According to AOCS CD 8b (Peroxide Value Acetic Acid-Isooctane Method); ISO (Animal and vegetable fats and oils. SAMPLING AND ANALYSIS OF COMMERCIAL FATS AND OILS AOCS Official Method Cd 8b Revised Peroxide Value Acetic. AOCS has standardized a method for. PV determination with chloroform (Cd. 8- 53) and with isooctane (Cd 8b). The latter method uses a mixture of acetic.
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The test should be carried out in diffuse daylight or in artificial light shielded from a direct light source References, 4. Fresh indicator must be prepared when the end point of the titration from blue to colorless fails to be sharp. The substances are generally assumed to be peroxides or other similar products of fat oxidation.
Do not reheat for filtration unless absolutely necessary. Add, while stirring, to mL of boiling water and boil for a few seconds. Titrate with sodium thiosulfate solution, shaking continuously until yellow color has almost disappeared. Allow dc stand for 5 min and then add mL of distilled water. Swirl to dissolve the sample.
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The TLV in air is 10 ppm. If a blue color is formed that requires more than 1 drop of 0. Continue the titration until the yellow iodine color has almost disappeared. This solution may be prepared by accurately pipetting mL of 0. When completely melted, remove the sample from the hot plate or oven and allow to settle in a warm place until the aqueous portion and most of the milk solids have settled to the bottom.
It is a strong oxidizing agent and a dangerous fire risk when in contact with organic chemicals.
AOCS CD 8b – 90 Peroxido
The TLV is 10 ppm in air. Cluster analysis of all factors showed that the oils fell into two groups: Rapid mechanical stirring e. Proceed as directed in Procedure for Fats and Oils, paragraphs 1—4. We need your help! Prolonged inhalation or ingestion can lead to liver and kidney damage and may be fatal.
The isooctane method is preferred due to the elimination of chloroform. A fume hood should be used at all times when using chloroform. The values presented may not be applicable to matrices other c those presented and may not be representative for other concentrations. Isooctane has been proposed as a replacement for chloroform in this method.
Size px x x x x The results are presented in ISO When completely melted, remove the sample from the hot plate or oven and allow to settle in a warm place until the aqueous portion and most of the milk solids b8 settled to the bottom.
AOCS CD 8b – 90 Peroxido – Free Download PDF
A properly operating fume hood should be used when working with this solvent. It is toxic by ingestion and inhalation. If the titration is less than 0. Immediately remove from heat and cool. Continue the titration until the yellow iodine color has almost disappeared. Erratic results reported for this method, especially at higher peroxide values, appear to be related to the isooctane floating on the surface of the aqueous layer References, 3. Please help us to share our service with your friends.
The TLV in air is 10 ppm. Make certain the solution remains saturated during use, as indicated by the presence of undissolved KI crystals. Avoid contact with the skin.
The International Standards Organization ISO successfully completed an international collaborative study of this method in Sodium thiosulfate solution, 0. Decant the oil into a clean beaker and filter through a Whatman no. Many unconventional edible plant oils are available on the market, but their quality and composition are often unknown. Explosive limits in air are 1. Oil and Soap 9: Fresh indicator must be prepared when the end point of the titration from blue to colorless fails to be sharp.
Add 1—2 mL of starch indicator and continue the titration, adding the thiosulfate solution slowly until the blue color just disappears.
Potassium iodide KI solution—saturated, prepared fresh each day analysis is performed by dissolving an excess of KI in recently boiled distilled water about Page 2 of 2.
Starch indicator solution—tested for sensitivity, prepared by making a paste with 1 g of cc see Notes, 2 and a small amount of cold distilled water.