Chromatographic methods applied to the separation and determination of some metals
A method is detailed for the determination of lead, -antimony and tin which is based on the separation of the antimony and tin by means of anion exchange resins using malonic acid as elutriant. In the presence of malonic acid these elements form anion complexes, the tin being held by the resin while antimony «nd lead pass through the column. Investigations of the ion-exchange equilibria have shown that the separation factor is high and it is claimed that the method constitutes the first widely applicable method for these elements using anion exchange. All three elements are determined colorimetrically after separation, antimony as iodoantimonate, lead with dithizone reagent, and tin (after elution from the ion-exchange column with 9K sulphuric acid) as iodostannate. The colorimetric determination of tin is a development from this work and it is suggested that the method might form the basis for the determination of a range of metals. The proposed method is also rapid, capable of use by relatively inexperienced operators and is particularly suitable for the analysis of White Metals, Bewter metals and other lead or tin alloys. Results of the analysis of a number of alloys are more reliable than those by classical methods and the method is capable of application over a wide range of concentrations. It is possible to determine one part of any element in a 100-fold excess of an other or others combined, and 0.5mg of any of the elements can be determined. with certainty.