Determinação simultânea de chumbo e cádmio em sangue por espectrometria de absorção atômica com forno de grafite

Blood lead and cadmium levels have been used to evaluate recent human exposure to these metals. Graphite Furnace Atomic Absorption Spectrometry (GFAAS) is the most suitable technique for lead and cadmium determinations in biological fluids due to its ability in detecting low concentrations of metals, and for using small amount of sample. The objective of this study was to establish and to validate a methodology for simultaneous determination of lead and cadmium in blood by GFAAS technique. Blood samples were diluted with Triton X-100 in HNO 3 , and a mixture of NH 4 H 2 PO 4 and Mg(NO 3 ) 2 solutions was used as chemical modifier. The analytical conditions were optimized and the best pyrolysis and atomization temperatures were 500oC and 1500oC, respectively. For validation, certified reference materials NIST SRM 955b (Lead in bovine blood) and NIST SRM 966 (Toxic metals in bovine blood) were used. The evaluated parameters for lead and cadmium were: linearity (5.0 to 100.0 µg.L -1 and 0.3 to 3.0 µg.L -1 ), accuracy (99.9% and 97.7%), precision (RSD = 3% and 13%), detection limit (0.54 µg.L -1 and 0.06 µg.L -1 ), and quantification limit (1.8 µg.L -1 and 0.21µg.L -1 ), respectively. The proposed method is fast, sensitive and suitable for simultaneous determination of lead and cadmium in blood samples from populations with occupational or environmental exposure, including children.