Sulfur-containing compounds, such as sulfur dioxide and sulfites, are widely used as preservatives and anti-oxidants in foods and beverages. Exposure to high levels of sulfites can cause an allergic reaction, difficulty breathing, sneezing, throat swelling, hives and migraine headaches. Given the health risks associated with sulfite exposure, the amount of sulfites in beverages and foodstuffs is regulated in many countries. Regulations can set the maximum amount of sulfites used and require labels to indicate the presence of sulfites. Numerous methods are used to determine sulfite concentration. The methods, however, are disadvantageous for various reasons. Disadvantages include the complexity of the methodology, the large amount of time involved, the inaccuracy of results, the use of toxic chemicals, inconvenience, and the required use of special equipment. A method that overcomes these disadvantages is desirable. The method described herein is simple and fast using the Distillation Unit K-355 or the KjelFlex K-360. The results are accurate, repeatable, and reproducible. The results also compare favorably to results obtained with methods employed by regulatory agencies. In addition, the use of toxic chemicals, such as lead, is avoided. Furthermore, the method is economically and conveniently carried out using reagents commonly found in laboratories.