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 . course of analytical investigation, each precipitationmust be complete; to insure this, the reagent must be addedgradually, allow^ing the precipitate to subside after each addi-tion, until no further precipitate is p
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 . course of analytical investigation, each precipitationmust be complete; to insure this, the reagent must be addedgradually, allow^ing the precipitate to subside after each addi-tion, until no further precipitate is produced. In almost all cases separation of precipitates is aidedby the application of gentle heat. The separation of the supernatantmenstruum from a precipitate is efiectedeither by filtration and subsecjuent wash-ing of the precipitate upon the filter bymeans of a washing-bottle (Fig. 1), or,where the precipitate speedily and com-pletely subsides, by decantation. As arule, funnels and filters must be small,and proportionate to the amount of theprecipitate and the menstruum ; filtersshould be cut so as not to project overthe rim of the funnel, and it is also ad-visable to moisten the filter upon thefunnel with distilled water, by means of the washing-bottle,previous to passing the fluid through it. Decaiitation isefiected either by pouring off the supernatant clear part of. Fig. 1. OPERATIONS. 17 tlie fluid by simply inclining the vessel and allowing the fluidto flow down a glass rod (Fig. 2), or by drawing it off by meansof a small glass siphon or a pipette (Fig. 3).
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Keywords: ., bookcentury1, bookdecade1870, booksubjectpharmaceuticalchemistry
