Multivariate optimization and validation of an analytical method for the determination of cadmium in wines employing ET AAS

this work describes the optimization and validation of a direct method employing electrothermal atomic absorption spectrometry (et aas) for the determination of cadmium in wine. the optimization step was carried out using a two-level full factorial design, involving the followings factors: pyrolysis time (10 s) and temperature (600 oc), atomization temperature (1300 oc) and modifier mass (15 μg). under the optimized conditions, a characteristic mass of 0.7 pg and limits of detection and quantification of 0.030 and 0.100 μg l-1, respectively, were obtained using a sample volume of 20 μl. the precision expressed as relative standard deviation (rsd %) was 0.30, 0.37 and 0.49% for wines with cadmium concentrations of 1.286, 0.266 and 0.356 μg l-1, respectively. the accuracy of the new direct determination methodology applying et aas was assessed by comparison with an acid digestion methodology, also with determination by et aas, using five wine samples. the proposed method was applied for the determination of cadmium in 30 brazilian wine samples. the cadmium content varied from 0.146 to 1.563 μg l-1; all these values are lower than the permissible maximum level stipulated by the international organization of vine and wine (oiv) and also by brazilian legislation, which is 10 μg l-1.