Abstract
An atomic absorption spectrometric method for the determination of trace amounts of lead after
adsorption of its 1-(2-pyridylazo)-2-naphthol (PAN) complex on microcrystalline naphthalene
has been developed. This complex was adsorbed on microcrystalline naphthalene in the
pH range 8.4–11.5 from large volumes of aqueous solutions of various alloys and biological
samples. After filtration, the solid mass consisting of the complex and naphthalene was dissolved
with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption
spectrometry. Lead was alternatively quantitatively adsorbed on 1-(2-pyridylazo)-2-naphthol-naphthalene adsorbent packed in a column and determined similarly. In this case, 0.5 g of lead was concentrated in a column from 500 ml of aqueous sample, where its concentration
was as low as 1.0 ng ml–1. Eight replicate determinations of 4.0 g ml–1 of lead gave a mean
absorbance of 0.200 with a relative standard deviation of 1.5 %. The sensitivity for 1 % absorption was 88 ng ml–1. The interference of a large number of anions and cations was studied
and the optimized conditions developed were utilized for the trace determination of lead in various standard samples.
An atomic absorption spectrometric method for the determination of trace amounts of lead after
adsorption of its 1-(2-pyridylazo)-2-naphthol (PAN) complex on microcrystalline naphthalene
has been developed. This complex was adsorbed on microcrystalline naphthalene in the
pH range 8.4–11.5 from large volumes of aqueous solutions of various alloys and biological
samples. After filtration, the solid mass consisting of the complex and naphthalene was dissolved
with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption
spectrometry. Lead was alternatively quantitatively adsorbed on 1-(2-pyridylazo)-2-naphthol-naphthalene adsorbent packed in a column and determined similarly. In this case, 0.5 g of lead was concentrated in a column from 500 ml of aqueous sample, where its concentration
was as low as 1.0 ng ml–1. Eight replicate determinations of 4.0 g ml–1 of lead gave a mean
absorbance of 0.200 with a relative standard deviation of 1.5 %. The sensitivity for 1 % absorption was 88 ng ml–1. The interference of a large number of anions and cations was studied
and the optimized conditions developed were utilized for the trace determination of lead in various standard samples.
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