Size exclusion chromatography with online ICP-MS enables molecular weight fractionation of dissolved phosphorus species in water samples

Arjun K. Venkatesan, Wenhui Gan, Harsh Ashani, Pierre Herckes, Paul Westerhoff

Research output: Contribution to journalArticle

5 Scopus citations


Phosphorus (P) is an important and often limiting element in terrestrial and aquatic ecosystem. A lack of understanding of its distribution and structures in the environment limits the design of effective P mitigation and recovery approaches. Here we developed a robust method employing size exclusion chromatography (SEC) coupled to an ICP-MS to determine the molecular weight (MW) distribution of P in environmental samples. The most abundant fraction of P varied widely in different environmental samples: (i) orthophosphate was the dominant fraction (93–100%) in one lake, two aerosols and DOC isolate samples, (ii) species of 400–600 Da range were abundant (74–100%) in two surface waters, and (iii) species of 150–350 Da range were abundant in wastewater effluents. SEC-DOC of the aqueous samples using a similar SEC column showed overlapping peaks for the 400–600 Da species in two surface waters, and for >20 kDa species in the effluents, suggesting that these fractions are likely associated with organic matter. The MW resolution and performance of SEC-ICP-MS agreed well with the time integrated results obtained using conventional ultrafiltration method. Results show that SEC in combination with ICP-MS and DOC has the potential to be a powerful and easy-to-use method in identifying unknown fractions of P in the environment.

Original languageEnglish (US)
Pages (from-to)264-271
Number of pages8
JournalWater Research
StatePublished - Apr 15 2018



  • Dissolved organic carbon
  • ICP-MS
  • Molecular weight distribution
  • Phosphorus
  • Size exclusion chromatography

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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