Square-wave polarographic determination of lead in sea water after coprecipitation enrichment with zirconium hydroxide.

Abstract

Square-wave polarographic determination of lead in sea water after coprecipitation with zirconium hydroxide was investigated. A square-wave polarograph of Shimadzu type PR-50 and Shimadzu type SWP-50 were used and anode was mercury pool in electrolytic cell. Zirconium oxychloride containing 30 mg of zirconium is added to 1000 ml of sea water and pH is adjusted to 8.1 with ammonia water (1: 2). After filtered, the precipitate is then dissolved in 25 ml of 4 M hydrochloric acid. The solution is diluted to 50 ml with distilled water. An aliquot is submitted to the polarographic determination. The polarogram is recorded over the range from-0. 20 V to-0.60 V vs. Hg-pool. The results are as follows: (1) Coprecipitation of lead in sea water was quantitative when the pH was adjusted to 8.1. (2) Lead in sea water was determined to be 3.78 ppb. (3) Effect of diverse ions was examined, and arsenic (III), tin (IV), thallium (I) were found to interfere with the polarographic determination of lead.