Studying arsenite-humic acid complexation using size exclusion chromatography-inductively coupled plasma mass spectrometry

► A novel SEC-UV-ICP-MS method was developed to directly determine DOM-bound As. ► This method was applied to characterize arsenite complexation with humic acid. ► Heterogeneous binding sites with varying stability for arsenic are present in DOM. ► Promising potential was demonstrated for this method in studying As-DOM interactions.