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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/6426

Title: Single drop micro-extraction with O,O-diethyl dithiophosphate for the determination of lead by electrothermal atomic absorption spectrometry
Other Titles: Talanta
Authors: Maltez, Heloísa França
Borges, Daniel L. G.
Carasek, Eduardo
Welz, Bernhard
Curtius, Adilson José
Keywords: Single drop micro-extraction;Diethyl dithiophosphate;Lead determination;Electrothermal atomic absorption spectrometry;Chloroform;Tungsten-treated platform
Issue Date: 2008
Abstract: Lead was extracted as the O,O-diethyldithiophosphate (DDTP) complex from aqueous solution into a drop of CHCl3 immersed in the solution.Unlike previously reported procedures using single drop micro-extraction (SDME) for the extraction of inorganic analytes, the complexation reaction was conducted in the aqueous phase, as the ammonium salt of DDTP is soluble in water. The concentration of DDTP was optimized as 0.01% (m/v). Experimental parameters such as extraction time (7 min) and organic drop volume (3 L) were optimized and selected as a compromise between sensitivity and stability of the organic drop in the aqueous solution. The sensitivity with electrothermal atomic absorption spectrometry (ET AAS) was low, probably due to infiltration of the organic drop into the totally pyrolytic graphite platform. To overcome this problem, tungsten (400 g) was thermally deposited onto the platform surface. A short pyrolysis stage at 700 ◦C was included to reduce background absorption. Under these conditions, five certified reference materials with different characteristics were analyzed using calibration against aqueous standards submitted to the SDME procedure, resulting in good agreement between certified and found concentration values at a 95% confidencelevel. Two real water samples have also been analyzed, with recoveries ranging from 85 to 92% after enrichment with Pb. An enhancement factor of 52 allowed a detection limit of 0.2 gL−1 or 0.04 g g−1, demonstrating the high detection capability of the proposed procedure, with a relative standard deviation typically below 4%.
Description: Acesso restrito: Texto completo. p. 800-805.
URI: http://www.repositorio.ufba.br/ri/handle/ri/6426
ISSN: 0039-9140
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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