Flame Atomic Absorption Spectrometric Determination of Trace Lead after Solid-Liquid Extraction and Preconcentration Using 1-(2-Pyridylazo)-2-naphthol

Sa？etak 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 μg 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 μg 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