Boiler feed water for use in the production of beer and other foods
Copper forms a complex with sodium diethyldithiocarbamate with a maximum absorption at 436 nm.
If the copper content is high, turbidity will result. In such cases, the water sample must be diluted. The method is suitable for water with a copper content up to 1 mg/l. An extraction must be performed in order to determine extremely low concentrations of copper.
This method describes how to measure the surface tension of wastewater using a tensiometer.
Wastewater generated in the industrial production of beer and food
The force measured in this analysis is exerted by the surface tension. The surface tension can be measured either as the force on a plate oriented perpendicular to the surface of the liquid and thoroughly wetted by it (static method) or the force that is required in order to pull out a horizontally suspended rod or ring from the liquid surface (quasi-static method).
Enrichment of the PAH is performed using solid phase extraction. The extract is obtained from the sample through separation with high performance liquid chromatography on the appropriate stationary phases under isocratic conditions. Detection is conducted with a fluorescence detector. The determination is quite sensitive because these polycyclic aromatic hydrocarbons possess substantial fluorescence properties. Since the fluorescence characteristics of these substances are substance-specific, they are determined using two spectra, the excitation and emission spectra. Thus, selective detection is possible. Through recognition of the specific spectra for each substance and the means of detection at the appropriate wavelengths, maximum sensitivity and selectivity are attainable.
The PAH compounds are concentrated through extraction with cyclohexane and evaporation. The separation is carried out by means of high-performance thin-layer chromatography. The results are evaluated through examination under UV light, followed by comparison of the Rf values with the reference substances.
This method describes how to determine the iron content of boiler feed water. Iron can cause surface deposits to develop.
Boiler feed water for use in the production of beer and other foods
Fe(III) ions form a complex with sulfosalicylic acid, which is red in an acidic solution and yellow in an alkaline solution. Since Fe(II) ions are oxidized in an alkaline solution, they are detected as well. In this way, the value for total iron can be measured.