Free sulfur dioxide (Free SO2) in Wine
Sulfur dioxide (SO2) is used in oenology mainly as preservative, but also for other purposes (for example for antiseptic, antioxidant, antioxidasic, solubilizing, combining and clarifying functions). Part of the SO2 that is added as potassium metabisulfite to musts and wines undergoes a series of reactions. Therefore, after a short period of time, most of the sulfur dioxide reacts with some of the substances present, binds with them and forms addition compounds (combined sulfur dioxide) that are unable to express the typical properties of unbound molecules. Therefore, only the part that does not combine (free sulfur dioxide) plays an important role in preserving wine from oxidizing alterations and from some micro-organisms. This test can be used to determine the fraction of free SO2 .
Instruments to Use
WineLab is simple and reliable system to perform wine analysis.
The system is supplied pre-calibrated and ready for use.
Results are expressed in accordance with the reference method.
It is also possible to standardize the system using samples with a known titration.
Reagents
Code *300345 – The kit, designed for 10 tests, comprises:
- R1: package with 10 pre-vialed test tubes containing 1 ml of acid phosphate buffer
- R2: bottle containing a pH 7.5 solution of an organic disulphide
Test principle
The free fraction of sulfur dioxide is made to react with an organic disulphide in order to form a colored compound, whose intensity, measured at 420 nm in kinetics, is directly proportional to the concentration of free sulfur dioxide in the sample.
Sample
Wine as is.
Compliance with reference method
The calibration curve of wineLab, obtained using reference methods, confirms the excellent linearity of the system over the whole testing range.
Using WineLab you can also perform
- Volatile Acidity (Acetic acid)
- Total sulfur dioxide (Total SO2)
- Malic acid
- Lactic acid
- Alcohol
- Reducing sugars (glucose and fructose) in wine and must
- Anthocyanins in wine and must
- Polyphenols
- Colour intensity and tonality
| Reagent developed by CDR s.r.l | ||||
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Quality System certified ISO 9001 Ed. 2008 |
