Workshop on the determination of lead in foods by graphite furnace atomic absorption spectrometry: preliminary report.
Seven analysts with various degrees of trace element experience participated in a workshop on the determination of lead in foods containing 1-1000 ng lead/g. Each analyst independently performed 4 projects: contamination control, rapid screening for lead in canned milks, rapid determination of lead in foods, and solvent extraction determination of lead in foods. Accuracy and precision for all methods were good, and, using the solvent extraction method, analysts were able to accurately analyze milk containing 2 ng lead/g with a reproducibility standard deviation of 0.6 ng/g, including individual outliers, and 0.3 ng/g when outliers were rejected. Recovery at the 10 ng/g spiking level for milk averaged 107%. The results were exceptional considering that one of the analysts was a pesticide chemist, 5 other analysts spend only part of their time in trace element analysis, clean-room facilities were not used for any part of the study, the solvent extraction technique was preceded by a HNO3-HClO4 digestion and was relatively complex, and the labware used for the entire workshop including digestions was either Pyrex or uncleaned, disposable polystyrene test tubes. The results of the workshop demonstrate that accurate, background-level lead determinations can be made inexpensively in normal laboratories, provided analysts are properly instructed in contamination control.
D000818:Animals; D002417:Cattle; D005504:Food Analysis / Q000379:methods*; D006108:Graphite; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis; D007854:Lead / Q000032:analysis*; D008892:Milk / Q000032:analysis; D013054:Spectrophotometry, Atomic / Q000379:methods
D007854:Lead; D006108:Graphite