Quantitative analyses of cadmium: quality assured?

Legislation has been a powerful stimulus for measuring the concentrations of cadmium in many different matrices. Unfortunately, much of the quantitative data in the literature is flawed because of a paucity of information on the reliability of sampling and measurement. Non-specific analytical methods, inaccurate calibration, lack of matrix reference materials, poor laboratory technique in general, lack of statistical control, and ignorance of contamination all militate against gathering truly valid data. The implications for bioavailability of chemical and physical speciation also need to be considered, especially in the analysis of airborne particulates and foodstuffs. Effective quality assurance serves several distinct purposes: (1) to allay analysts' concern for the quality of their work; (2) to discharge management's responsibility for the cost and quality of the laboratory's output; (3) to inform users of the quality of the data sets; and (4) to provide archival data and documentation.