Abstract: The zinc flue dust sample was digested by HCl-HNO₃-HF and the indium content was directly measured by a single-sweep polarography in the supporting electrolyte solution of HCl-HONH₃Cl. The effect of reagent dosage and some interference ions were studied，and the suitable conditions were selected. The experimental results show that a sensitive polargraphic wave of indium complex is produced at -0.63 V (vs. SCE), whose peak current has a good linear relationship with indium concentration in the rang of 0.01~5  g/mL，with the detection limit being 0.003  g/mL. This method is simple，rapid，sensitive and accurate. When it was used for direct determination of micro-amount indium in flue dust of zinc smelting samples，the RSD was 0.5%~2.7 % and the recovery was in the range of 98%~104%，with the results agreeing with those obtained by ICP-AES.

Key words: Zinc flue dust, Indium determination, Single-sweep polarography