Analytical Sciences

Flow Injection Determination of Iron Ions with Green Tea Extracts as a Natural Chromogenic Reagent

Piyanut PINYOU, Supaporn KRADTAP HARTWELL, Jaroon JAKMUNEE, Somchai LAPANANTNOPPAKHUN, and Kate GRUDPAN

Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand

A green chemistry system that utilizes natural extract as an alternative reagent for determination of metal ions has been investigated. The extract of green tea, a common beverage, is used for quantification of iron. The green tea extract was prepared in acetate buffer pH 4.8 and could be used without further purification with a simple flow injection (FI) system. The intensity of iron-green tea extract complexes was monitored using a green LED photometer. The use of natural reagent combined with the simple FI-LED photometer set up offers an alternative low cost and rapid system for the determination of metal ions. Detection limit of 0.05 ppm of Fe(III) ion and sampling rate of 180 injections h⁻¹ were achieved. Application of this system to the analysis of iron in pharmaceutical samples was demonstrated, and the results agreed well with those from the AOAC method.

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