Analytical Sciences

Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Manganese in Alloys and Biological Samples after Preconcentration with the Ion Pair of 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol and Ammonium Tetraphenylborate on Microcrystalline Naphthalene or by Column Method

Mohammad Ali TAHER

Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran

Manganese is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 7.5 - 10.5 from large volumes of aqueous solutions of various samples. After filtration, each solid mass consisting of the manganese complex and naphthalene was dissolved with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption spectrometry. Manganese complex can alternatively be quantitatively adsorbed on ammonium tetrphenylborate-naphthalene adsorbent packed in a column and determined similarly. About 0.1 ug of manganese can be concentrated in a column from 500 ml of aqueous sample, where its concentration is as low as 0.2 ppb. Eight replicate determinations of 1.0 ppm of manganese gave a mean absorbance of 0.224 with a relative standard deviation of 1.8%. The sensitivity for 1% absorption was 19 ppb. 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 manganese in various standard samples.

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