360 METHODS OF ANALYSIS [Chap, 



Caffein, Acetanilid, Quinin Sulphate and Morphin Sulphate in Mixtures. 



27 preparation of sample and solution.— tentative. 



Transfer to a separatory funnel an amount (containing not less than one fourth 

 grain of morphin) of the powdered sample equal to, or a multiple of, a unit dose, 

 add 20 cc. of water and 10 drops of dilute sulphuric acid, then extract with three 

 50 cc. portions of alcohol-free chloroform, wash each portion in a second separatory 

 funnel with 5 cc. of water and add the combined washings to the alkaloidal solu- 

 tion in the first separatory funnel. Filter the chloroform extracts through a small, 

 dry filter into a 200 cc. Erlenmeyer flask and distil by gentle heat to about 10 cc. 



28 CAFFEIN AND ACETANILID.— TENTATIVE. 

 Treat the chloroform residue as directed under 3 and 4. 



29 QUININ SULPHATE.— TENTATIVE. 



Add to the solution of quinin and morphin sulphates, obtained in 27, 4-5 cc. of 

 sodium hydroxid solution (1 to 10) and extract with four 40 cc. portions of chloro- 

 form, wash each portion with 5 cc. of water and pass the clear solvent through a 

 small, dry filter into a 200 cc. Erlenmeyer flask. Remove the solvent by gentle 

 distillation and titrate the residual quinin with N/50 hydrochloric acid as directed 

 under 23. 



30 MORPHIN SULPHATE.-TENTATIVE. 



Wash the filter, employed in 29, with 5 cc. of water and add to the aqueous 

 alkaline solution of the alkaloid. Now add 0.5 gram of ammonium chlorid (or an 

 amount slightly in excess of that required to free the morphin as well as convert 

 all sodium hydroxid to sodium chlorid) and, to the resulting ammoniacal solution, 

 add 45 cc. of chloroform and 5 cc. of alcohol, then extract in the usual way, washing 

 the solvent in a second separatory funnel with 5 cc. of water. After clearing, pass 

 the chloroform through a small, dry filter into a 200 cc. Erlenmeyer flask. Repeat 

 the extraction with three 40 cc. portions of chloroform, washing and filtering as be- 

 fore, finally collecting all the solvent in an Erlenmeyer flask and distilling to about 

 10 cc. Transfer with chloroform to a small, tared beaker, evaporate to apparent 

 dryness, add 0.5 cc. each of water and neutral alcohol, start crystallization by 

 stirring with a glass rod and finally evaporate to dryness. Cool and allow to stand 

 until the weight becomes constant. 



Check the weight of morphin, thus determined, by titration with N/50 sulphuric 

 acid, using a drop of methyl red as an indicator. Dissolve the alkaloid in 1-2 cc. 

 of warm, neutral alcohol, then add the standard acid to a faint red. Evaporate 

 most of the alcohol on a steam bath, adding, if necessary, sufficient acid to main- 

 tain the acid reaction. From the volume of acid used calculate the morphin sul- 

 phate. One cc. of N/50 sulphuric acid is equivalent to 7.58 mg. of morphin sulphate. 



Tragacanth. 



31 VOLATILE ACIDITY^.— tentative. 



The quantity of volatile (acetic) acidity developed in the acid hydrolysis of gum 

 tragacanth {Astragalus gummijer) affords a valuable index of the purity of this com- 

 modity when compared with results obtained by similar treatment of so-called 

 "Indian gum" {Cochlospernum gossypium and Sterculia urens). The term "vola- 

 tile acidity" expresses the nmnber of cc. of N/10 potassium or sodium hydroxid 

 required to neutralize the volatile (acetic) acid obtained by distilling with steam 

 the products of the action of boiling aqueous phosphoric acid on 1 gram of the gum. 



