nonlinearly with the concentration of Pb under the condition of high concentration in Gannan navel oranges, of which minimal fitting degree （R2） are 0.95 and 0.98, respectively. The experimental results also show that, LIBS can quickly analyse the relative content of the heavy metal element in the fruit sample, and can be applied in the field related to foodstuff safety.