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

An analytical flow-injection procedure based on PbSO4 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 SO2−4 ml−1 was found, and the analytical range (according to Beerʹs law) was 2–20 μg SO2−4 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.