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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/14392

Title: Cloud point extraction for the determination of lead and cadmium in urine by graphite furnace atomic absorption spectrometry with multivariate optimization using Box–Behnken design
Other Titles: Spectrochimica Acta Part B: Atomic Spectroscopy
Authors: Maranhão, Tatiane de A.
Martendal, Edmar
Borges, Daniel L. G.
Carasek, Eduardo
Welz, Bernhard
Curtius, Adilson José
Keywords: Cloud point extraction;Graphite furnace atomic absorption spectrometry;Urine;Cadmium determination;Lead determination;Permanent modifier
Issue Date: 2007
Abstract: Cloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Pb and Cd in undigested urine by graphite furnace atomic absorption spectrometry (GF AAS). Aliquots of 0.5 mL urine were acidified with HCl and the chelating agent ammonium O,O-diethyl dithiophosphate (DDTP) was added along with the non-ionic surfactant Triton X-114 at the optimized concentrations. Phase separation was achieved by heating the mixture to 50 °C for 15 min. The surfactant-rich phase was analyzed by GF AAS, employing the optimized pyrolysis temperatures of 900 °C for Pb and 800 °C for Cd, using a graphite tube with a platform treated with 500 μg Ru as permanent modifier. The reagent concentrations for CPE (HCl, DDTP and Triton X-114) were optimized using a Box–Behnken design. The response surfaces and the optimum values were very similar for aqueous solutions and for the urine samples, demonstrating that aqueous standards submitted to CPE could be used for calibration. Detection limits of 40 and 2 ng L− 1 for Pb and Cd, respectively, were obtained along with an enhancement factor of 16 for both analytes. Three control urine samples were analyzed using this approach, and good agreement was obtained at a 95% statistical confidence level between the certified and determined values. Five real samples have also been analyzed before and after spiking with Pb and Cd, resulting in recoveries ranging from 97 to 118%.
Description: Texto completo: acesso restrito. p. 1019-1027
URI: http://repositorio.ufba.br/ri/handle/ri/14392
ISSN: 0584-8547
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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