Indirect atomic-absorption spectrophotometric determination of phosphorus after flotation as the ion-pair of molybdophosphate with bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III)

An atomic-absorption spectrophotometric method has been developed for the indirect determination of phosphorus. The calibration graph is linear over the range 0.025-0.2 mug of phosphorus. The relative standard deviation is 1.3% for 0.2 mug of phosphorus (6 replicates). The method has been applied to the determination of phosphate in natural water samples. The enhancement effect of acetone on the determination is discussed.