本文研究了稀硫酸溶液中,痕量锑(Ⅲ)催化高碘酸钾氧化中性红褪色的新指示反应,其反应的表观活化能=127.6kJ/mol,表观速率常数为1.92×10~(-3)/s,半衰期6.02min,并为一级反应,建立了直接光度法测定超痕量锑(Ⅲ)的新方法,操作简单、快速。本方法灵敏度为4.2×10~(-12)g Sb(Ⅲ)/mL,测定范围0～0.2μg Sh(Ⅲ)/25mL,并用以测定人发中Sb(Ⅲ),获得了满意结果。 In this paper, a new indication reaction of dilute sulfuric acid solution with trace antimony (Ⅲ) catalyzed oxidation of neutral red by potassium periodate was studied. The apparent activation energy of the reaction was 127.6 kJ / mol and the apparent rate constant was 1.92 × 10 ~ (-3) / s, and the half-life of 6.02min, and the first order reaction. A new method for the direct spectrophotometric determination of ultra-trace antimony (Ⅲ) was established, which was simple and rapid. The sensitivity of the method was 4.2 × 10 ~ (-12) g Sb (Ⅲ) / mL, and the determination range was 0 ~ 0.2μg Sh (Ⅲ) / 25mL. The method was applied to the determination of Sb (Ⅲ) in human hair and satisfactory results were obtained.