Nowadays, detecting metals dissolved in water is a paramount health concern, due to the sustained contamination of water reservoirs for human consumption. Limits of detection in the sub-ppm range are required, but a simple and fast method suitable to measure such levels is not easy to implement. Laser induced breakdown spectroscopy (LIBS) is a simple technique and can be employed on field, but its lack of sensitivity at sub-ppm has restricted its application. With the recent use of metallic nanoparticles to enhance the plasma emission, ppb limits of detection are achieved. In combination with liquid droplet acoustic levitation, this work demonstrate that few ppb limit of detection is possible measuring directly in the liquid sample without any pretreatment. When limits of detection obtained with and without the use of metallic nanoparticles are compared, improvements up to three orders of magnitude were obtained for aluminum dissolved in water, keeping similar relative standard deviations in the range of 10–20%. It is also important to note that after optimization, excitation energies as low as 1 mJ are sufficient to generate spectra with signal to noise ratios around 7 at concentrations below 1 ppb. The resulting spectra are suitable to be analyzed for quantification, opening the real possibility of its implementation on field applications.

如今，由于供人类消费的水库持续受到污染，因此检测水中溶解的金属是一个最重要的健康问题。需要亚 ppm 范围内的检测限，但适用于测量此类水平的简单快速方法并不容易实施。激光诱导击穿光谱 (LIBS) 是一种简单的技术，可以在现场使用，但其在亚 ppm 级缺乏灵敏度限制了其应用。随着最近使用金属纳米粒子来增强等离子体发射，达到了 ppb 的检测限。与液滴声悬浮相结合，这项工作表明，在没有任何预处理的情况下直接在液体样品中测量几乎没有 ppb 的检测限是可能的。当比较使用和不使用金属纳米粒子时获得的检测限时，溶解在水中的铝获得了三个数量级的改进，保持了类似的相对标准偏差在 10-20% 的范围内。同样重要的是要注意，优化后，低至 1 mJ 的激发能量足以在浓度低于 1 ppb 时生成信噪比约为 7 的光谱。由此产生的光谱适合进行定量分析，开启了其在现场应用中实施的真正可能性。低至 1 mJ 的激发能量足以在浓度低于 1 ppb 时生成信噪比约为 7 的光谱。由此产生的光谱适合进行定量分析，开启了其在现场应用中实施的真正可能性。低至 1 mJ 的激发能量足以在浓度低于 1 ppb 时生成信噪比约为 7 的光谱。由此产生的光谱适合进行定量分析，开启了其在现场应用中实施的真正可能性。