This paper describes the effects of laser pulse rate and solution flow rate on the determination of lithium at high pressure for water and 2.5% sodium chloride solutions using laser-induced breakdown spectroscopy (LIBS). Preliminary studies were performed with 0–40 mg L⁻¹ Li solutions, at ambient pressure and at 210 bar, and in static and flowing (6 mL · min⁻¹) regimes, for a combination of four different measurement conditions. The sensitivity of calibration curves depended on the pressure and the flow rate, as well as the laser pulse rate. The sensitivity of the calibration curve increased about 10% and 18% when the pressure was changed from 1 to 210 bar for static and flowing conditions, respectively. However, an effect of flow rate at high pressure for both 2 and 10 Hz laser pulse rates was observed. At ambient pressure, the effect of flow rate was negligible, as the sensitivity of the calibration curve decreased around 2%, while at high pressure the sensitivity increased around 4% when measurements were performed in a flow regime. Therefore, it seems there is a synergistic effect between pressure and flow rate, as the sensitivity increases significantly when both changes are considered. When the pulse rate is changed from 2 to 10 Hz, the sensitivity increases 26–31%, depending on the pressure and flow conditions. For lithium detection limit studies, performed with a laser pulse energy of 2.5 mJ, repetition rate of 10 Hz, gate delay of 500 ns, gate width of 1000 ns, and 1000 accumulations, a value around 40 µg L⁻¹ was achieved for Li solutions in pure water for all four measurement conditions, while a detection limit of about 92 µg L⁻¹ was determined for Li in 2.5% sodium chloride solutions, when high pressure and flowing conditions were employed. The results obtained in the present work demonstrate that LIBS is a powerful tool for the determination of Li in deep ocean conditions such as those found around hydrothermal vent systems.

本文描述了激光脉冲速率和溶液流速对使用激光诱导击穿光谱 (LIBS) 在高压下测定水和 2.5% 氯化钠溶液中锂的影响。使用 0–40 mg L ^-1 Li 溶液、环境压力和 210 bar 以及静态和流动 (6 mL · min ^-1) 制度，用于四种不同测量条件的组合。校准曲线的灵敏度取决于压力和流速，以及激光脉冲速率。在静态和流动条件下，当压力从 1 巴变为 210 巴时，校准曲线的灵敏度分别增加了约 10% 和 18%。然而，观察到高压下流速对 2 赫兹和 10 赫兹激光脉冲速率的影响。在环境压力下，流速的影响可以忽略不计，因为校准曲线的灵敏度降低了约 2%，而在高压下，当在流动状态下进行测量时，灵敏度增加了约 4%。因此，压力和流量之间似乎存在协同效应，因为当考虑这两种变化时，灵敏度会显着增加。当脉搏率从 2 Hz 变为 10 Hz 时，灵敏度会增加 26-31%，具体取决于压力和流量条件。对于锂检测限研究，使用 2.5 mJ 的激光脉冲能量、10 Hz 的重复频率、500 ns 的门延迟、1000 ns 的门宽和 1000 次累积进行，值约为 40 µg L在所有四种测量条件下，纯水中的 Li 溶液均达到^-1，而当采用高压和流动条件时，Li 在 2.5% 氯化钠溶液中的检测限约为 92 µg L ^-1。目前工作中获得的结果表明，LIBS 是在深海条件（例如在热液喷口系统周围发现的条件）中测定锂的有力工具。