锂同位素（Li）作为有效的地球化学示踪剂，受到地质学家长期关注。利用激光剥蚀-多接收电感耦合等离子体质谱（LA-MC-ICP-MS）原位微区分析单矿物颗粒在微米尺度上的Li同位素组成，可以对了解特定的地质演化过程提供独特的视角和证据，提供全岩分析不能获取的信息。然而，单矿物地质样品中Li同位素的原位微区准确测定主要受限于其较低的信噪比以及基体匹配参考物质的缺乏。本课题拟通过优化飞秒激光(fs-LA)条件、提高接口处真空度、采用较高的放大器电阻以及NaCl降低Li背景的方法提高Li的信噪比，从而进一步提高Li同位素原位微区分析的空间分辨率。此外，结合岩石纳米颗粒制备技术和高温熔融技术制备基体匹配的单矿物参考物质，降低基体效应的影响，提高Li同位素测定的准确度和精度。在此研究基础上，最终实现fs-LA-MC-ICP-MS对单矿物中Li同位素的原位微区高精度高空间分辨率准确测定。

The lithium (Li) isotope system has been widely used as a key tracer in geosciences. In-situ microanalysis of Li isotopic ratio in mineral grain by LA-MC-ICP-MS can provide a unique perspective and evidence to explore the geological processes. However, the in-situ microanalysis of Li isotopic ratio in mineral grain is hampered by the lack of matrix-matched reference materials and low signal-noise ratio. This project intends to increase the signal-noise ratio of the technique by optimizing the parameters and conditions of femtosecond laser ablation system, improving the degree of vacuum at the interface, applying the higher amplifier resistance of Faraday cup and using NaCl wash solution. In order to reduce the matrix effect, we also intend to synthesize some mineral grain standard materials by using nanoparticle preparation technology and high-temperature melting technology. Based on the above researches, the fs-LA-MC-ICP-MS can be finally used to determine the Li isotopes in single minerals with high precision, high accuracy and high spatial resolution.