Flame atomic absorption spectrometric determination of trace amounts of cobalt in standard aloys and biological samples after preconcentration of its 1,10-phenanthroline complex on tetraphenylbrorate-microcrystalline maphthalene adsorbent

摘要

A rapid,simple and sensitive method has been developed for determinatin of trace amount of cobalt using flame atomic absorption spectrometry,Cobalt is quantitatively retained as 1,10-phenanthroline-tetraphenylborate ion-associate complex on microcrystalline naphthalene in the pH range 2.6-9.5 from a large volume of its aqueous solutions of variousstandard alloys adn biological samples.After filtration,the solid mass consisting of the cobalt complex and naphthalene is dissolved in 5 mL of dimethylformamide (DMF)and the metal is determined using flame atomic absorption spectrometry by measuring the absorbance at 240.7 nm.Cobalt-1,10-phenanthroline complex and alternatively be quantitatively retained on ammonium tetraphenylborate-naphthalene adsorbent packed in a column at a flow rate of 2 mL/min under the same conditions and determined similarly.In this case,1.0 mug of cobalt is concentrated in a column from 400 mL of its aqueous sample,where its concentration is as low as 2.5 ppb.Eight reglicate determinations of 4.0 ppm cobalt gives a mean absorbancer of 0.120 with a relative standard deviation of 1.8%.The sensitivity for 1% absorption is 147 ppb.The conditions have been optimized and utilized for trace determination of cobalt in various standard samples.