Spectral study of the interaction between 2-pyridinecarbaldehyde-p-phenyldihydrazone and ferric iron and its analytical application

The synthesis and spectral characterization of a schiff base, 2-pyridinecarbaldehyde-p-phenylenedihydrazone (short for 2PC-PPH), were described. It was found that ferric ion (Fe3+) could selectively quench the fluorescence of 2PC-PPH, whereas many other metal ions, such as Mn2+, Zn2+, Cu2+, K+, Al3+, Ca2+, Ni2+, Co2+, Cr3+ and Fe2+, could not quench its fluorescence. Based on this, a sensitive method for ferric ion selective detection was established. Under the optimum conditions, the decreasing fluorescence intensity of 2PC-PPH is proportional to the concentration of Fe3+ within the range of 6.0 × 10−7–1.0 × 10−5 mol L−1. The detection limit (3σ) for Fe3+ determination is 3.6 × 10−7 mol L−1. The proposed method was successfully applied to determine iron in tea and milk powder.

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► The interaction between Fe3+ and a schiff base was studied by spectroscopy.
► Ferric ion could selectively quench the fluorescence of it.
► A sensitive method for ferric ion selective detection was established.