Indirect micro-scale method for the determination of desferrioxamine and its aluminium and iron chelated forms in biological samples by atomic absorption spectrometry with electrothermal atomisation

Abstract

An indirect micro-scale method is described for the determination of desferrioxamine (DFA) itself and in its iron and aluminium complexed forms (FeA and AlA) in blood plasma and urine. AlA, FeA and DFA, after its conversion into FeA with an excess of iron, are selectively extracted with benzyl alcohol, and iron and aluminium are determined in the benzyl alcohol extract by electrothermal atomic absorption spectrometry using partition pyrolytically coated graphite tubes with a cuvette to prevent benzyl alcohol from spreading to the tube extremities.

The specificity of the method was assessed and the sensitivity is sufficient for the determination of DFA, FeA (44 µg l^–1) and AlA in blood plasma and urine after the administration of desferrioxamine as Desferal. However, because of the wide range of concentrations observed in biological samples (from 1 to 300 mg l^–1 of DFA) the use of two calibration graphs and sometimes a preliminary dilution of the high-concentration samples are required.

The use of this indirect micro-scale method for more than 1000 assays without particular problems has allowed the study of DFA pharmacokinetics.