Manual of chemical analysis as applied to the examination of medicinal chemicals : a guide for the determination of their identity and quality, and for the determination of their identity and quality, and for the detection of impurities and adulterations : for the use of pharmaceutists, physicians, druggists, and manufacturing chemists, and of pharmaceutical and medical students . trength. Tests for the Detection of Alcohol in Chloroform, 1. Strong sulphuric acid, to which a little potassium bichro-mate has been added, when shaken with an equal bulk of chlo-roform, will turn green, if the latt
Manual of chemical analysis as applied to the examination of medicinal chemicals : a guide for the determination of their identity and quality, and for the determination of their identity and quality, and for the detection of impurities and adulterations : for the use of pharmaceutists, physicians, druggists, and manufacturing chemists, and of pharmaceutical and medical students . trength. Tests for the Detection of Alcohol in Chloroform, 1. Strong sulphuric acid, to which a little potassium bichro-mate has been added, when shaken with an equal bulk of chlo-roform, will turn green, if the latter contains alcohol. 2. Two volumes of chloroform and one volume of concen-trated sulphuric acid are mixed in a bottle closed with a glassstopper; after repeated agitation, the bottle is set aside for afew hours ; the liquid is then carefully diluted with about anequal bulk of water, the supernatant aqueous liquid is decantedinto a beaker, and so much of a mixture of pure barium carbon-ate in water is added, with constant stirring with a glass rod,as completely to neutralize the acid, so that, after gentle warm-ing, the cooled liquid does not change blue litmus-paper ; it isthen passed through a moist filter, and the filtrate tested withdiluted sulphuric acid. If the chloroform contained traces ofalcohol, this would have given rise to the formation of ethyl- CINCHONIA. 181. Fig. 58. sulphuric acid (sulphovinic acid), and subsequently to solublebarium ethyl-sulphate, contained in the filtered solution, and which is precipitated by sulphuric acidas barium sulphate. Consequently,the occurrence of a white precipitatewill be evidence of the presence of alco-hol. 3. A mixture of two volumes of thechloroform with five volumes of water iswarmed, in a test-tube, to about from 30°to 40° C.; after violent agitation for afew minutes, the liquid is passed througha moist filter, and to the filtrateis added a little solution of iodin-ized potassium iodide; liquor po-tassse is then gradually
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