Used in analytical chemistry for the determination of sulfite content in various samples, such as water, food, and beverages. Commonly employed in titration methods, including iodometric titrations, to quantify reducing agents. Essential in environmental testing to monitor sulfite levels in wastewater and drinking water. Also utilized in the food and beverage industry to ensure compliance with regulatory limits on sulfite additives, which are used as preservatives but can cause allergic reactions in sensitive individuals. Provides a reliable reference for calibrating instruments and validating test methods.