Spectrophotometric determination of small amounts of tin in lead and antimonial lead alloys

Abstract

A method is described for the determination of 0·001 to 0·10 per cent. of tin in lead and antimonial lead alloys. The sample (0·25 to 2·5 g) is dissolved in a mixture of nitric and citric acids. After addition of EDTA and ammonium chloride, the pH of the solution is adjusted to 5·5 with ammonia solution before passing it through a column containing silica gel. Tin is adsorbed on the column, while lead, antimony and other metals pass through. After elution with hydrochloric acid solution the tin is determined spectrophotometrically with gallein. The standard deviation on samples containing 0·0051 and 0·038 per cent. of tin is ±0·0005 and ±0·002, respectively. At least eight determinations can be carried out in 1 day.