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AOAC Official 934.09 Merbromin in Drugs First Action 1934_AOAC.rar

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AOAC Official 934.09 Merbromin in Drugs First Action 1934_AOAC.rar,AOAC Official 934.09 Merbromin in Drugs First Action 1934_AOAC.rar

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18.4.22AOAC Official Method 934.09Merbromin in DrugsFirst Action 1934A. Tests for PurityProcedure(a) Acidify portion of merbrom in laboratory solution with 10%H2SO4(w/v)andfilteroffprecipitate.Filtrateisonlyslightlyyellow.(b) PassH2Sintoportionoffiltrate.Noprecipitateorcoloringoccurs.(c) AddfewmL10%HNO3toanotherportionoffiltrateandadd0.1M AgNO3solution. No precipitate forms.B. Total Solids in Laboratory SolutionFinal ActionPipet 10 mL merbromin solution into tared, extra-wide-formweighing bottle and evaporate to dryness on steam bath. Let dryovernight in open bottle in desiccator containing H2SO4. Weigh.C. Determination of MercuryFinal ActionPipet 10 mL ca 2% merbromin laboratory solution into 500 mLtall beaker and evaporate to dryness on steam bath (or accuratelyweigh ca 0.2 g powder). Dissolve residue in 4 mL H2O and slowlyadd, with constant mixing, 10 mL H2SO4. Incline beaker and cau-tiously add small portions finely powdered KMnO4, mixing aftereach addition, until deep purple color shows that considerable ex-cesshasbeenadded.Letstand30min,mixingoccasionally.Mixtureshould still be purple.Add 100 mL H2O and mix thoroughly. Add small portions finelypowderedoxalicacid,mixingaftereachaddition,untilsolutionisclear.Filterthroughsmallfilterinto400mLbeaker,washoriginalbeakerandfilter until filtrate measures ca 200 mL, and pass H2S through solution20min.WarmonsteambathuntilprecipitateofHgSsettlesquicklyaf-terstirring,andagainpassH2Sthroughwarmsolution5min.Immedi-ately filter solution into weighed Gooch with glass fiber filter;thoroughly wash precipitate on filter with H2O, 3 times with alcohol,and then with 4 or 5 portions CS2, letting liquid run through cruciblewithout suction; finally wash with ether. Dry precipitate to constantweight at 100C and weigh as HgS. HgS 0.8622 = Hg.QualitativelytestdriedprecipitateforHgandotherheavymetals.If slow filtration occurs during washing with H2O, let precipitatedrain, and wash once with alcohol; then continue as directed.Refe