激光诱导击穿光谱(LIBS)已成功地运用于固体、 液体、 气体样品中微量元素的测量以及微生物、 细菌等的鉴别分析上, 而在植物样品上面的应用则是一个较新的课题。 该实验用纳秒Nd∶YAG激光器击穿真空冻干的土豆、 百合样品, 用光纤光谱仪测量了其LIBS光谱。 通过鉴别、 分析LIBS光谱, 得到了这两种样品中微量元素的成分。 并且对土豆干和百合干中Ca, Na, K, Fe, Al, Mg六种金属元素典型谱线的强度进行了统计分析, 并由此得到了样品中这六种微量元素含量的对比情况。 实验结果表明土豆干中的Ca和Na等含量都明显高于百合干, 而百合干中Mg的含量较高。 实验结果还表明用LIBS技术检测、 对比冻干植物样品中微量元素含量是一种快速、 有效的分析方法。

A LIBS setup was built in the Institute of Modern Physics. In our experiments, LIBS spectra produced by infrared radiation of Nd∶YAG nanosecond laser with 100 and 150 mJ pulse energy, respectively, were measured by fiber optic spectrometer in the ranges of 230-430 nm and 430-1 080 nm with a delay time of 1.7 and gate width of 2 ms for potato and lily samples prepared by vacuum freeze-dried technique. The lines from different metal elements such as K, Ca, Na, Mg, Fe, Al, Mn and Ti, and nonmetal elements such as C, N, O and H, and some molecular spectra from C2, CaO, and CN were identified according to their wavelengths. The relative content of the six microelements, Ca, Na, K, Fe, Al, and Mg in the samples were analyzed according to their representative line intensities. By comparison we found that there are higher relative content of Ca and Na in lily samples and higher relative content of Mg in potato samples. The experimental results showed that LIBS technique is a fast and effective means for measuring and comparing the contents of microelements in plant samples.