检测水样或废水中的游离氯或总氯含量

200 ml sample (measuring cylinder; for chlorine concentrations > 2 mg/l use less sample and fill up with dist. water to 200 ml) are filled into a 250 ml beaker. Add 1 ml KI solution and 1 ml buffer solution pH = 4.0 and titrate with the phenylarsine oxide to an equivalence point (potentiometry) or μA endpoint (amperometry)