[en] An alizarin-modified electrode for the voltammetric determination of aluminium(III) is reported. The single-use modified electrode is simply prepared by dip-coating a high-density graphite electrode in an N,N-dimethylformamide solution of alizarin. Optimum experimental conditions for aluminium(III) determination include a solution pH of 8.4±0.2, an accumulation time of 1 min and use of the differential-pulse mode for measurement of the oxidation peak of the aluminium(III)-alizarin complex. The detection limit is 1.5x10^-7 M, the response is linear up to 1.0x10^-5 M and the relative standard deviation for replicate preparations of the electrode [at 7.5x10^-6 M Al(III)] is 3.8%. The determination of aluminium in soil samples is reported. (author). 14 refs.; 5 figs.; 2 tabs