Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . flask by means of100 cc. of concentrated hydrochloric acid (sp. gr. ). Add 5 grams of cuprouschlorid (CU2CI2) and distil. When the volume in the distillation flask is reduced to about 40 cc, add 50 concentrated hydrochloric acid by means of the dropping funnel and continuethe distillation until 200 cc. of the acid distillate have passed over. Then washdown the condenser and all the connecting tubes carefully, transfer these washingsand the contents of the
Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . flask by means of100 cc. of concentrated hydrochloric acid (sp. gr. ). Add 5 grams of cuprouschlorid (CU2CI2) and distil. When the volume in the distillation flask is reduced to about 40 cc, add 50 concentrated hydrochloric acid by means of the dropping funnel and continuethe distillation until 200 cc. of the acid distillate have passed over. Then washdown the condenser and all the connecting tubes carefully, transfer these washingsand the contents of the 3 Erlenmeyer flasks to a liter graduated flask and diluteto the mark. Mix thoroughly, pipette 400 cc. into an Erlenmeyer flask and nearlyneutralize with a saturated solution of sodium or potassium hydroxid, using a fewdrops of phenolphthalein as an indicator, keeping the solution well cooled. Continue as directed under 3 (C) beginning with neutralize with sodium bicar-bonate. The number of cc. of iodin used in this titration represents directlythe total per cent of arsenic in the sample expressed as arsenious oxid (AS2O3).. FIG. 5. APPARATUS FOR DISTILLATION OF ARSENIC CHLORID. TOTAL ARSENIOUS OXID. (The following methods determine arsenic, and antimony if present, as the -ousoxids, AS2O3 and SbaOs, respectively. Ferrous and cuprous salts vitiate the results.) Method C. Hedges Method,^ Modified.^—Tentative. 6 REAGENTS. The reagents and solutions used are described under 3. 7 DETERMINATION. Weigh an amount of the sample equal to the arsenious oxid equivalent of 100 the standard iodin solution, wash into an Erlenmeyer flask with 10-15 cc. of dilutehydrochloric acid (1 to 1), followed by about 100 cc. of water, and heat on the steam-bath to complete solution, at a temperature not exceeding 60°C. Cool, neutralize VII] INSECTICIDES AND FUNGICIDES 65 with sodium bicarbonate, add 4-5 grams in excess, and then sufficient 25% ammoniumchlorid solution to dissolve the precip
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