褪色光度法测定自来水中余氯

Determination of Chlorine in Water Supply by Decolour Spectrophotometry

利用氯酸钾和浓盐酸所产生的氯氧化甲基橙使其褪色 ,建立了一种测定自来水中余氯的新方法。最大吸收波长为 51 0 nm,表观摩尔吸光系数 ε510 =3.4× 1 0 4 L.mol-1.cm-1,氯量在 1 2 .5～37.5μg/2 5m L范围内服从比耳定律。该方法用于自来水中余氯的测定 。

A new method fordetermination of the chlorine in water supply was found.Ituses KCl O3reac- tion with concentrated HCl to produce chlorine which can have methyl orange decoloured.The maximum absorption wave length is at 51 0 nm with an apparent molar absorptivity 3.4× 1 0 4 L .mol-1.cm-1. Beer′s law is obeyed in the range of1 2 .5～ 37.5μg/2 5m L of chlorine.The method has been applied to the deter- mination of chlorine in water supply with satisfactory results.