Analytical Method
Quantitative technique used to determine the concentration of oxidizing agents by reacting them with iodide to produce iodine. Iodometric titration identifies the strength of chlorine or hydrogen peroxide in textile bleach liquors. It relies on the clear visual shift of a starch indicator to signal the end point of the reaction.
Chemical Sequence
Potassium iodide is added to the sample where it is oxidized to form molecular iodine in an acidic environment. Standardized sodium thiosulfate is then added until the blue-black color of the iodine-starch complex disappears completely. The volume of thiosulfate used directly corresponds to the original oxidant concentration.
Processing Utility
Regular use of iodometric titration ensures that pre-treatment baths remain effective without becoming overly aggressive. Variations in chemical levels lead to uneven whites or potential fabric damage if not monitored closely. Automated titrators increase the speed of these measurements in high-volume dyeing plants.
Equipment Maintenance
Fresh reagents are required because the accuracy of the iodometric titration depends on the precise normality of the sulfur solution. Starch indicators must be stored properly to avoid biological degradation that would obscure the visual signal. Verification of the standard against a primary reference maintains the integrity of the daily quality reports.
