Determination of sulfates in drinking water

Sulfates in drinking water in the concentration range 20 mu M to 20 mM are conductometrically titrated with the titrant Ba(OAc)(2) in the presence of ethanol. The titrations are performed in an automatic mode with monotonic a ddition (constant flow rate) of titrant. The titrations are preceded by a f low pretreatment of the samples, in which the interfering species Ca2+, Mg2 +, and bicarbonates are removed. The pretreatment apparatus consists of two cation-exchange columns with conductometric probes at their exits and a th in-layer degassing device for removal of CO2. The advantages of tungsten in a two-electrode conductometric cell are demonstrated. (C) 1999 Academic Pr ess.