Electrothermal atomic absorption spectrometric determination of cadmium, copper, iron, lead, and selenium in fruit slurry: analytical application to nutritional and toxicological quality control.

A method is described for direct determination of cadmium, copper, iron, lead, and selenium in slurried fruit samples by electrothermal atomic absorption spectrometry. The fresh samples were suspended in Triton X-100 and shaken with 10 g zirconia spheres until a slurry was formed. The graphite furnace conditions were optimized for each element. The detection limits were 0.3, 3.5, 15.0, 0.5, and 10.0 ng/g for Cd, Cu, Fe, Pb, and Se, respectively. Accuracy and precision were checked against sample mineralization in a microwave acid-digestion bomb. Results for analyses of National Institute of Standards and Technology standard reference materials agreed closely with certified values. Analytical application of this method was tested with 40 samples of 8 widely consumed fruit species. The mean values (referred to fresh weight of edible fraction) for each fruit species had ranges of 0.0003-0.050 microgram/g for Cd, 0.316-1.094 micrograms/g for Cu, 2.00-5.50 micrograms/g for Fe, 0.050-0.396 microgram/g for Pb, and 0.010-0.020 microgram/g for Se. The proposed method is useful for routine multielemental analysis in nutritional and toxicological quality control of fruits and similar foodstuffs.