SYNTHESIS AND APPLICATION OF FUNCTIONALIZED RESIN FOR PRECONCENTRATION OF CADMIUM AND LEAD AND DETERMINATION BY FAAS

Preconcentration methods are required when the concentration of the analytes in the samples is below the level of detection of the analytical techniques and/or the matrix interferes in the determination of the same. In view advantages of these preconcentration methods, a syntheses of amberlite XAD-4 functionalized with 5-(4-dimethylaminobenzylidene)-rhodanine for solid phase extration of cadmium and lead procedure has been proposed, aiming the determination of these analytes in environmental samples and determination by flame atomic absorption spectrometry (FAAS). The optimization of the preconcentration system was performed using response surface methodology by Box-Behnken planning. The studied factors were buffer concentration (0.001-0.009 mol/L), pH (5.5-9.5), sampling rate (2.0-8.0 mL/min) and elution flow (2.0-8.0 mL/min). The appropriate conditions obtained for the procedure were: pH 5.75, concentration buffer 0.009 mol/L, sampling rate 4.0 mL/min and elution flow 4.0 mL/min. Under these conditions, the analytical parameters procedure were obtained, quantification limits for Cd and Pb were 2.58 µg/L and 3.33 µg/L respectively. The precison was determined by the standard deviation relative to the lowest and highest value of the calibration curve and these were less than 10%. The enrichment factor was 26 for Cd and 43 for Pb. The developed method was applied for the determination of these analytes in samples of tap water, estuarine water and mineral water from the city of Ilhéus, Ba. The accuracy of the method was performed using the analyte addition and recovery test and the values obtained were 95.0% - 102.3% for Cd and 94.5% - 96.5% for Pb and certified material, NIST 1566b oyster tissue. The procedure developed proved simple, sensitive and low cost, presenting good analytical parameters and can be applied in the determination of cadmium and lead in environmental samples.