WIJS REAGENT

Product Name: Wijs Reagent
Common Name: Wijs Solution / Iodine Monochloride Solution in Acetic Acid
Pack Size: 500 mL
Brand: WinLabs & Stores (WLS)

Description:
Wijs reagent is a halogenating reagent used primarily for iodine value determination in fats, oils, and biodiesel. It works by reacting iodine monochloride with carbon-carbon double bonds, allowing estimation of the degree of unsaturation. Modern commercial Wijs solutions are commonly supplied as iodine monochloride in glacial acetic acid, and some references specify about 0.1 mol/L ICl or approximately 0.22 N solution strength.

Key Use / Application:
Used in physicochemical analysis of oils and fats for iodine value (IV) determination, a standard index of unsaturation in edible oils, industrial oils, and biodiesel. AOAC recognizes the Wijs method for iodine value determination.

Typical Composition:
Iodine monochloride (ICl) — active halogenating component
Glacial acetic acid — solvent medium
Some SDS and supplier references list the mixture as predominantly acetic acid with a small proportion of iodine monochloride.

CAS / Component References:
Iodine monochloride: CAS 7790-99-0
Acetic acid (glacial): CAS 64-19-7
Comparable Supplier References:
Commercial Wijs reagent or equivalent iodine monochloride solutions are offered by MilliporeSigma, Fisher Chemical / Thermo Scientific, FUJIFILM Wako, Loba Chemie, Carl Roth, and SRL.

Typical Associated Reagents in the Test Method:
For iodine value determination, Wijs reagent is commonly used together with:
Potassium iodide (KI)
Sodium thiosulfate standard solution
Starch indicator
Suitable solvent system per method standard.

Handling:
Use in a fume hood or well-ventilated laboratory area. Avoid inhalation, skin contact, eye contact, and contamination with incompatible materials. Use appropriate PPE including gloves, goggles, and protective clothing. Supplier SDS documents classify Wijs-type iodine monochloride/acetic acid solutions as corrosive, and acetic-acid-containing formulations may also carry flammability concern.

Storage:
Store tightly closed in a dark amber glass bottle, protected from light, in a cool dry place. Multiple supplier references indicate storage around 15–25°C or cool-room conditions, away from heat and incompatible substances.

Hazard Information
Corrosive to skin and eyes
Contains strong acid medium
May be irritating to respiratory tract
May present flammability risk due to acetic acid content depending on concentration and classification
For professional laboratory use only.

Packaging:
500 mL amber reagent bottle
Tight cap closure
Laboratory / technical use packaging
Label Use Line Suggestion:
GRADE: Technical / Laboratory Reagent
USE: Iodine Value Determination.