Determination of ethylenediaminetetraacetic acid base on the reversion of fluorescence quenching of 2-pyridinecarbaldehyde-p-phenyldihydrazone by ferric iron.

A fast and sensitive fluorometric method for determination of an emerging pollutant, ethylenediaminetetraacetic acid (EDTA), was proposed based on the reversion of fluorescence quenching of 2-pyridinecarbaldehyde-p-phenyldihydrazone by ferric iron. It was found that Fe(3+) could selectively quench the fluorescence of 2PC-PPH, while EDTA could recover it due to its strong coordination ability with Fe(3+). Based on this, we established an "Off and On" fluorescence method for determination of EDTA. Under the optimum conditions, the linear range and detection limit (3S/N) for EDTA determination were 2.0 × 10(-6)~1.4 × 10(-5) mol L(-1) and 1.5 × 10(-7) mol L(-1), respectively. The relative standard deviation for the determination of 7.0 × 10(-6)mol L(-1) EDTA was 3.7% (n=11). The method was successfully applied to determination of EDTA in tap water, lake water and investigating degradation of EDTA by TiO2/UV process.