The direct determination of aluminium in aqueous solutions by differential pulse polarography is described. If the pH is carefully controlled to 4.00 ± 0.01, there is a linear relationship between the peak height of the polarographic wave and the aluminium concentration up to 2.5 × 10-5 mol dm-3. The coefficient of variation is about 4% at the 10-5 mol dm-3 level. With increasing aluminium concentrations, the relationship ceases to be linear, and above 9 × 10-5 mol dm-3, the peak splits, probably because of hydrolysis and polymerisation. Na+, NH4+, Mg2+ and Ca2+ interfere at levels 100 times greater than that of the aluminium whereas Fe2+, Fe3+, Cu2+, Zn2+, Ni2+, NO3-, ClO4-, Cl- and SO42- do not interfere.
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