Determination of trace sulfur in antimony by ion chromatography with adsorption column of alumina

A novel method of determining trace amount of sulfur in antimony with alumina adsorption column-ion chromatography was established.Antimony samples were dissolved by aqua regia,hydrobromic acid,and hydrochloric acid step wisely,converting sulfur in the samples into sulfate.Elimination of Antimony matrix,as its halides evaporated,was conducted at low temperature on a hot plate during the sample digestion.After sample solution flowed through alumina absorption column,sulfate was concentrated on the column and separated from other potential interferences.The desorption of sulfate in the column was achieved by rinsing with diluted ammonia.The sulfate in the rinsed solution was determined by ion chromatography afterwards.The experimental conditions,such as composition and flow rate of eluent,were optimized.The combination of sodium carbonate of 3.5 mmol/L and sodium bicarbonate of 1.0 mmol/L was used as an eluent with the flow rate of 1.2 mL/min.The dynamic linearity located between 0.2～100 μg/mL,the detection limit of the method was 0.2 μg/mL.And the recoveries were 92.9%～103.1%.The proposed method is fast,accurate and sensitive.This method is suitable to determine sulfur in antimony with satisfactory results.