A very sensitive and rapid potentiometric determination of trace chlorine in water is described. The method is based on the transient potential changes which appears during the reduction of dissolved chlorin with an iron(III)/iron(II) potential buffer containing chloride and sulfuric acid. The sample is injected into a water carrier stream and merged with a stream of this potential buffer solution; chlorine is reduced during passage through a short reaction coil. The potential change from the baseline is measured with a flow-through ORP (oxidation-reduction potential) electrode. Potential changes (peak heights) are proportional to chlorine concentrations from 10-7 M to 10-5 M. The detection limit is 5 × 10-8 M (3.5 μgl-1 as Cl2). The sample throughput is 45 h-1. Reproducibility is in the range 2.5-1.1%. Results for potable water agree with those obtained by the o-tolidine method.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Environmental Chemistry