all adjuncts in liquid form
Spectrophotometric color determination of a previously diluted sample (10 % solution, refer to R-160.01.005 Extraktgehalt von flüssigen Malzersatzstoffen).
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
After extraction with toluene, the α-acids and β-acids in the hops and hop pellets are determined using spectrophotometry.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The nickel content is determined by employing a flameless method which utilizes graphite furnace atomic absorption spectrophotometry. This technique is suitable for determining the nickel content of water with very little nickel contamination. Any matrix effects can be eliminated by using the standard additions calibration technique.
An aliquot of the sample is dosed into a graphite tube and is subsequently subjected to a program comprising a three-step temperature regime through electrothermic resistance heating. As the temperature increases in each step, the consecutive steps include drying, matrix pyrolysis (incineration) and thermal dissociation into free atoms (atomization). These can be carried out separately. During the analysis, the graphite tube is under an inert gas atmosphere (argon).
Also important for graphite furnace AAS is background correction, which can be achieved using a continuum radiation source (deuterium) or through the Zeemann effect. Background correction with the Zeemann effect is used for particularly difficult sample matrices.
A hollow-cathode lamp usually serves as the light source.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The hydride technique is used to determine the concentration of selenium ions in the water sample. In this process, selenium ions are reduced by sodium tetrahydroborate in an acidic medium. This compound is then transferred using an inert gas into a heated quartz cuvette, where it is pyrolyzed and measured using AAS.
Bestimmung des Eisengehalts mittels Spektralphotometrie
Suitable for all types of wort, beer and beer-based beverages
Zweiwertiges Eisen bildet mit dem Dinatriumsalz von 5,6-Diphenyl-3-(2- pyridyl)-1,2,4-triazin-4,4’-disulfonsäure (Ferrozin) einen violett gefärbten Komplex mit einem sehr hohen molaren Extinktionskoeffizienten. Dreiwertiges Eisen muss vor der Bestimmung zu zweiwertigem mit Hilfe von Ascorbinsäure reduziert werden. Die Farbintensität des gebildeten Komplexes misst man spektralphotometrisch [1, 2].
Determination of the nickel content by means of spectrophotometry
Suitable for all types of wort, beer and beer-based beverages
After digestion of the sample, a complex is formed with dimethylglyoxime which is then measured photometrically.
