Technical data sheet
Moisture by Karl Fischer is determined by automated potentiometric titration with an iodine and sulfur dioxide reagent. Moisture is extracted into an appropriate solvent and is titrated volumetrically (as opposed to colorimetric titration). This method is applicable to high-fat samples or samples that contain compounds that may volatilize when heated or subjected to vacuum (e.g. alcohol, glycerine, etc.)
Alcohol, butter, extracts, ethanol, fats, fish feed, flavorings and enhancers, glycerin, liqueur, margarine, mayonnaise, mineral oil, mouthwash, niacinamide, oils, pet food, propylene glycol, raisins w/ glycerin, shortening, solvents and sterols.
Any matrices not listed above as acceptable.
Standard titration set up.
AOAC 984.20, 967.19, 977.10 and AOCS Ca 2e-55.
Sample size requirements
Information required by submitter
Please supply expected estimates for each sample. As complete a description as possible is requested as some compounds will interfere with the Karl Fischer titration (e.g. antioxidants, oxidizing or reducing agents, strong acids, strong bases) or may require special handling in order to extract all water (e.g. dried fruits, fruit leathers, some specialty carbohydrates).
Moisture in most food materials can be determined by loss on drying using a Gravimetric Moisture method. For samples high in fat or that contain components that will volatilize under the conditions of the Gravimetric Moisture assays, the Karl Fischer titration may be more appropriate.
Note that chemically bound water molecules may be incompletely detected by this method.