Determination of lead and aluminium in port wine by electrothermal atomic absorption spectrometry

Abstract

Methods for the determination of lead and aluminium in port wine by electrothermal atomic absorption spectrometry based on the stabilized temperature platform furnace concept are described. Except for the dilution step, no sample preparation was required, thereby enabling the direct determination of the elements with little chance of contamination. The determination were performed in the linear range 1.9–100 µg l^–1 for lead and 1.6–50 µg l^–1 for aluminium in the port wine samples, after appropriate dilution (usually 1 + 9 for lead and 1 + 24 for aluminium). These correspond to detection limits of 19 and 40 µg l^–1 for lead and aluminium, respectively, in undiluted samples. The precision was better than 4%(at a concentration level of about 25 µg l^–1) for lead and 3%(at a concentration level of about 35 µg l^–1) for aluminium. The comparison of the results obtained for 18 port wine samples by direct interpolation of a calibration graph prepared with aqueous standard solutions and by the standard additions method produced shifts that were always less than 10% for lead and 8% for aluminium. The simplicity and rapidity of each analysis (a graphite furnace programme time of 159 s for lead and 85 s for aluminium) makes this method most attractive for routine analysis.