Liquid chromatography separates analytes according to their chemical affinity, while the mass spectrometer measures the mass of ionized molecules and their fragments. The coupling of these two analytical techniques makes it possible to quantify micropollutants present in water, sludge, and solids at concentrations below one nanogram per litre.

Ultra-performance liquid chromatography (UPLC, Acquity Premier, Waters) allows the use of a wide range of solvents and columns depending on the molecules being analyzed. It operates at very high pressures of up to 1,000 bar. This extremely high pressure, combined with highly efficient chromatographic columns, enables the separation of molecules with very similar chemical structures, such as isomers.

The mass spectrometer (TQ Absolute, Waters) is equipped with a triple quadrupole system. This technology allows to select a target molecule (precursor ion), fragment it, and then specifically detect the resulting fragments (product ions). This double selection ensures very high specificity together with exceptional sensitivity, allowing quantification limits below one nanogram per litre.