Sensitive determination of domoic acid in shellfish by on-line coupling of weak anion exchange solid-phase extraction and liquid chromatography-diode array detection-tandem mass spectrometry

► First application of on-line SPE for determination of domoic acid in shellfish. ► Selective cleanup of domoic acid by weak anion exchange SPE. ► On-line SPE allowed pre-concentration of large volume injections. ► LODs in the sub-nanogram per gram level are achieved. ► Domoic acid in shellfish samples from North-western Spain and Northern Chile.