IJUP08 - Universidade do Porto

Automatic FIA method for determination of iron in environmental
samples
E. P. Freitas, F. A. Dias, H. M. Oliveira, M. A. Segundo, S. Reis and J. L. F. C. Lima
REQUIMTE, Serviço de Química-Física, Faculdade de Farmácia, Universidade do Porto,
Rua Aníbal Cunha, 164, 4099-030, Porto, Portugal
Email: elisa_10_10@hotmail.com; pipa_angel@hotmail.com
Iron is a ubiquitous element in the environment, especially abundant in rocks and soil. In
its biogeochemical cycle [1], iron is absorbed by plants as it is an essential element for its
growth and survival. In animals, iron is acquired through their diet. It is essential for their
metabolism, sustaining the effectiveness of hemoglobin. When these organisms die, the
microbial decomposers will break down essential nutrients from the body, including iron,
back to the soil. The presence of iron in different environmental matrices and its important
role upon life demands its quantification, namely in studies concerning its bioavailability,
toxicity and mobility.
In this context, the automation of the determination of iron is essential. Flow Injection
Analysis (FIA) [2] is an automation technique based on three principles: (1) reproducible
sample injection in a flowing carrier stream, (2) controlled dispersion of the sample zone
and (3) reproducible timing of its movement from the injector point to the detection
system. These principles allowed determination without need of physical or chemical
equilibrium.
The aim of this work is to provide a FIA system for the spectrophotometric determination
of iron in environmental samples (water, soil, etc). The development of the flow method
will comprise several steps, including the selection of the chromogenic reagent, the
optimization of reaction conditions (reagent concentration, time), and the optimization of
the manifold configuration (sample volume, flow rate, reaction coil length). Finally, the
accuracy and the precision of the novel methodology will be assessed through application
to real samples.
References:
[1] Shaked, Y., Erel, Y., and Sukenik, A. (2004), The biogeochemical cycle of iron and associated
elements in Lake Kinneret, Geochimica et Cosmochimica Acta, 68 (7), 1439-1451.
[2] Ruzicka, J., and Hansen, E.H. (1975), Flow injection analyses. 1. New concept of fast
continuous flow analysis, Analytica Chimica Acta, 78 (1), 145-157.
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