Flow-injection fluorimetric determination of mercury(II) with calcein.

A flow-injection spectrofluorimetric method for the determination of Hg(II) is described. The method is based on the complex that is formed between Hg(II) and calcein at pH 11-12. This reagent was not used before for determining Hg(II). The excitation wavelength is 324 nm and the emission wavelength is 522 nm. The calibration graph shows a linear range between 7.7 and 128 microg l(-1) (relative standard deviation 2.0%), the sampling rate was 90 h(-1). The effect of several interferents has been examined. Trace mercury in natural waters were determined satisfactorily using a modified manifold, which has an EDTA stream in order to minimize the calcium and magnesium interference.