UV absorption of rectified alcohols of vitivinicultural origin (Type IV)
OIV-MA-BS-21 Absorbance test in UV light of neutral alcohol
Type IV method
- Purpose and scope
This method can be used to determine the optical permeability of neutral alcohol liable to enter into the composition of certain alcoholic beverages.
- Principle
The optical permeability of the sample in the wavelength range from 220 to 270 nm is measured against a defined reference substance with high optical permeability.
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Apparatus
- UV-visible spectrophotometer.
- Quartz cells 10 mm thick, with identical spectral transmission.
- Reagents
Hexane for spectroscopy.
- Procedure
- Rinse the tanks clean beforehand with a sample solution and then fill with the sample, dry the tanks outside,
- treat the reference cell (n) with hexane in the same way and fill it,
- determine the absorbance value and build the graph.
- Expression of results
The absorbance values recorded at 270, 240, 230 and 220 nm should not exceed the following values: 0.02, 0.08, 0.18 and 0.3. The absorbance curve must be smooth and regular.
- Bibliography
- Methods of analysis of neutral alcohol applicable in the wine sector. EEC Regulation No. 1238/92 (May 8, 1992), EEC Regulation No. 2009/92 (July 20, 1992).