He Yage, Wang Xianshuang, Guo Shuai, Li Angze, Xu Xiangjun, Wazir Nasrullah, Ding Chunjie, Lu Tianqi, Xie Lingling, Zhang Min, Hao Yan, Guo Wei, Liu Ruibin
Appl Opt. 2019 Jan 10;58(2):422-427. doi: 10.1364/AO.58.000422.
Lithium (Li), as the lightest metal and the most important powerful material in battery fabrication, is widely used in many fields. The fast detection of Li is necessary for industrial application. The slow-speed detection methods, including atomic absorption spectroscopy and inductively coupled plasma mass spectroscopy with high accuracy and low limit of detection, are hard to utilize in in situ industrial control due to complex prepreparation of samples. Here, through the analysis of the typical spectrum line at Li I 670.79 nm, Li ions in water were detected quantitatively in 1 min, including sample preparation by laser-induced breakdown spectroscopy (LIBS) with filter paper as the adsorption substrate. The calibration curve by polynomial function fitting is used to predict the Li concentration. The limit of detection (LOD) as low as 18.4 ppb is obtained, which is much lower than the results ever reported by using filter paper. The related factor R reaches 99%, and the prediction error is lower than 2%, proving the fast and online monitor for Li by LIBS is feasible. Furthermore, by comparison with the results with filter paper enrichment, the Li detection from water directly shows higher LOD to 10.5 ppm. Moreover, the plasma images, by gate-controlled intensified charge-coupled device, illustrate a different morphology and evolution between that on water surface and filter paper surface through visual observation. This study provides experimental and theoretical experience in a fast way for the quantitative detection of the lightest metal ion (Li) in liquid.
锂（Li）作为最轻的金属以及电池制造中最重要的关键材料，在许多领域都有广泛应用。快速检测锂对于工业应用而言至关重要。诸如原子吸收光谱法和电感耦合等离子体质谱法等低速检测方法，虽具有高精度和低检测限，但由于样品预处理复杂，难以用于现场工业控制。在此，通过对锂 I 670.79 nm 处典型谱线的分析，利用以滤纸为吸附基质的激光诱导击穿光谱法（LIBS）进行样品制备，在 1 分钟内对水中的锂离子进行了定量检测。采用多项式函数拟合的校准曲线来预测锂浓度。获得了低至 18.4 ppb 的检测限，这比以往使用滤纸所报道的结果要低得多。相关系数 R 达到 99%，预测误差低于 2%，证明了利用 LIBS 对锂进行快速在线监测是可行的。此外，与滤纸富集的结果相比，直接从水中检测锂时的检测限更高，达到 10.5 ppm。而且，通过门控增强型电荷耦合器件获得的等离子体图像，经视觉观察表明水面和滤纸表面的等离子体形态和演化有所不同。本研究为快速定量检测液体中最轻金属离子（Li）提供了实验和理论经验。
