Iodine value of vegetable oils without wijs solution icl. Pdf fast determination of iodine number of biodiesel using. The reagent is an unstable one and the concentration of the reactant changes with time. Halogens add quantitatively to the double bonds in the unsaturated fatty acids, principally oleic and linoleic acids in the case of corn oil.
For the determination of the iodine number of oleic and ricin oleic acids both the hanus and the rosenmund methods give the same value which is very near the theoretical. Of the methods now reproduced in this 1st supplement, 15 have already been published in pure and applied chemistry. Use quotes to search for a method number cd 2393 or an exact phrase olive oil. One of the most commonly used methods for determining the iodine value of lipids is wijs method. The lipid to be analyzed is weighed and dissolved in a suitable organic solvent, to which a known excess of iodine chloride is added. Convenient method is to reserve some of original i solution, add slight excess of cl to bulk of solution, and bring to desired titer by readditions of reserved portion. Various factors affecting results, and possible sources of error, were investigated. The iodine value in chemistry is the mass of iodine in grams that is consumed by 100 grams of. Normally, iodine is absorbed quite slowly but this method makes use of wijs, which is a stable solution consisting of iodine monochloride icl in acetic acid that reduces absorption time to approximately half an hour. Redox titration by automatic potentiometric titrator. Iodine value of edible oils and fats according to wijs aoac method 1 dissolve the sample in ccl 4, add 25 ml wijs solution and keep in the dark for approx. Iv is a measure of the number of double bonds in the unsaturated fatty acids in one gram of oil.
Two collaborative studies were conducted using the wijs method for determining the iodine value in a wide range of vegetable. The method is based on the quantitative determination of fatty acid methyl esters of vegetable oils by capillary gas chromatography. New sections containing methods for lecithins and emulsifiers are now included. Wijs method definition of wijs method by merriamwebster. Since the publication of the 7th edition of the standard methods, the commission has developed and adopted more than 20 new methods. If the iodine number is to be characteristic of the oil, the sample should be substantially free of moisture and foreign materials. Da 1548 iodine value, soap and soap products, wijs method da 1648 saponification value of soap and soap products da 1752 borax in soap and soap products. The most common methods used for iodine value determination are the wijs and. Pdf a simple titrimetric method for the determination of the iodine value of vegetable oils is proposed. Food and drug administration, division of pesticide and industrial chemicals, washington, dc 20204. A new calculation method for the determination of iodine value iv from measurements of fatty acid methyl esters is proposed.
Further the method is sensitive to moisture, sunlight etc. The acid value is a measure of the amount of free acids present. It may be determined by any of the following methods. Wait for the conversion process to finish and download files either separately, using thumbnails, or grouped in a. Addition of iodine chloride and backtitration with sodium thiosulphate by din 532411. Use clear sediment free liquid directly after inverting container several times. Try the highest quality compress pdf online tool for free, and see how easy it is to reduce the file size of your large pdf files. By carrying out a blant we are trying to eliminate the errors that can come due to these factors. Nutrition laboratory report nt20903 food chemistry and biochemistry determination of free fatty acidffa and iodine value ivin oil lecturer name. The i value iv of palm oil and fractions olein, stearin were determined by wijs method. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Find and purchase methods from the official methods and recommended practices of the aocs. Aocs cd 125 iodine value of fats and oils wijs method free download as pdf file. Click the upload files button and select up to 20 djvu files you wish to convert.
This standard is issued under the fixed designation d 5554. The test sample is made out of bio diesel fuel dissolved in cyclohexane, added in excess with wijs reagent 0. Pdf standard test method for determination of the iodine. Standard methods for the analysis of oils, fats and. Use this free online djvu to pdf converter to convert djvu files to adobe pdf documents, quickly and easily, without having to install any software. The iodine monochloride halogenates the double bonds in the fat, and the residual icl is reduced to free iodine in the presence of. Connectedpdf is leading edge technology that powers cloudbased services for pdf. Rearrange individual pages or entire files in the desired order. Wijs titrimetry i named animal fats peroxide value aocs cd 8b90 97. A new rapid titration method for determining the halogen ratio of wijs. Hoffman and green modified the wijs method by employing mercuric acetate as catalyst and made it possible to determine the iodine value of a sample in ten minutes or so. Introduction the iodine value of animal and vegetable fats and oils measures the amount of cc double bonds present in the product. The higher the iodine value, the more unsaturated fatty acid bonds are present in a fat.
