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 . er arsenic is present in any soluble form, in asolution in which hydrogen is being evolved by the action ofzinc upon hydrochloric or sulpliuric acid. There are two methods of the application of this test; theone long
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 . er arsenic is present in any soluble form, in asolution in which hydrogen is being evolved by the action ofzinc upon hydrochloric or sulpliuric acid. There are two methods of the application of this test; theone long known as Marshs test, and preeminently adapted forforensic and quantitative detection and estimation of arsenic,the other of recent device, and preferable for the ready andprompt qualitative detection of arsenic. A complete but simple form of apparatus for Marsli^s test isrepresented in Fig. 9 ; it consists of a generating-flask ^, of about4 to 6 ounces capacity, provided by means of a twice-perforatedcork, or rubber stopper, with a funnel-tubS and a delivery-tube,which last is connected by rubber corks with a wider glass tube, f REAGENTS. 29 c, loosely filled with fragments of calcium-chloride; to the oppo-site end of this drying-tube is attached a long piece of narrowtubing of hard German glass, d^ drawn out into a capillary end,and bent up so as to form a vertical Fig. 9. The test consists in introducing into the flask a pure granu-lar zinc or magnesium, and a little water; when the apparatusis tightly fitted, hydrochloric or sulphuric acid is added throughthe funnel-tube. It is necessary in each case first to ascertain the purity ofthese substances. After the evolution of g-as has continuedlong enough to expel the atmospheric air, the reduction-tube, d^is heated to redness for about ten minutes, the escaping gas islighted, and a piece of white porcelain held in the flame. Ifno dark deposit takes place, either in the tube or on the porce-lain, the liquid to be tested
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Keywords: ., bookcentury1, bookdecade1870, booksubjectpharmaceuticalchemistry
