The determination of trace amounts of phosphate in natural water by flow injection fluorimetry

Abstract A new method is suggested for the determination of trace amounts of phosphate by flow injection fluorimetry, based on the principle that molybdophosphate could quench the fluorescence of Rhodamine 6G. The fluorescence is excited at 350 nm and measured at 550 nm. The calibration graph is linear up to 100 ng/ml phosphorus concentration and the detection Unit is 1.9 ng/ml. The present method has been applied to the determination of soluble phosphorus in natural water samples, the recoveries were in the range of 92 – 102 %. The sampling rate is 120 samples per hour.