Spectrophotometric Determination of Gold in Water and Ore with 2-Carboxyl-1-Naphthalthiorhodanine

摘要

This paper reports on the synthesis of a new chromogenic reagent,2-carboxyl-1-naphthalthiorhodanine (CNTR).A high sensitive,selective,and rapid method for the determination of gold based on the rapid reaction of gold with CNTR and the solid phase extraction of the colored chelate with a reversed phase polymer-based C_(18) cartridge was developed.In the presence of 0.05-0.5 mol L~(-1) of phosphoric acid solution and emulsifier-OP medium,CNTR reacts with gold to form a red chelate of a molar ratio 1:3 (gold to CNTR).This chelate was enriched by the solid phase extraction with a polymer-based C_(18) cartridge and the retained chelate was eluted from the cartridge with dimethyl formamide (DMF).The enrichment factor of 100 was achieved.In the DMF medium,the molar absorptivity of the chelate is 1.35 x 10~5L mol~(-1) cm~(-1) at 540 nm.Beer's law is obeyed in the range of 0.01 approx 2 mu gmL~(-1) in the measured solution.The relative standard deviation for 11 replicates sample of 0.5 mu g L~(-1) level is 2.05%.The detection limit,based on three times the standard deviation is 0.02 mu g L~(-1) in the original sample.This method was applied to the determination of gold in water and ore with good results.