Extraction-Spectrophotometric Determination of Trace Amounts of Iron (Iii) As Fecl4-Methylene Blue Ion-Pair in Saturated Nacl Solution

H. Parham*, N. Pourreza* and M. Naji

Department of Chemistry, Faculty of Science, Chamran University, Ahvaz (Iran)

A simple and sensitive extraction-spectrophotometric method for the determination of ferric ion in saturated salt media is reported. The FeCl4- -MB+ ion pair is quantitatively extracted into methyl isobutyl ketone (MIBK) and its absorption was measured at 658 nm. The FeCl4- anionic complex is formed in a saturated solution of sodium chloride which was 0.5M with respect to HCl. The calibration graph is linear over the iron (III) concentration range of 0.050-2.00 μg ml-1 and the regression coefficient is 0.998. The relative standard deviation (RSD) of ten replicate determination of 1 μg ml-1 of iron (III) is 1.5% and the limit of detection of the method is 0.03 μg ml-1. The method is successfully applied to the determination of total amount of iron in a standard aluminium base alloy.

Extraction; Determination; Ion pair; Ferric ion; Methylene blue