Minerals and trace elements (e.g., K, Ca, Na, Mg, Fe, Cu, Zn, Mn) play a significant role in beer production and in product quality.
This group of elements is important, e.g., for yeast growth, and therefore for fermentation. However, if concentrations are too high, particularly of heavy metals, this may have very adverse effects on the stability and sensory properties of the beer. For this reason, mineral analysis may be helpful when problems arise. Elements such as potassium and magnesium are also important for human nutrition. Typical analysis techniques such as gravimetry, complexometry and colorimetry are either too imprecise or involve complex procedures and are very time-consuming. Atomic absorption spectrophotometry or atomic emission spectrometry with inductively coupled plasma (ICP-AES or ICP-OES) represent an elegant, rapid and very precise analysis technique.
Generally speaking, the following methods are suitable for use with Congress wort samples.
Atomic Absorption Spectrophotometry (AAS) is based on the phenomenon of resonance absorption.
An element-specific light source (e.g. hollow cathode lamp or gas emitting lamp) radiates through a space (e.g. flame or absorption cuvette) containing the absorption medium, namely the metal of the element to be measured, in a vaporized form. This method is based on the fact that radiant energy causes the excitation of atoms from their base orbitals, which then absorb specific frequencies of light, resulting in characteristic spectra. The reduction in the resonance energy is proportional to the concentration of the element present and is separated from the other frequency lines originating from the light source by a monochromator. These are then further transformed by a detector to an electrical signal, which is displayed digitally or recorded.
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