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1.
Anal Sci ; 21(8): 939-44, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16122164

RESUMO

In this work, flame atomic absorption spectrometry (FAAS) was used as a detector for the determination of zinc in natural water samples with a flow-injection system coupled to solid-phase extraction (SPE). In order to promote the on-line preconcentration of zinc from samples a minicolumn packed with 35 mg of a styrene-divinylbenzene resin functionalized with (S)-2-[hydroxy-bis(4-vinylphenyl)methyl]pyrrolidine-1-carboxylic acid ethyl esther was utilized. The system operation was based on Zn(II) ion retention at pH 9.5 +/- 0.5 in such a minicolumn with analyte elution, at the back flush mode, with 1 mol L(-1) HCl directly to the FAAS nebulizer. The influence of the chemical (sample pH, buffer concentration, HCl eluent concentration and effect of the ionic strength) and flow (sample and eluent flow rates and preconcentration time) parameters that could affect the performance of the system were investigated as well as the possible interferents. At the optimum conditions, for 2 min of preconcentration time (9.9 ml of sample volume), the developed methodology presented a detection limit of 1.1 microg L(-1), a RSD of 3.5% at 10 microg L(-1) and an analytical throughput of 24 h(-1). Whereas, for 4 min of the preconcentration time (19.8 ml of sample volume) a detection limit of 0.98 microg L(-1), a RSD of 6.5% at 5 microg L(-1) and a sampling frequency of 13 h(-1) are reported.


Assuntos
Espectrofotometria Atômica/métodos , Estireno/química , Compostos de Vinila/química , Água/química , Zinco/química , Ionização de Chama , Resinas de Troca Iônica/química , Estrutura Molecular
2.
Talanta ; 67(1): 121-8, 2005 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18970145

RESUMO

This paper reports the development of a new strategy for low-level determination of copper in water samples by using a flow-injection system coupled to solid-phase extraction (SPE) using flame atomic absorption spectrometry (F AAS) as detector. In order to preconcentrate copper from samples, a minicolumn packed with a styrene-divinylbenzene resin functionalized with (S)-2-[hydroxy-bis-(4-vinyl-phenyl)-methyl]-pyrrolidine-1-carboxylic acid ethyl ester was used and the synthesis procedure is described. System operation is based on the on-line retention of Cu(II) ions at pH 9.0+/-0.2 in a such minicolumn with posterior analyte elution with 2moll(-1) HCl directly to the F AAS nebulizer. The influence of several chemical (sample pH, buffer concentration, HCl eluent concentration and effect of the ionic strength) and flow (sample and eluent flow rates and preconcentration time) variables that could affect the performance of this system were investigated as well as the possible interferents. At optimized conditions, for 2min of preconcentration time (13.2ml of sample volume), the system achieved a detection limit of 1.1mugl(-1), a R.S.D. 1% at 20muggl(-1) and an analytical throughput of 25h(-1), whereas for 4min of preconcentration time (26.4ml of sample volume), a detection limit of 0.93mugl(-1), a R.S.D. 5.3% at 5mugl(-1) and a sampling frequency of 13h(-1) were reported.

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