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|Type:||Artigo de periódico|
|Title:||Flow-injection Determination Of Low Levels Of Ammonium Ions In Natural Waters Employing Preconcentration With A Cation-exchange Resin|
Freire dos Reis B.
Bergamin Fo. H.
|Abstract:||Ammonium ions in natural waters at the 50 gmg 1-1 level were determined using Nessler reagent after preconcentration in a cation-exchange column coupled to a flow-injection analysis (FIA) system. The loading cycle, the elution cycle and the regeneration cycle were programmed for the resin used. The zone sampling approach using a computer-controlled commutator was employed in the FIA sytem design. Flow rates, resin loading, elution time, loop dimensions and resampling times for the zone sampling, column and coils dimensions, sensitivity and reproducibility were studied. The detection limit was improved tenfold over an earlier method that did not use a concentration step. A throughput of 45 sample analyses per hour was achieved for samples with concentration ranging from 50 to 500 μg 1 -1. The result show agreement to better than 99% with those obtained by the manual procedure. © 1992.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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