(1) That the following method for the determination of benzoic acid in almond extracts be adopted as tentative: Oxidation Method for Determining Benzaldehyde and Benzoic Acid Together. Measure 10 cc. of the extract into a 100 cc. flask, add 10 cc. of a 10% sodium hydroxid solution, and 20 cc. of U. S. P. hydrogen peroxid solution; cover with a watch glass and place in a water oven. Oxidation of the aldehyde to benzoic acid begins almost immediately and should be continued 5–10 minutes after all odor of benzaldehyde has disappeared, which usually requires 20-30 minutes. Remove the flask from the water oven, transfer the contents to a separatory funnel, rinsing off the watch glass, add 10 cc. of dilute sulphuric acid solution (1 to 5) and cool the contents of the funnel to room temperature under the water tap. Extract the benzoic acid with 4 portions of 25, 25, 20, and 20 cc. of ether, respectively, and wash the combined extracts with two portions of 5-10 cc. of water, or until all sulphuric acid is removed. Filter into a tared dish, evaporate at room temperature, dry overnight in a desiccator, and weigh the benzoic acid. Multiply the result by 10. Multiply the grams per 100 cc. of benzaldehyde obtained in the sample by 1.151 to obtain the equivalent of benzoic acid, and subtract this from the grams per 100 cc. of total benzaldehyde and benzoic acid obtained above. The difference will be grams of benzoic acid per 100 cc. of the extract. Approved. (2) That the Association of Official Agricultural Chemists, Methods, 1916, 265-9, be changed as follows: 35 (a), Phenylhydrazin solution. Line 2.-Eliminate the word "article" and substitute therefor the words "product in vacuo", making the sentence read: "A sufficiently pure product can be obtained by distilling the commercial product in vacuo, rejecting the first portions coming over which contain ammonia." 36, DETERMINATION. Line 1.-After the word "Weigh" insert the words "accurately about", making the clause read: "Weigh accurately about 15 grams of the sample into a small, glassstoppered flask;". 55, Hortvet and West Method Modified.—Tentative. Change the last sentence to read as follows: "Multiply the weight of salicylic acid so found by 9.33 to obtain the per cent by volume of methyl salicylate." Approved. (3) That Wichmann and Dean's qualitative method for coumarin in vanilla extract be studied with a view to its possible adoption as a preliminary test for the purpose of shortening the official method when coumarin is absent. The method is as follows: Make 10 cc. of extract alkaline with sufficient 10% sodium hydroxid solution, dilute with 15 cc. water, to reduce the alcoholic strength, and extract with 20 cc. of ether in a separatory funnel. The ether solution will be slightly colored when the brown lower layer has been drawn off. Add a few cc. of strong alcoholic potassium hydroxid solution and wash the mixture with 10 cc. of water. The ether layer will be white. This procedure removes all organic acids, coloring matter or saccharin that may be present. Place 1 cc. of 50% potassium hydroxid solution in a test tube and pour the ether solution of coumarin over it. After thoroughly shaking, hastily evaporate the ether. Then place the tube over a free flame and evaporate the water and fuse the potassium hydroxid. If coumarin is present in any amount, a change of color will be noticed as the evaporation of the water proceeds and fusion begins. Even very small quantities of coumarin in strong hot potassium hydroxid solution will show a greenish color that suddenly disappears as the heating is continued. The disappearance of the color shows that the coumarin has been converted into the salicylate and heating should be discontinued. Take up the melt with a few cc. of water, acidify the solution with sulphuric acid and extract in a small separatory with 5-10 cc. of benzol. Benzol is preferred to any other solvent because of its low density, low solvent power for mineral acids, and because it will not dissolve any protocatechuic acid formed from vanillin that might possibly have been carried over with the ether. Remove the acid solution from the separatory and wash the benzol with a few cc. of water. After washing, filter the benzol into a test tube and test for salicylic acid with 1-2 cc. of water, containing a few drops of ferric chlorid solution. If no color develops on shaking, add 1-2 drops of N/10 sodium hydroxid solution to neutralize any trace of mineral acid that may be present and prevent the development of the purple color. This test can be conducted easily in 15 minutes, takes only 10 cc. of extract, and does not require dealcoholization or any complicated apparatus. The only evaporation necessary, that of the ether, can be done on a steam bath without appreciable loss. The change of color on fusion indicates its own end point. Approved. (4) That methods of analysis for imitation vanilla preparations containing large quantities of coumarin and vanillin be studied. Approved. (5) That the