Sulfur dioxide determination

Sulfur dioxide (SO₂) is a colorless, pungent, and reactive gas that has long been used as a food additive and preservative. Its antimicrobial and antioxidant properties make it widely used in the food industry, particularly in the preservation of wine, dried fruits, and fruit juices. However, due to its potentially adverse health effects, its concentration in consumer products must be strictly controlled.

Sulfur dioxide measurement is essential for verifying food compliance with the maximum permitted limits set by European and international regulations. It is also crucial in the environmental sector for monitoring industrial emissions and air quality.

Analytical principle

Several analytical approaches are used to determine the sulfur dioxide concentration according to the matrix:

• Iodometry : classic titration method based on the oxidation of sulfur dioxide, used in oenology and the food industry.
• Distillation followed by dosage : reference method in certain laboratories for isolating free and total SO₂.
• Enzymatic methods : rapid and specific alternatives, adapted to food matrices.
• GC-MS (gas chromatography coupled with mass spectrometry) : used for precise and sensitive analyses, particularly in complex matrices or in the environment.

These techniques guarantee reliable and reproducible results, adapted to traceability and regulatory compliance requirements.

Industrial applications

Sulfur dioxide measurement applies to many areas:

• Food industry : control of SO₂ levels in wines, beers, juices, dried fruits, jams, sauces and processed products.
• Nutraceuticals : securing herbal ingredients and food supplements.
• Oenology : precise monitoring of free and total SO₂ levels in wines to ensure their microbiological and organoleptic stability.
• Environment : measurement of sulfur dioxide emissions into ambient air and industrial effluents, as part of atmospheric pollution monitoring.

Affected matrices

The most frequently analyzed matrices include:

• Wines and fermented beverages
• Dried fruits (apricots, raisins, figs)
• Fruit juices and nectars
• Jams, sauces and canned food
• Dietary supplements and herbal formulations
• Air samples and industrial emissions
• Water and effluents contaminated by SO₂

Quality and regulatory issues

Sulfur dioxide control addresses several major challenges:

• Regulatory compliance : compliance with maximum limits set by the European Union, the Codex Alimentarius and international standards.
• Consumer protection : prevention of adverse reactions, particularly in people with asthma or sensitivity to sulfites.
• Organoleptic quality : control of concentrations in wine and food products to preserve taste, color and stability.
• Environmental monitoring : monitoring of industrial atmospheric emissions, in line with the European directive on air quality.

YesWeLab support

YesWeLab offers comprehensive support for sulfur dioxide measurement through its network of certified and accredited partner laboratories (ISO 17025, COFRAC). We provide:

• A selection of the most suitable methods (iodometry, GC-MS, distillation, enzymatic) depending on your matrices.
• Scientific expertise to interpret the results and ensure their compliance.
• An intuitive digital platform for managing your samples, tracking them in real time and receiving results quickly.
• Reliable and reproducible analyses, meeting national and international standards.