Collect. Czech. Chem. Commun. 1999, 64, 1966-1974

Gas/Diffusion Flow Injection Determination of Ammonium Ions in River and Waste Waters by Conductometry

Jiří Vlček and Vlastimil Kubáň*

Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Zemědělská 1, CZ-613 00 Brno, Czech Republic


An FIA conductometric method for monitoring of ammonium ions in river and waste waters is proposed. A very good detection limit (xD 5.6 μmol l-1) was obtained at 100/20 s preconcentration/rinsing times and 2 ml sample consumption per analysis at the flow rate 0.8 ml min-1. The detection limit xD can be further improved at longer preconcentration/ rinsing times. Precipitation of polyvalent metal ions (mainly Fe(III)) was eliminated by addition of 0.5 mmol l-1 EDTA prior to injection. The results are comparable with those obtained by spectrophotometry (Nessler's reagent).

Keywords: Ammonium; Flow injection analysis; Gas diffusion; River water; Waste water; Conductometry; Electrochemistry.