This Bulletin describes three potentiometric and one photometric titration method for the determination of sulfate. Which indication method is the most suitable depends above all on the sample matrix and is illustrated with examples.
Method 1: Precipitation as barium sulfate and back-titration of the Ba2+ excess with EGTA. The ion-selective calcium electrode is used as indicator electrode.
Method 2: As in method 1, but with the electrode combination tungsten/platinum.
Method 3: Precipitation titration in semi-aqueous solution with lead perchlorate using the ion-selective lead electrode as indicator electrode.
Method 4: Photometric titration with barium perchlorate, thorin indicator, and the 662 Photometer or 525 nm Spectrode. Particularly suitable for micro determinations!