Spectrophotometric assay of POE nonionic surfactants and its application to surfactant sorption isotherms

Derick G. Brown, Peter R. Jaffe

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25 Scopus citations


The operational range and suitability toward environmental samples of an iodine-iodide (I-I) assay for nonionic surfactants were assessed. The I-I assay provides a rapid and repeatable method for determining aqueous nonionic surfactant concentrations. Through a systematic examination of surfactant structure, the operational range of the assay was shown to be on the order of 10-6 to 10-3 MEO, where the concentration unit MEO is defined as the molar surfactant concentration multiplied by the number of ethylene oxide units in the surfactant molecule. For environmental samples, it was shown that the I-I assay can be applied to measurement of surfactant sorption isotherms to aquifer sands and bacteria cultures. A potential limitation of the I-I assay is interference with humic acids, with the magnitude of the interference dependent on the concentration of humic acids present. The main benefit of the I-I assay is that its high accuracy and ease of application allows measurement of low levels of surfactant sorption. Surfactant sorption to aquifer sand could be measured down to the range of 10-9 mol/g.

Original languageEnglish (US)
Pages (from-to)2022-2025
Number of pages4
JournalEnvironmental Science and Technology
Issue number10
StatePublished - May 15 2001

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Environmental Chemistry


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