示波极谱滴定法测定显影液中米吐尔和对苯二酚含量

Determination of Metol and p Dihydroxybenzene in Developing Agent by Oscillographic Titration

用 1 .5mol/ L 乙酸铵 -氨 ( p H8.2 ) -无水乙醇 ( 2∶ 1 ,V/ V)混合溶液为极谱底液 ,以 K2 Cr O4 与米吐尔和对苯二酚的氧化还原反应为基础 ,用 K2 Cr O4 作滴定剂 ,以示波极谱图上 Cr O2 - 4切口出现指示终点 ,测定显影液中米吐尔和对苯二酚的含量。本法简便易行 ,灵敏准确 ,终点直观 ,应用于 D- 72和 D- 76显影液中米吐尔和对苯二酚的测定 ,获得满意结果。

This method is based on the oxidation reduction reactions CrO 2- 4 with metol ( p methylaminophanol sulfate), P Dihydroxybenzene in developing agent. In 1 5 mol/L NH 4Ac NH 4OH(pH 8.2) C 2H 5OH(2∶1, V/V )solution, CrO 2- 4 titrates component in the sample. The appearance of CrO 2- 4 incision can be used to indicate the end point of reaction. The method is simple, accurate and sharp.