The wijs method involves the addition of a solution of iodine monochloride in a mixture of acetic acid and cyclohexane to a test sample. Change text and images quickly and easily in pdf documents. Modified kjeldahl method aa 638 free fatty acids in cottonseed. Authors have investigated other methods of quick determination of iodine value especially for the oils in the hydrogenation process and have found after all the wijs method could be appropriate by only shortening the reaction time to three minutes for the oils of the iodine value less than about 100. In linoleic acid and cod liver oil the hanus method gives 2 to 4 per cent higher values than the other. Determination of free fatty acid ffa in oil and determination of iodine value iv in oil introduction acid value or free.
The procedure is applicable to fats and oils from corn, grain sorghum and other vegetable sources, which. In lieu of an abstract, this is the articles first page. Individual methods purchased online are delivered as a downloadable pdf. Foxit reader goes beyond a pdf viewer, its connectedpdf powered. The free iodine in wijs solution is titrated directly, in strong.
Method a iodine monochloride method or wijs method. Learn how to edit pdf files using adobe acrobat dc. In this procedure, the biodiesel sample reacts with wijs solution in the presence of a. Moisture content of oils and fats is the loss in mass of the sample on heating. Aocs cd 125 iodine value of fats and oils wijs method scribd. How to electronically sign pdf documents without printing. You can then edit the word document, extract its contents and republish in pdf as a new document. The vegetable oil sample is reacted with an excess of iodine monochloride solution wijs reagent under controlled conditions. A green potentiometric method for the determination of the. Mercuric acetate, however, cannot be empolyed now because the reaction solution is hard to meet the regulation of water pollution and its disposal has become difficult. Searches can be performed by method number, keyword, analyte, industry, method title, or compound. The result is expressed as g of iodine i2 per 100 g of sample. The method is applicable to the determination of free.
Analytical method for determining the degree of unsaturation of a material, which involves the addition of iodine to the existing double bonds. Compress a pdf file online for free adobe acrobatus. Wi the files are in electronic format pdf docdocx and will be sent to your email within 24 hours. On the determination of iodine value by the wijs method. An aliquot of the sample was weighed according to the expected iodine number.
The free iodine in wijs solution is titrated directly, in strong hydrochloric acid solution, with standard potassium iodate solution. Sources of errors in the determination of iodine value of. The free iodine in wijs solution is titrated directly, in strong hydroehlorie acid solution, with standard potassium iodate solution. Jis k 00701992 test method for acid value, saponification number, ester number, iodine number, hydroxyl value of chemical products and unsaponifiable matter. This unsaturation is in the form of double bonds which react with iodine compounds. The chemical reaction associated with this method of analysis involves formation of. This dissertation is brought to you for free and open access by the iowa state university capstones. Then to this mixture potassium iodide is added which reacts with remaining free iodine chloride to form potassium chloride. Pdf a new and fast method was developed to determine the iodine number of. The wijs method, the wijs potentiometric method this paper, the visual method and the potentiometric method proposed in this paper were all applied.
After iodine addition to the double bonds has occurred, the excess iodine monochloride is reduced to free iodine by addition of potassium iodide solution and water. Iodine value of edible oils and fats according to wijs. Use clear sedimentfree liquid sample directly after inverting the container several. Preserve the pdf files fonts, paragraphs, lists, tables, and columns in the word output. Chocolate and chocolate products fat free cocoa solids aoac 931. Standard test method for determination of iodine value of. Convert your pdf file into editable word documents with the best pdf to word converter. The iodine value is the number which expresses in grams the quantity of halogen, calculated as iodine, which is absorbed by 100 g of the substance under the described conditions. Pdf a simple, fast, and green titrimetric method for the. Determination of the iodine value of oils and fats. A critical study of the precision and value of halogen addition.
641 535 113 268 1550 187 962 58 207 161 549 1275 1473 1188 545 157 246 1547 398 490 865 1407 1431 21 1000 713 1014 1481 741 879 1609 850 1482 1317 941 1259 1086 702 301 403 1475 1179 376 1480 395 1437 263 613