On-line rapid determination of phosphate in seawater

A new method of the compact,rapid and direct detection of trace phosphate in seawater was described by flow injection spectrophotometry with Molybdophosphate and malachite green.Under the optimal conditions,the system exhibited the detection limit of 0.29 μg/L,reproducibility of 0.76 % RSD for 50μg/L phosphate ion added in seawater(n=8) and the linear response y=1.2243x+3.4529(R2=0.9995).When calibrated in the field with standards in the range 1 ～ 50 μg/L.The results were satisfied using this method to analyze the phosphate in seawater,and the range of recovery percentages was from 91.9 to 108.2 %.The FIA system was evaluated for the determination of phosphate in monitoring station,survey boat and laboratory.