Sulfate Limit Test

Sulfur Compounds (as S04) Dissolve 4 g of sample in 40 mL of water, add about 10 mg of sodium carbonate and 1 mL of 30% hydrogen peroxide, and evaporate the solution to dryness on a steam bath. Treat the residue as directed in the Sulfate Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB. Any turbidity produced by the sample does not exceed that produced by a control containing 280 p,g of sulfate ion (S04). 

Chloride Determine as directed in Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB. Any turbidity produced by a 40-mg sample does not exceed that produced by a control containing 20 ptg of chloride (Cl) ion. 

Calcium Content Dissolve about 1.5 g of sample, accurately weighed, in 100 mL of water containing 2 mL of 2.7 A hydrochloric acid. While stirring, preferably with a magnetic stirrer, add about 30 mL of 0.05 M disodium EDTA from a 50-mL buret, then add 15 mL of 1 A sodium hydroxide and 300 mg of hydroxy naphthol blue indicator, and continue the titration to a blue endpoint. Each milliliter of 0.05 M disodium EDTA is equivalent to 2.004 mg of calcium (Ca). Halides Determine as directed in the Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB. A 1.2-g sample shows no more turbidity than 0.7 mL of 0.020 A hydrochloric acid. 

Assay Dissolve about 0.4 g of sample, accurately weighed, in 20 mL of 16 100 sulfuric acid, add 5 mL of 85% phosphoric acid, dilute with approximately 50 mL of water, and immediately titrate with 0.1 N ceric sulfate, using orthophenanthroline TS as the indicator. Perform a blank determination (see General Provisions), and make any necessary correction. Each milliliter of 0.1 N ceric sulfate is equivalent to 5.585 mg of Fe. Chloride Heat 100 mg of sample, accurately weighed, with 25 mL of water and 2 mL of nitric acid until the sample dissolves. Cool, dilute to 100 mL with water, and mix. Take 10 mL of this solution, and dilute to 30 to 40 mL with water. Proceed as directed in the Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB, beginning with add 1 mL of silver nitrate TS... . Any turbidity produced does not exceed that shown in a control containing 20 pig of chloride (Cl). 

Chloride Determine as directed in the Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIA, using... 

Chloride Determine as directed in Chloride Limit Test under Chloride and Sulfate Limit Tests, Appendix IIIB. Any turbidity produced by a 400-mg sample does not exceed that produced in a control containing 20 jxg of chloride (Cl) ion. Lead Determine as directed under Lead Limit Test, Appendix IIIB, using a Sample Solution prepared as directed for organic compounds, and 4 p,g of lead (Pb) ion in the control. Loss on Drying Determine as directed under Loss on Drying, Appendix IIC, drying a sample at 105° for 4 h. 

Clarity and Color of Solution A 1 10 aqueous solution is colorless and has no more turbidity than a standard mixture prepared as follows Dilute 0.2 mL of Standard Chloride Solution (see Chloride and Sulfate Limit Tests, Appendix IIIB) with water to 20 mL add 1 mL of 1 3 nitric acid, 0.2 mL of a 1 50 dextrin solution, and 1 mL of a 1 50 silver nitrate solution mix and allow to stand for 15 min. 

Chloride and Sulfate Limit Tests, 757 Chloride Identification Test, 753 Chlorinated Compounds, 817 Chlorine, 99... 

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