The use of permeation liquid membranes for free zinc measurements in aqueous solution

A. Gramlich, S. Tandy, V. Slaveykova, A. Duffner, R. Schulin

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11 Citations (Scopus)


The bioavailability of Zn in environmental water phases strongly depends on its speciation. One important species in studies on Zn deficiency or toxicity to organisms is the free ion. The Permeation Liquid Membrane (PLM) technique is a tool to measure free metal concentrations with a short analysis time of 1 h and low costs. However, so far it has only been validated for Cd, Cu, Ni and Pb. In this study we tested the effect of carrier concentrations and pH on Zn transport across the organic PLM membrane and the ability of the technique to measure free Zn in synthetic plant nutrient solution. We found that Zn membrane transport is dependent on the concentration of the carrier molecule lauric acid (LA), whereas variations in the concentration of the other carrier molecule, the crown ether Kryptofix 22DD, showed no effect, suggesting that Zn is not transported via the ⿿classical� PLM transport mechanism by binding to the crown ether. Zn preconcentration increased with increasing pH and decreased with increasing ligand concentrations. Using 0.05 M LA, Zn membrane transport is expected to be rate limiting (permeability criterion
Original languageEnglish
Pages (from-to)429-437
JournalEnvironmental Chemistry
Issue number5
Publication statusPublished - 2012


  • trace-metal speciation
  • natural-water analysis
  • chemical speciation
  • cu(ii) complexes
  • cadmium uptake
  • in-situ
  • transport
  • bioavailability
  • diffusion
  • lability


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