Enhancement of the fluorescence of the beryllium-morin complex by non-ionic surfactants

The effect of surfactants on the fluorescence of the beryllium-morin system has been studied. Non-ionic surfactants strongly enhance the fluorescence intensity of the beryllium complex. The addition of Triton X-100 makes possible the fluorimetric determination of submicrogram quantities of beryllium in feebly acidic media (pH 5.8-6.2, hexamine buffer). The fluorescence is excited at 440 nm and measured at 530 nm. The calibration graph is linear up to 10 ng/ml Be and the detection limit is 0.04 ng/ml. The relative standard deviation is 2.2% for beryllium at 0.5 ng/ml concentration and 0.7% for 5.0 ng/ml. The effects of 25 ions commonly found in water have also been studied; Zn(2+) and F(-) give the main interference. The method has been applied to the determination of beryllium in water pollution quality-control samples with satisfactory results.