Elimination of the copper-zinc interference at mercury film electrodes by a Nafion/clay modified

The construction of a Nafion/clay-modified mercury electrode was shown to s uccessfully eliminate the interference of Cu2+ in the stripping determinati on of Zn2+. The modified electrode discriminated towards deposition of Cu2 during the electrolytic deposition of Zn2+ thus it avoided the formation o f the intermetallic compounds at mercury. Square-wave stripping peak curren ts after 1 min of electrolysis at -1.2 V revealed that the Zn-stripping sig nal obtained with the modified electrode was linear over two ranges of 0-5 and 6-12 muM for Zn2+ in the presence of 10 muM Cu2+. The modification proc edure is reproducible and the resulting attachment is stable. The analytica l utility is illustrated by the measurement of Zn2+ in real water samples.