Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Thallium after Solid-Liquid Extraction and Preconcentration with Use of 1,10-Phenanthroline onto Benzophenone

Thallium is quantitatively retained by 1,10-phenanthroline and tetraphenylborate onto benzophenone in the pH range 0-11 from a large volumes of aqueous solutions of various samples. After filtration, the solid mass consisting of thallium complex and benzophenone is dissolved with 5 mL of dimethylformamide and the metal was determined by flame atomic absorption spectrometric. About 0.4 µg of thallium can be concentrated from 400 mL of aqueous sample, where its concentration is as low as 1.0 ng/mL. Eight replicate determinations of 8.0 µg/mL of thallium in final dimethylformamide solution gave a mean absorbance of 0.160 with a relative standard deviation of 1.7%. The sensitivity for 1 % absorption was 0.22 µg/mL. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of thallium in various alloys and biological samples