Turbidimetric determination of sulphate in waters employing flow injection and lead sulphate formation

Abstract

An analytical flow-injection procedure based on PbSO 4 colloidal formation is proposed as a turbidimetric determination of sulphate in natural waters. Ethanol-water was used as a medium in order to improve the sensibility of the method. Both chemical and flow variables as well as interfering species were studied. A detection limit of 0.3 μg SO 2− 4 ml −1 was found, and the analytical range (according to Beer's law) was 2–20 μg SO 2− 4 ml −1. The precision was better than 3% R.S.D. and the sample throughput was ca. 35 h −1. The method, when compared with a standard methodology, gave good results when applied to water analysis.