Minititrator Reagents 

The HI84500-61 alkaline reagent is necessary for the analysis of total sulfur dioxide. The alkaline reagent raises the pH and liberates bound sulfur dioxide. This pH adjustment ensures that all of the free and bound sulfur dioxide is accounted for to give an accurate measurement of total sulfur dioxide. The HI3148B ORP electrode is used to detect the endpoint for both the low (1.0 to 40.0 ppm of SO2) and high (30 to 400 ppm of SO2) ranges. The HI84500 can be used with all wines, including red, which are difficult to test using traditional methods due to the difficulty to observe a distinctive color change when the endpoint is reached.

The HI84500 determines the free and total sulfur dioxide concentration in wine using the Ripper method. Excess iodide is added to the wine sample and reacts with the iodate titrant to produce iodine:

IO₃^- + 5I^- + 6H⁺ → 3I₂ + 3H₂O

The iodine produced reacts with sulfur dioxide in the wine according to the redox reaction below:

H₂SO₃ + I₂ → H₂SO₄ + 2HI