Japanese Source

Abstract

A new method for the measurement of orthophosphate in land water has been developed. Molybdophosphate, formed between orthophosphate and molybdate in a sulphuric acid solution, was extracted into 4-methyl-2-pentanone with a tri-n-propylammonium ion as a counter-ion. After evaporation of the solvent, the residue was dissolved with acetonitrile. An aliquot of this solution was injected into a FIA system. Tri-n-propylamine was measured with Ru(bpy)33+ chemiluminescence detection. The calibration curve for standard phosphate was linear in the range 0.0110 μM, and the detection limit was 7.3 nM (S/N= 3). Orthophosphate in real samples, such as river and mineral water, was successfully determined using the present method. © 2009 The Japan Society for Analytical Chemistry.