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。

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