In LC-MS, a liquid sample is injected into a high-performance liquid chromatography (HPLC) system, once separated, the individual compounds elute from the column and enter the mass spectrometer.

In the mass spectrometer, the compounds are ionized, creating charged particles. These ions are then accelerated into the analyzer, where they are sorted based on their mass to charge ratio. This highly sensitive detection technique provides detail on the structure of compounds present in the sample.

LC-MS offers high sensitivity and selectivity, making it suitable for the analysis of complex samples containing a wide range of compounds. By first running a set of calibration samples of a known composition, this technique can be used to determine the composition of samples to an extremely high level of accuracy.