PlumX Metrics
Embed PlumX Metrics

Development and evaluation of a diffusive gradients in a thin film technique for measuring ammonium in freshwaters

Analytica Chimica Acta, ISSN: 0003-2670, Vol: 904, Page: 83-91
2016
  • 38
    Citations
  • 0
    Usage
  • 44
    Captures
  • 0
    Mentions
  • 0
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

  • Citations
    38
    • Citation Indexes
      38
  • Captures
    44

Article Description

A new diffusive gradients in a thin film (DGT) technique, using Microlite PrCH cation exchange resin, was developed and evaluated for measuring NH 4 –N in freshwaters. Microlite PrCH had high uptake (>92.5%) and elution efficiencies (87.2% using 2 mol L −1 NaCl). Mass vs. time validation experiments over 24 h demonstrated excellent linearity (R 2  ≥ 0.996). PrCH-DGT binding layers had an extremely high intrinsic binding capacity for NH 4 –N (∼3000 μg). NH 4 –N uptake was quantitative over pH ranges 3.5–8.5 and ionic strength (up to 0.012 mol L −1 as NaCl) typical of freshwater systems. Several cations (Na +, K +, Ca 2+ and Mg 2+ ) were found to compete with NH 4 –N for uptake by PrCH-DGT, but NH 4 –N uptake was quantitative over concentration ranges typical of freshwater (up to 0.012 mol L −1 Na +, 0.006 mol L −1  K +, 0.003 mol L −1 Ca 2+ and 0.004 mol L −1  Mg 2+ ). Effective diffusion coefficients determined from mass vs. time experiments changed non-linearly with electrical conductivity. Field deployments of DGT samplers with varying diffusive layer thicknesses validated the use of the technique in situ, allowed deployment times to be manipulated with respect to NH 4 –N concentration, and enable the calculation of the diffusive boundary layer thickness. Daily grab sample NH 4 –N concentrations were observed to vary considerably independent of major rainfall events, but good agreements were obtained between PrCH-DGT values and mean grab sample measurements of NH 4 –N ( C DGT : C SOLN 0.83–1.3). Reproducibility of DGT measurements in the field was good (relative standard deviation < 11%). Limit of detection was 0.63 μg L −1 (equivalent to 0.045 μmol L −1 ) based on 24 h deployments.

Bibliographic Details

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know