Sensitive and selective determination of aluminium by peroxyoxalate chemiluminescence detection of the lumogallion complex

For the first time, the feasibility of employing the reaction of bis(2,4,6- trichlorophenyl) oxalate with hydrogen peroxide, i.e. peroxyoxalate chemilu minescence (PO-CL) reaction, for the determination of Al via chemical excit ation of the Al-lumogallion complex is demonstrated. Experimental factors t hat affect the CL signal, such as pH, solvent and buffer compositions, and CL reagent concentrations were investigated. When compared to the use of fl uorescence (FL) for the detection of the Al-lumogallion complex or the use of PO-CL reaction for the detection of the Al-8-hydroxyquinoline complex, t he use of PO-CL reaction for the detection of the Al-lumogallion complex wa s found to exhibit higher tolerance towards interferences from a variety of inorganic and organic matrix species. For example, in CL detection, the to lerance limits (defined as the concentration ratio of the matrix ion to Al giving rise to a change in the peak height of the CL or FL signal of the Al working solution by a magnitude of 3% as a certain amount of a matrix spec ies is added) for Fe3+, Fe2+ and citrate ions using lumogallion as the chel ating agent for the determination of Al were 25, 14 and 170, respectively, whereas in FL detection, the corresponding tolerance limits were 1, 0.1 and 2, respectively. Under optimized conditions, the limit of detection for Al was ca. 0.042 mug l(-1) (3 sigma) and the calibration plot from 0.582 to 5 33 mug l(-1) was linear (r = 0.999). The applicability of the present CL me thod was demonstrated for the sensitive and selective determination of trac e Al present in natural water samples. The recoveries of Al were found to f all in the range between 90.4 and 109.7% and the average precision was 4.7% . (C) 2001 Elsevier Science B.V. All rights reserved.