Analytical methods used by industry for lead in infant formula

The lead content of liquid infant products has been a prime focus of regulatory, industrial, and private analysts for some time. The principal source of Pb in these products is the solder used in 3-piece can manufacture. Voluntary surveys by the Infant Formula Council member companies from 1978 to present show that even low 1978 levels have been significantly reduced. Two procedures, anodic stripping voltammetry and electrothermal atomization (graphite furnace and carbon rod) atomic absorption spectrophotometry, are currently used by industry analysts. The results of 2 comparison studies provide a means of estimating the reliability of the procedures. Results of thousands of trace Pb determinations have demonstrated that steps to ensure the validity of results must be integrated into the entire analytical scheme. Quality control practices are described. Control of the laboratory environment is essential for ultimate sensitivity, and the design and performance of a trace metals analysis facility are discussed.