Lead Limit Test

Lead Determine as directed under Lead Limit Test, Appendix MB, using a solution of 2 g of sample in 20 mL of water, and 2 pig of lead (Pb) ion in the control. 

Lead Determine as directed for Method I in the Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB. 

Lead Determine as directed for Method I in the Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB, using a 10-g sample. Oxalate Neutralize 10 mL of a 1 10 aqueous solution with 6 N ammonium hydroxide, add 5 drops of 2.7 N hydrochloric acid, cool, and add 2 mL of calcium chloride TS. No turbidity develops. 

Lead Determine as directed under Lead Limit Test, Appendix IIIB, using a Sample Solution prepared as directed for organic compounds, and 5 p.g of lead (Pb) ion in the control. Loss on Drying Determine as directed under Loss on Drying, Appendix IIC, drying the sample at 105° for 3 h. Optical (Specific) Rotation Determine as directed under Optical (Specific) Rotation, Appendix IIB, using a solution containing 8 g of a previously dried sample in sufficient 6 N hydrochloric acid to make 100 mL. 

Standard Preparation On the day of use, dilute 3.0 mL of LeadNitrate Stock Solution (seethe Flame Atomic Absorption Method under Lead Limit Test, Appendix 11114) to 100 mL with water. Each milliliter of the Standard Preparation contains the equivalent of 3 pig of lead. 

Assay Dissolve about 500 mg of sample, accurately weighed, in 25 mL of 50% alcohol previously neutralized with 0.1 IV sodium hydroxide, add phenolphthalein TS, and titrate with 0.1 IV sodium hydroxide. Each milliliter of 0.1 A sodium hydroxide is equivalent to 12.21 mg of C7H602. Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix IIIB, using a 10-g sample. 

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