液相色谱法-质谱联用（英语：Liquid chromatography–mass spectrometry，简称液质联用，英文缩写LC-MS或HPLC-MS）是一种将高效液相色谱（High performance liquid chromatography，简称HPLC)的物理分离能力和质谱（mass spectrometry，简称MS）的质量分析能力结合起来的分析化学技术。LC-MS是一项具有非常高的敏感度和选择性的非常强有力的分析技术，它使用于很多的领域。一般说来，它的使用方向是在多种其他化合物从在的复合混合物中，测出各种组分并有可能确定其详细结构。 LC-MS在尿液中药物筛选分析中的局限性在于它常常不能区分特定的代谢产物，特别是对于氢可酮及其代谢物尤为明显。LC-MS尿液分析测试仅测定特定类别的药物，对于有些药物及其代谢物的测定需要用气相色谱法-质谱联用（Gas chromatography-mass spectrometry，简称 GC-MS)

Liquid chromatography–mass spectrometry (LC-MS, or alternatively HPLC-MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (or HPLC) with the mass analysis capabilities of mass spectrometry (MS). LC-MS is a powerful technique that has very high sensitivity, making it useful in many applications. Its application is oriented towards the separation, general detection and potential identification of chemicals of particular masses in the presence of other chemicals (i.e., in complex mixtures), e.g., natural products from natural-products extracts, and pure substances from mixtures of chemical intermediates. Preparative LC-MS systems can be used for rapid mass-directed purification of specific substances from such mixtures that are important in basic research, and pharmaceutical, agrochemical, food, and other industries.