Fluorescence properties of some schiff's bases derived from 3-hydroxypyridine-2-aldehyde and of their metal chelates Fluorimetric determination of manganese based on its catalytic effect on the oxidation of these compounds with hydrogen peroxide.

The fluorimetric properties of the oxime, thiosemicarbazone, azine and 2-pyridylhydrazone of 3-hydroxypyridine-2-aldehyde have been studied; quantum yields have been measured in ethanol-water and ethanol-dimethylformamide media. Two kinetic methods are described for the determination of trace amounts of manganese(II), based on its catalytic effect on the oxidation of the thiosemicarbazone and of the azine by hydrogen peroxide. The reactions are followed by measuring the rate of change of the fluorescence. The calibration graph is linear over the manganese range 5-50 ng ml with a precision of +/- 3.0% for the thiosemicarbazone, and 0.4-0.9 mug ml with a precision of +/-2.0% for the azine. Interferences by foreign ions have been investigated.