Storage of Reagents for Chlorine Dioxide Testing

Proper storage of reagents used for chlorine dioxide (ClO₂) determination is critical to ensure accuracy and safety. Common reagents include DPD (N,N-diethyl-p-phenylenediamine), potassium iodide (KI), buffers, and acid solutions. Follow these guidelines:

Light Protection – Many reagents, especially DPD, are photosensitive. Store them in amber glass bottles or opaque containers, away from direct sunlight.

Temperature Control – Keep reagents in a cool (2–8 °C recommended for some), dry place. Avoid freezing or exposure to high heat, which can degrade active ingredients.

Airtight Sealing – ClO₂ reagents are often hygroscopic or reactive with air (e.g., KI oxidizes easily). Seal containers tightly after use. Desiccants may be added if necessary.

Separation from Interferents – Store away from reducing agents, organic matter, strong acids/bases, and chlorine-based compounds to prevent cross-contamination or premature reactions.

Expiry Monitoring – Label each reagent with preparation/receipt date and expiry. Discard discolored or clumped reagents, as they may yield false readings.

Safe Handling – For liquid reagents, use non-reactive caps (e.g., PTFE-lined). Always follow the manufacturer’s SDS for specific hazards and incompatibilities.

By adhering to these storage practices, laboratories can maintain reagent integrity and obtain reliable chlorine dioxide measurements.