applicability of Hortvet and West's method1 for alcohol in orange and lemon extract, with F. M. Boyle's details for alcohol in ginger extract, be considered in connection with the official methods and other available methods. Boyle's method is as follows: To 25 cc. of the ginger extract, add 50 cc. of water, saturate with salt and shake with 75 cc. of petroleum ether. Allow to stand for 10 minutes, draw off the lower layer into a 200 cc. flask. Wash the petroleum ether with 50 cc. of saturated salt solution. This washing must be done carefully with moderate shaking, to avoid the formation of an emulsion. A slight emulsion at this point may be broken up by pouring back and forth into two separators. Add this wash water to the 200 cc. flask and make up to the mark with salt solution. Filter through a rapidly acting folded filter and determine the alcohol in 100 cc. of the filtrate by distillation. Approved. (6) That Mitchell's polarization method for lemon and orange extracts be studied for the purpose of determining the most accurate 1 J. Ind. Eng. Chem., 1909, 1: 84. 2 Assoc. Official Agr. Chemists, Methods, 1916, 262. factors to be used, especially with reference to the natural variations in the oils and the influence of dilution. Approved. (7) That Albright's details of the Kleber method for citral in lemon and orange oils1 be studied. It is recommended that the method for the detection of the adulteration of lard with fats containing tristearin' be adopted as a tentative method. Approved. SPICES AND OTHER CONDIMENTS. It is recommended (1) That the associate referee's modification of the distillation method for determining moisture in whole spices3 be further studied with a view to its adoption by the association. Approved. (2) That the method for the determination of volatile oil in mustard seed and mustard substitutes' be adopted as tentative. Approved. CACAO PRODUCTS. No recommendations were received from the referee. Your committee, however, has been informed that the referee has had under investigation methods for the detection of adulteration in cocoa butters. It is therefore recommended that these studies be continued. Approved. 1 J. Assoc. Official Agr. Chemists, 1920, 3: 417. 2 Ibid., 4: 200. Ibid., 3: 428. COFFEE. It is recommended (1) That the Gorter method for the determination of caffein in coffee1 be dropped. Approved. (2) That the Stahlschmidt method for the determination of caffein in coffee' be not made official this year. Approved. (3) That the Fendler-Stüber method for the determination of caffein in coffee2 be adopted tentatively. Approved. (4) That the Fendler-Stüber method for the determination of caffein in coffee2 be tried on other coffees, including raw coffee, with a view to its adoption as official next year. (1) That the modified Corper-Bryan method for the electrolytic determination of lead in baking powder3 be adopted as a tentative method. (First reading.) Approved. (2) That a further study be made of the electrolytic method proposed by Holbrook and McCreary, which uses a rotating cathode, and operates directly in an aqueous phosphoric acid suspension of the powder without preliminary hydrolysis of the starch. Approved. (3) That a study be made of the electrolytic separation and determination of zinc in baking powder. Approved. (4) That a study be made of Chittick's method for the determination of lead in baking powders". (5) That in view of the fact that Wichmann's modification of the Seeker-Clayton method gives difficulty as applied to modern baking powders, no further study be made of this method at the present time. Approved. (6) That the Ross-Wagner method for total fluorids1 be studied. Approved. (7) That efforts be made to develop a commercial method for the determination of zinc in baking powders. Approved. REPORT OF COMMITTEE ON EDITING METHODS OF ANALYSIS2. Your committee on Editing Methods of Analysis begs leave to report that the instructions given by the association at the 1916 meeting3 have been carried out as follows: (1) The following general reference tables have been removed from the text of the several chapters and inserted in a separate chapter designated as Chapter XXX: 1 Munson and Walker's Table. For calculating dextrose, invert sugar alone, invert sugar in the presence of sucrose, etc. 2 Kröber's Table". For determining pentoses and pentosans. 3 Table for densities of solutions of cane sugar at 20°C.". 4 Table of temperature corrections for changing percentages of sugar by specific gravity to true values at 20°C.". 5 Geerlig's Table. For dry substances in sugar-house products by the Abbé refractometer, at 28°C. 6 Table of corrections for temperature to be used in conjunction with Table No. 59. 7 Alcohol Table1o. For calculating the percentages of alcohol in mixtures of ethyl alcohol and water from their specific gravities. 8 Alcohol Table11. For calculating the percentages of alcohol in mixtures of ethyl alcohol and water from their Zeiss immersion refractometer readings at 17.5°-25°C. |