Lead Limits

Tin-lead can be substituted for tin for other purposes, although the toxicity of lead limits the field of application. The corrosion resistance is usually no better than that of unalloyed tin, but there may be some saving of cost in applications such as wash-boilers and other vessels for non-potable liquids and light engineering components formed from sheet metal. Heavily coated terne-plates may be used for the fuel tanks of stoves and vehicles. 

Sulfuric Acid Solutions Voltammetric properties of pure lead electrodes have been studied in different media, but owing to obvious applications in lead-acid batteries, most data relate to sulfuric acid solutions. Typically, voltammetric curves of lead, limited by hydrogen... 

Metal Contaminants. There is increasing interest in the lead, sodium, and other metallic constituents of wine. The present lead limit is 0.6 mg/liter. While sodium is a normal constituent of wines, cation exchange resins may unduly increase its level. Suggested limits for sodium vary from 60 to 300 mg/liter in different countries. Wine as a low-sodium high-potassium beverage in diets for hypertension patients makes it apparent that stricter limits on sodium may be applied. 

Heavy Metals Limits (Policy) The Committee on Food Chemicals Codex notes the importance of providing limits for individual heavy metals as required by the source and composition of individual food additives. Thus, it has decided to remove from most monographs the general heavy metals (as lead) limits and tests and, based on the current level and availability of scientific information and on the policy stated below, to replace them with limits and tests for specific heavy metals such as lead, cadmium, and mercury as may be relevant to each substance. 

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. 

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