Fluorimetric determination of aluminium in serum

Abstract

A convenient fluorimetric method for the routine determination of aluminium in serum has been developed using lumogallion [4-chloro-3-(2,4-dihydroxyphenylazo)-2-hydroxybenzene-1-sulphonic acid]. Losses of aluminium during deproteinisation of the serum were prevented by treatment with a combination of 20 or 30%m/V trichloroacetic acid (TCA) and 5%m/V TCA. Iron(III) was removed by extraction into chloroform with capriquat (methyltrioctylammonium chloride) as an Fe³⁺-lumogallion-capriquat ternary complex. The interference from Cu²⁺ was eliminated by using thiosulphate as a masking agent. The detection limit was 3.6 ng ml^–1 and the calibration graph was linear up to 1.4 µg ml^–1 of aluminium. Using the proposed method, the average concentration of aluminium in the serum of healthy subjects was found to be 6.8 ng ml^–1, in agreement with values reported in the literature.