The analytical blank: sources and effects on lead analyses

The influence of the analytical blank on the reliability of an analysis is often of paramount importance. It is shown that the magnitude of the blank and the degree of uncertainty associated with it usually limits the ability to complete quantitative analyses at lower concentration levels. Specific sources of lead contamination are discussed and data are presented that indicate the possible contributions from each source. Although exceptions surely occur, it appears that lead contributions from the laboratory environment and/or ancillary analytical equipment and materials are often the primary factor in determining the blank level and the variability therein.