Abstract
Iron is widely distributed in nature, which plays an important role in both biological and environmental media. Iron not only is an essential nutirent biologically, which is part of hemoglobin, the oxygen-carrying component of the blood; but also is related to carbon dioxide flux at air/sea interface. Due to its significance in the perspective of clinical diagnosis, intoxication, environmental pollution monitoring, many methods have been proposed for determination of iron species in natural samples. In this study, we demonstrated a new method involving the use of dopa and zinc ion in citric acid buffer (pH = 6), for selectively detecting ferrous ion by acquiring fluorescence produced from dopa oxidation. Metal ions, such as iron (ferric and ferrous ion), copper, and manganese are good candidates to accelerate the oxidation of catecholamines. In the presence of ferrous, dopa, and zinc ion, fluorescence signals were obtained, which could be detected at exciation wavelength of 370 nm and emission wavelength of 500 nm. A dose-dependent increase of fluorescence intensity was noted when the concentration of iron in the tested samples were elevated. The detection range of this system for ferrous ion falls between 1 μM and 100 μM, the detection limit (S/N = 3) is calculated as 1.23 μM.