Application of Ag2X (X = SO3, Cr2O7, C2O4 and CO3) solid-phase reagents for indirect determination of cyanide in the industrial effluent using FIA-FAAS system

Four solid-phase reagents have been tested for indirect determination of cyanide using flow injection analysis-flame atomic absorption spectrometry (FIA-FAAS). The method is based on insertion of aqueous cyanide solutions into an on-line Ag₂X (where X are SO₃²⁻, Cr₂O₇²⁻, C₂O₄²⁻ and CO₃²⁻) packed column (25%, m/m suspended on silica gel beads) and re-distilled water or sodium hydroxide are used as the carrier stream. The eluent containing the analyte as silver cyanide complexes, produced from reaction between Ag₂X and cyanide, measured by flame atomic absorption spectrometry. The method is simple, fast and selective than other published FIA procedures. A relative standard deviation (R.S.D.) better than 1.12% was obtained in a repeatability study. The method was applied to the determination of cyanide in industrial electrolytic baths.