Titrimetric determination of sulfate

Photometry

Article	Name
AB-140	Titrimetric determination of sulfate
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!
AB-094	Potentiometric and photometric analysis of honey
Simple methods are described for the analysis of honey that permit any damage or adulteration to be detected. The pH and total acids are determined together with the lactone and formol numbers. The determination of the hydroxymethylfurfurol content (HMF) is carried out photometrically. A separate method exists for the determination of water by the Karl Fischer method.
AB-093	Potentiometric analysis of cadmium plating baths
This Bulletin describes titrimetric methods for the determination of cadmium, free sodium hydroxide, sodium carbonate and total cyanide. The free cyanide can be calculated from the total cyanide and the Cd content.
AB-063	Determination of silicon, calcium, magnesium, iron and aluminum in cements by photometric titration of the solubilized product
The insoluble silicon dioxide remaining after dissolution of cement is determined gravimetrically. The calcium, magnesium, iron and aluminium in the filtrate are determined by photometric EDTA (0.1 mol/L) titration using a 662 Photometer. The following instructions conform to the analytical methods of 11 November 1981 recommended by the Association of Austrian Cement Manufacturers.
AB-049	Colorimetric determination of copper
Application Bulletin no. 43 describes the polarographic determination of copper. For copper concentrations of 10 mg/L and below, however, colorimetric methods are also used, particularly in water analysis. The method using sodium diethyldithiocarbamate can be employed down to a minimum limit of 0.01 mg/L Cu, but suffers from the drawback that the determination can also be affected by other metal ions. The method using neocuproine has a minimum concentration limit of 0.1 mg/L Cu, but has the advantage of being unaffected by ions of other metals.
AB-033	Determination of the total, calcium and magnesium hardness of water samples by photometric titration
This Bulletin describes the determination of the total, calcium and magnesium hardness of water using the light-guide photometer and/or Spectrode.
AB-030	Photometric determination of chromium(VI)
With chromates and dichromates, diphenylcarbazide gives a red-violet coloration which can be measured with the 662 Photometer. The reaction is extremely sensitive, enabling concentrations of ρ(Cr) <> In electroplating effluents, chromium occurs as the Cr(VI) ion. It must first be reduced to Cr(III) and then precipitated as the hydroxide. With incomplete reduction, hexavalent chromium remains in solution in the effluent water. For this reason, periodic checks for chromium in the effluent are necessary.
AB-029	Determination of chlorine in water with the 662 Photometer
The well-known method for determining free chlorine in water with o-tolidine is described and the absorbance coefficients determined for the 662 Photometer are given.