Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . c. por- xxin] FATS AND OILS 309 tions of neutral 90% alcohol by volume through the filter, each portion previouslypassed through the condenser, the 25 cc. cylinder and the 110 cc. receiving the combined alcoholic washings with N/10 sodium hydroxid, using phenol-phthalein as an indicator. Run a blank in the same manner and subtract the quantity of the standard alkalirequired to neutralize the 45 cc. of alcohol, used in washing the apparatus and filterpa
Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . c. por- xxin] FATS AND OILS 309 tions of neutral 90% alcohol by volume through the filter, each portion previouslypassed through the condenser, the 25 cc. cylinder and the 110 cc. receiving the combined alcoholic washings with N/10 sodium hydroxid, using phenol-phthalein as an indicator. Run a blank in the same manner and subtract the quantity of the standard alkalirequired to neutralize the 45 cc. of alcohol, used in washing the apparatus and filterpaper of the blank, from that required in each Polenske determination. Reportthe Polenske number as the number of cc. of N/10 alkali required to neutralize theinsoluble volatile acids from the 110 cc. of distillate as obtained above. Since theentire distillate is filtered it is not necessaiy to multiply the burette reading by ,as in 25, but a calculation must be made, as directed in 25, to reduce the actualnumber of cc. found in the titration to the number which would have been requiredhad exactly 5 grams of fat been FIG. 13. APPARATUS^ FOR THE DETERMINATION OF THE POLENSKE AND SOLID FATTY Muter Method, Modified by Lane^.—Tentative. Weigh 5 grams of the oil or fat into an Erlenmeyer flask, saponify, precipitate withlead acetate solution and treat the precipitated lead soap with ether, as directedunder 37. Filter the ether solution of the soluble lead soap into a Muter tube orseparatory funnel and decompose the soap by shaking with 40 cc. of hydrochloricacid (1 to 5). The soap is completely decomposed when the ether becomes clearand colorless. Draw off the lead chlorid from the ether solution and wash the ether free fromacid. Evaporate, until free from ether, an aliquot of this solution in an atmosphereof carbon dioxid, in order to prevent the oxidation of the oleic acid, and weigh todetermine the per cent of liquid acids; determine the iodin num
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