Validation of a Method To Quantify Copper and Other Metals in Olive Fruit by ETAAS. Application to the Residual Metal Control after Olive Tree Treatments with Different Copper Formulations
An electrothermal atomization atomic absorption spectrometry method was validated to quantify residues of copper, aluminum, cadmium, chromium, iron, lead, and nickel in olive fruit. The linearity
ranges under the optimized conditions were 0.19-20.0, 1.11-50.0, 0.02-2.0, 0.15-20.0, 0.80-
20.0, 0.35-50.0, and 0.60-50.0 íg/L, respectively. The limits of quantification were, expressed in
nanograms per gram of dry weight, 12.6, 74.0, 1.34, 10.0, 53.4, 23.4, and 40.0, respectively. For all
of the metals the precision of the instrumental method was <6.3% and that of the analytical method
was always <10%, except for aluminum, for which the precision was 12%. The accuracy of the method
was evaluated according to the standard additions method, the recoveries being >90% for all of the
added concentrations. An interference study was also carried out in a simulated matrix, and it was
verified that the deviations of the expected values were <6% for all of the metals. The method was
applied to the monitoring of the residues of the referred metals in olive fruits collected from trees
pulverized with three different copper formulations available on the market to control fungal diseases.
