DETERMINATION OF ORTHOPHOSPHATE IN WATERS AND SOILS USING A FLOW ANALYZER

A high-performance continuous flow analyser has been used for the determination of orthophosphate ion in potable waters and soil extracts by the heteropolymolybdenum blue method. Interference from a number of common ionic species has been examined and found to be small at the levels encountered in potable waters. The limit of detection for PO43- was calculated to be 14.5 p.p. b. (4.8 p.p.b. of P), a linear calibration range of up to 0-100 p.p.m. was demonstrated and the sample throughput was better than 120 samples h~1 using the calibration range 0-4 p.p.m. and above, and 50 samples h~1 using the range 0-0.5 p.p.m.