Definition

A laboratory technique that combines two different processes to separate, identify, and measure the amount of different substances in a liquid sample. In the liquid chromatography (LC) part of the process, a liquid sample is passed through a column filled with a material that separates the different substances in the sample. In the mass spectrometry (MS) part of the process, the separated substances then pass through a special machine that reports the molecular weight, structure, identity, and number of different substances in the sample. LC-MS has many uses, including screening for drugs, identifying toxins in the environment, and detecting certain metabolic disorders in infants. Also called liquid chromatography–mass spectrometry.