VWR Iodine trichloride (Wijs'reagent) for determination of iodine value

VWR Iodine Trichloride (Wijs’ Reagent) is a specialized reagent solution used for the determination of iodine value (IV) in fats, oils, and fatty acids, a critical measure of unsaturation. This reagent is a stabilized solution of iodine monochloride (ICl) or iodine trichloride (ICl₃) in glacial acetic acid, formulated to react quantitatively with the carbon-carbon double bonds present in unsaturated fatty acids.

The Wijs method, which uses this reagent, is a widely accepted standard protocol outlined by AOCS, ISO, and ASTM for determining the degree of unsaturation in edible and industrial oils.

Key Features

• High Reactivity: Ensures rapid and complete halogenation of double bonds in fatty acids.
• Stabilized Solution: Prepared in glacial acetic acid to maintain oxidative strength and shelf life.
• Analytical Grade: Suitable for routine laboratory determinations in food, cosmetic, and chemical industries.
• Conforms to Standard Methods: Compatible with ISO 3961, AOCS Cd 1-25, and ASTM D1959 methods for iodine value analysis.

Applications and Use Cases

1. Determination of Iodine Value (IV) in Oils and Fats

• Used to quantify the degree of unsaturation in:
  • Edible oils (olive, sunflower, soybean, etc.)
  • Animal fats and lards
  • Biodiesel and industrial oils
• Higher iodine value indicates more double bonds (higher unsaturation), which affects stability, shelf life, and reactivity.

2. Quality Control in Food and Cosmetic Manufacturing

• Helps assess oxidative stability and drying properties of raw materials.
• Used in formulation development and regulatory compliance testing.

3. Biodiesel Feedstock Analysis

• Assesses feedstock unsaturation which influences fuel performance.
• Important for monitoring compliance with biodiesel standards (e.g., EN 14214, ASTM D6751).

Standard Procedure (Simplified Wijs Method)

1. Sample Preparation
   • Dissolve a known weight (~0.2–0.5 g) of the fat or oil sample in chloroform or carbon tetrachloride in a glass-stoppered iodine flask.
2. Addition of Wijs Reagent
   • Add an excess of iodine trichloride solution (Wijs' reagent) to the sample under controlled conditions and mix well.
3. Reaction Time
   • Allow the mixture to stand in the dark at room temperature for 30–60 minutes (depending on the method and expected IV).
4. Titration
   • Add potassium iodide solution to release free iodine.
   • Titrate with standard sodium thiosulfate solution until the yellow color almost disappears.
   • Add starch indicator and continue titrating until the solution turns colorless.
5. Blank Correction
   • Perform a parallel blank determination (without the sample) to correct for reagent background.
6. Calculation
   • Calculate the iodine value (IV) using the difference between blank and sample titration volumes: 

Where:

• B = volume of thiosulfate for blank (mL)
• S = volume of thiosulfate for sample (mL)
• N = normality of thiosulfate solution
• 12.69 = constant derived from molecular weight of iodine

Safety and Handling

Always refer to the Safety Data Sheet (SDS) for full handling and disposal guidance.

Unique Advantages of VWR Iodine Trichloride (Wijs’ Reagent)

• Ready-to-use formulation saves preparation time and improves repeatability.
• Reliable performance in routine and regulated analytical settings.
• Compatible with multiple standard protocols, ensuring regulatory and methodological alignment.
• Available in multiple volumes to suit lab-scale or high-throughput environments.

For laboratory use only. Not for drug, food, or household use.