TURBIDIMETRIC DETERMINATION OF SULFATE IN WATERS EMPLOYING FLOW-INJECTION AND LEAD SULFATE FORMATION

An analytical flow-injection procedure based on PbSO4 colloidal format ion is proposed as a turbidimetric determination of sulphate in natura l waters. Ethanol-water was used as a medium in order to improve the s ensibility of the method. Both chemical and flow variables as well as interfering species were studied. A detection limit of 0.3 mu g SO42- ml(-1) was found, and the analytical range (according to Beer's law) w as 2-20 mu g SO42- ml(-1). The precision was better than 3% R.S.D. and the sample throughput was ca. 35 h(-1). The method, when compared wit h a standard methodology, gave good results when applied to water anal ysis.