基于激光诱导击穿光谱技术的条斑紫菜元素探测研究

Element Detection in Porphyra Yezoensis via Laser-Induced Breakdown Spectroscopy

实验应用激光诱导击穿光谱技术(LIBS)对近海海水中的条斑紫菜进行元素探测。条斑紫菜的光谱表明紫菜中含有Ca、Mg、Mn、Fe、K、P、Na、Zn、Cu、Sr、Si、O、C等元素。为讨论将条斑紫菜作为重金属污染标记物来反映近海海水受污染程度的可行性,制备了4种不同浓度的铅溶液来模拟受污染的近海海水,并将新鲜的条斑紫菜样品浸泡在溶液中。利用LIBS得到这些被污染紫菜的光谱后,采用内标法对其进行定量分析,通过拟合得到校正曲线。为确认定量工作的准确性,计算了实验中等离子体温度和电子数密度,并验证了实验环境满足局域热力学平衡状态。对条斑紫菜光谱中观察到的碳氮(CN)分子带进行了模拟,获得CN分子的两个重要参数,即振动温度和转动温度。最后比较并简要讨论了振动温度、转动温度和等离子体温度。结果验证了LIBS应用于近海污水检测领域的可行性。

Laser-induced breakdown spectroscopy(LIBS) is applied to detect porphyra yezoensis elements in offshore seawater. The spectrum shows that porphyra yezoensis contains Ca, Mg, Mn, Fe, K, P, Na, Zn, Cu, Sr, Si, O, C,and other elements. To investigate the feasibility of using porphyra yezoensis as a marker of heavy metal pollution in offshore seawater to reflect the degree of pollution, four lead solutions with varying concentrations are prepared to simulate polluted offshore seawater in this experiment, and fresh samples of porphyra yezoensis are immersed in the solutions. The spectra of this contaminated porphyra yezoensis are determined using LIBS. Quantitative analysis is performed using the internal standard method. The correction curve is obtained after fitting. The plasma temperature and electron density are calculated in the experiment to confirm the quantitative work’s accuracy as well as the local thermodynamic equilibrium environment is verified. Additionally, CN molecular bands observed in the spectrum of porphyra yezoensis are simulated.Two important parameters of CN molecules are detected: vibrational temperature and rotational temperature. Finally,vibrational temperature, rotational temperature, and plasma temperature are compared and discussed briefly. The results verify the feasibility of applying LIBS to the field of offshore sewage detection.