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

摘要: Abstract Arsenic (As) can form complexes with dissolved organic matter (DOM), which affects the fate of arsenic in waste sites and natural environments. It remains a challenge to analyze DOM-bound As, particular by using direct chromatographic separation method. Size exclusion chromatography (SEC) hyphenated UV spectrophotometer inductively coupled plasma mass spectrometry (ICP-MS) was developed characterize complexation arsenite (As III ) DOM. This SEC–UV-ICP-MS method is able differentiate As –DOM from free species has advantage determination both through mild separation. The suitability this for studying demonstrated its application, combination Scatchard plot nonlinear regression ligand binding model, characterizing humic acid (HA) absence or presence sand. results suggest that, consistent polyelectrolytic nature HA, –HA should be accounted multiple classes sites. By loosely classifying into strong (S1) weak (S2) sites, apparent stability constants ( K s resulting As–DOM were calculated as log  1  = 6.5–7.1 while 2  = 4.7–5.0.