Application of the Ion Pair of 1,10-Phenanthroline and Tetraphenylborate for Preconcentrartion of Trace Iron and Determinatio by Derivative Spectrophotometry

摘要

Iron is quantitatively retained on 1,10-phenanthroline-teraphenylborate with microcrystalline naphthalene or by a column method in the pH range 1.5 -6.0 from a large volume of aqueous solutions of various standard alloys and biological samples. After filtration, the solid mass consisting of the iron complex and naphthalene was dissolved in 5 mL of dimethylformamide and the metal was determined by third derivative spectrophotometry. Iron complex can alternatively be quantitatively adsorbed on ammonium tetraphenylboratenaphthalene adsorbent packed in a column and determined similarly. The detection limit is 30 mg mL~(-1) (signal to noise ratio=2) and the calibration curve is linear in th range 0.05-8 #mu#g mL~(-1) in dimethylformide solution with a correlation coefficient of 0.9996 . Eight replicated determination of 6 #mu#g of iron in 5 mL dimethylformamide solution gave a mean intensity ( peak to peak between #lambda#_3 and #lambda#_2) of 0.618 with a relative standard deviation of 0.99% . 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 iron in various standard alloys and biological samples.