Determining total phosphorus in water with method of flow injection

When we used Lachat QC8500 three-channel flow injection analyzer,we made different forms of phosphorus changed into phosphate by method of ultraviolet digestion with potassium peroxy disulfate.Orthophosphate and ammonium molybdate generated phosphorus molybdenum compound with reaction of antimony potassium tartrate.Phosphorus molybdenum compound was restored by ascorbic acid into blue compounds,which are absorbed at 880nm.The detection limit of the equipment was 0.0012mg/L.The linear range was 0.05~1mg/L(r0.999)and recover rate of standard addition is 95.0%~104%.Compared with method of ammonium molybdate spectrophotography in GB11893-89,the result had not significant difference.Test result shows that the method is simple,fast,accurate and applicable to determine total phosphorus in water.