受到液体内部复杂环境因素的影响,LIBS技术在针对液体样品的成分检测分析的应用受到很大的制约.文章提出了一种由超声波雾化器件辅助,先将液体雾化成空气中密集的雾状小液滴,然后进行LIBS检测的新方法.并依据此思路实现了一套由超声波雾化器、Nd∶YAG激光器(1 064 nm)和ICCD探测器组成的检测系统.使用该系统对溶解有镁元素的水溶液样品进行了系统实验分析.实验发现,即使在相对较低的脉冲能量(30 mJ)下,该方法诱导的LIBS信号仍具有较长的寿命和较高的信背比.该方法对Mg元素的检测限能够达到0.242 ppm(10-6 g·g-1)量级.同时,文章还利用Ha线对等离子体的电子密度进行了计算,分析了等离子体演化的特点.%Because of the complex factors in bulk water, the effect ofLIBS on the analysis of liquid sample is limited in liquid sample. Under this circumstances, a new method of LIPS assisted by ultrasonic nebulizing technology has been introduced.According to this method, the liquid sample is transformed into dense droplets by ultrasonic nebulizing technology, and these dense droplets are subjected to the analysis of LIBS later. Based on this thought, a detection experimental system was established, composing of ultrasonic system, 1 064 nm ND: YAG laser, and ICCD system. A series of experiments and analysis were carried out to detect the magnesium element dissolved in pure water using the detection experimental system mentioned above. The results showed that even with a very low laser pulse energy (30 mJ), the signals of LIBS still have a long lifetime and a high signal to background ratio. The limit of detection for magnesium element could reach as low as 0. 242 ppm. At the same time, the electron density of plasma was calculated utilizing the Ha line to give the evolution features of plasma induced by this new method.
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