This method describes the conditions under which sensory analysis should be carried out.
beer, beer-based beverages, non-alcoholic beverages, mineral water
The basic prerequisites for properly conducting sensory analysis include assigning random numbers to samples which can later be referenced correctly to the results as well as employing the correct pouring technique when pouring the samples into the tasting glasses.
This method describes the determination of the chemical oxygen demand in wastewater photometrically with a cuvette test.
Oxidizable substances in the water sample react with the sulfuric acid potassium dichromate solution in the presence of silver sulfate as a catalyst. Chloride is masked with mercury sulfate. The decrease in the yellow color of Cr6+ is measured.
This method describes how to determine the chemical oxygen demand in wastewater through oxidation with potassium dichromate.
Potassium dichromate is added to the acidified sample as an oxidizing agent along with silver sulfate as a catalyst; mercury sulfate is also added to prevent the formation of elemental chlorine from chlorides. After oxidation of the organic substances in the sample (the dichromate ion is reduced to the chromium(III) ion in an acidic solution), the chromate required to achieve this is determined through reverse titration of the excess potassium dichromate with iron(II) solution (adjusted) against ferroin as an indicator [1].
Cr2O72- + 6 e- + 14 H3O+ → 2 Cr3+ + 21 H2O
Cr2O72- + 6 Fe2+ + 14 H3O+ → 2 Cr3+ + 6 Fe3+ + 21 H2O