Conceal disturbing elements like iron,copper,lead with hydrogen fluoride amine-EDTA,add the potassium iodide to separate iodine, and take starch as indicator,titrate with sodium hyposulfite.

• 试样以王水分解、泡塑富集分离金,硫脲解脱,以硝酸-硫酸破坏硫脲,用氟化氢胺-EDTA掩蔽铁、铜、铅等干扰元素,加碘化钾使之析出碘,以淀粉为指示剂,用硫代硫酸钠进行滴定。