The flame-spectroscopic determination of sulphur and phosphorus in organic and aqueous matrices by using a simple filter photometer

Abstract

A sensitive and selective chemiluminescent molecular-emission method for the determination of sulphur and phosphorus is described, based on passing the test solutions into a cool reducing, nitrogen-hydrogen diffusion flame. The resulting band emission at about 394 nm for sulphur and 520 nm for phosphorus is measured on a simple filter photometer. The limits of detection in aqueous solution by using conventional nebulising techniques with a heated chamber are 0·08 p.p.m. for sulphur and 0·007 p.p.m. for phosphorus.Most cations interfere by producing depressive matrix effects, but these can be overcome by a preliminary “batch” ion-exchange separation.For the determination of sulphur or phosphorus in organic matrices, the test solutions can conveniently be prepared by oxygen-flask combustion techniques. In a few instances it is possible to inject directly both aqueous and organic solutions into the flame.The method has been applied to the determination of sulphur in light distillates.