On-line aluminium preconcentration on chelating resin and its FIA-spectrofluorimetric determination in foods and dialysis concentrates.
A new, sensitive and rapid spectrofluorimetric flow-injection method, is presented for the determination of trace levels of aluminium based on the formation of a fluorescent complex between aluminium and 5,7-dibromo-8-quinolinol (DBQ) and its extraction into diethylether (lambda(exc) = 400 nm, lambda(em) = 525 nm). Experimental conditions such as pH, reagent concentration, flow-rates, sample volume, extraction coil length, etc., have been optimized for on-line and batch procedures. The detection limits are 1 ppb and 0.3 ppb for batch and on-line systems respectively. The coeflicient of variation is 3.0% at the 4 ppb level for the FIA system. To remove interferences and to preconcentrate aluminium, a chelating resin microcolumn which was able to selectively complex A1(III) and was obtained by immobilizing Chromotrope 2B on AG1-X8 ion-exchange resin, was incorporated into the FIA system. The proposed method was successfully applied to determine aluminium in tap water, food samples and dialysis solutions.
Fernández
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Departamento de Química Analítica, Facultad de Ciencias Químicas de la Universidad Complutense, 28040 Madrid, Spain.
Conde
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Gutiérrez
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Cámara
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