Ferroin indicator solution Redox Indicator, Reag. Ph. Eur., E0 in sulfuric acid 1 mol/l = +1,06 volt

Potassium carbonate,reagent grade, >=98%, powder, -325 mesh

Potassium carbonate,reagent grade, >=98%, powder, -325 mesh

Potassium chromate solution Volumetric, <FRAC Type=regular>1/30</FRAC> M K2CrO4 (0.1N)

Potassium dichromate solution Volumetric, <FRAC Type=regular>1/60</FRAC> M K2Cr2O7 (0.1N)

Sand, white quartz,purum p.a., powder

Sand, white quartz,purum p.a., powder

Ammonium hydroxide solution,28% NH3 in H2O, >=99.99% trace metals basis

Sodium phosphate dibasic,puriss. p.a., ACS reagent, anhydrous, >=99.0% (T)

Aldrich® flat-bottom flask capacity 500 mL, joint: ST/NS 24/40

Aldrich® flat-bottom flask capacity 1,000 mL, joint: ST/NS 24/40

Sulfuric acid concentratefor 1L standard solution, 0.05 M H2SO4 (0.1N)