Solid Phase Extraction and Spectrophotometric Determination of Trace Gold Using 5-(4-Carboxylphenylazo)-8-hydroxyquinoline

摘要

Synthesis and application of 5-(4-carboxylphenylazo)-8-hydroxyquinoline(5-CPAHQD)as a new chromogenic reagent for determination of gold has been described.Highly sensitive,selective,and fast method for determination of gold based on its rapid reaction with 5-CPAHQD and solid phase extraction of colored chelate on C12 phase(DODECYL cartridge)has been developed.In the presence of 0.005-0.1 mol L~(-1)phosphoric acid solution and cetyl trimethyl ammonium bromide medium,5-CPAHQD reacted with gold to form salmon-pink chelate of gold-to-5-CPAHQD molar ratio of 1:3.The chelate C12 was eluted from the cartridge with ethanol.Enrichment factor of 50 was achieved.In ethanolic medium molar absorptivity of the chelate was 1.99 x 10~5 L mol~(-1)cm~(-1)at 520 nm.Beer's law was obeyed in the range of 0.01-1.2 mu g mL~(-1).Relative standard deviation for eleven replicate determinations of 0.6 mu g mL"' concentration was 1.21 %.In the original sample detection limit was 0.01 mu g L~(-1).The proposed method was applied to determination of trace gold in ore samples with good result.