Liquid Chromatography – Catalytic Analysis Detection as a Highly Sensitive and Automated Fractional Determination Method: Determination of Iron(II) and (III)

Abstract

Liquid chromatographic separation and catalytic analysis detection was investigated for automated fractional determination of iron(II) and (III). Chromatographic separation between these species was performed with a deoxygenated mixed solution (pH 3.5) of ethylenediamine and citric acid as the eluent and a separation column containing sulphonate groups. The eluent was introduced to an air segmented continuous flow analysis based on the catalytic reaction with Bindschedler's green leuco base. The detection limits of this method for iron(II) and (III) were 8.2 nmol dm⁻³ and 1.7 × 10² nmol dm⁻³, respectively. This method was applied to the analysis of lake and pore waters.

Keywords:

• 4,4′-bis(dimethylamino)diphenylamine
• Air segmented continuous flow analysis
• Catalytic analysis detection
• HPLC
• Iron

ACKNOWLEDGMENTS

The authors thank Mr. K. Nishimura BL Tech, Japan, for his fruitful comments on the construction of the catalytic analysis system with an autoanalyzer. The authors are also indebted to Mr. T. Koitabashi and T. Miyano, Center for Ecological Research, Kyoto University, for their kind cooperation in the collection of lake water and sediments. This research was partly supported by a grant from Shimadzu Science Foundation.

Notes

All samples were collected in March, 2004. AAS: Atomic absorption spectrometry. ND: Not detectable.

^a Depth from the sediment surface.