electrospray ionisation tandem mass spectrometry high-performance liquid chromatography-electrospray ionisation tandem mass spectrometry HPLC-ESI-MS2 high pressure liquid chromatography electrospray ionisation tandem mass spectroscopy high performance liquid chromatography electrospray ionisation tandem mass spectrometry CHMO:0000578 HPLC ESI MS-MS high pressure liquid chromatography electrospray ionization tandem mass spectroscopy HPLC-ESI-MS-MS HPLC ESI MS/MS high performance liquid chromatography electrospray ionisation tandem mass spectroscopy A method where the sample mixture is first separated by high-performance liquid chromatography before being ionised by forcing a solution (usually in an organic solvent) of it through a small heated capillary (at a flow rate of 1–10 uL min1) into an electric field to produce a very fine mist of charged droplets. The ions are then characterised according to mass-to-charge ratio and relative abundance by two mass spectrometers in series. HPLC-ESI-MS/MS