A New Reagent Immobilization Method for a Portable Fiber Optic Probe for Determination of Ferrous Ions

Abstract

An absorbance-based optic fiber probe for determination of ferrous ions is described. It is based on 4,7-diphenyl-1,10-phenanthroline as a sensitive reagent which was immobilized on polymethylmethacrylate (PMMA) using a new immobilization method. The proposed probe responded linearly to the Fe²⁺ concentration in the range of 0.03 - 1.0 mg l^-1. The response time required to reach a stable signal was short (less than 10 min). The probe exhibited pH and temperature independence, small ion interference, good selectivity, reproducibility and stability. It was applied for direct analysis of Fe²⁺ ions in natural water. The results were comparable to those obtained by a conventional spectrophotometric method. The results of recovery tests were also satisfactory.