Increase in the sensitivity of the fluorescent reaction of the complexing of aluminium with morin using surfactant agents

ANALYSTANALYST Pub Date: DOI: 10.1039/AN9830801386

Abstract

The effects of surfactants on fluorescence analysis were studied. The addition of non-ionic surfactants (ethylene oxide - propylene oxide condensates) to a metal complex solution causes a remarkable enhancement of fluorescence, by which means the sensitivity of the fluorimetric determination of aluminium is increased ten-fold over conventional methods.

The optimum conditions in which the increase in fluorescence intensity is produced were studied and are as follows: 3% surfactant, pH 3.8 in acetic acid - acetate buffer at 25 °C; and the intensity of fluorescence is measured at 495 nm and excited at 430 nm. Using a morin concentration of 0.005% in the solution under analysis, the calibration graph is linear up to 35 p.p.b. (35 parts in 109) of aluminium. The relative standard deviation for the analysis of ten replicates of a solution containing 2 p.p.b. of aluminium is 3%; when it contains 10 p.p.b. the relative standard deviation is 2%.

The detection limit of the method is 0.2 p.p.b., using an excitation slit of 10 nm and an emission slit of 5 nm.

From the study of interfering ions it was deduced that the presence of surfactants gives a higher selectivity than a conventional method.

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