Spectrophotometric determination of micro bismuthIIIin copper-base alloy with new reagent 2,6-dibromo-4-chloro-carboxylarsenazo

The color reaction of 2,6-dibromo-4-chloro-carboxylarsenazo (DBCCA) with bismuth*#has been studied in detail.In the mixed medium of sulfuric and phosphoric acid,bismuth reacts with DBCCA sensitively and selectively to form a blue complex,which has a maximum absorptive peak at 643nm with an apparent molar absorptivity being 2.031×10 5L.mol -1 .cm -1 . Beer′s law is obeyed in the range of 0-25μg/25mL for bismuth*#. The reaction of bismuth*#with DBCCA is rapid and the absorbance of complex can be stable for at least 24h.Moreover,the proposed method has very good selectivity,especially a large amount of copper can be tolerated.So it has been applied to determine bismuth directly in copper-base alloy.