DETERMINATION OF TRACE AMOUNTS OF PHOSPHORUS BY LASER-EXCITED TIME-RESOLVED FLUOROMETRY

Phosphorus was determined as orthophosphate via formation of the phosphorus-vanadium-molybdenum heteropoly acid ion-association complex with lactic acid-6,9-diamino-2-ethoxyacridine (livanol). The extraction-flotation method was used to separate and concentrate the complex, after which laser-excited time-resolved fluorimetry was employed to determine phosphorus in samples of water, plants, organisms, soils and rocks. The method showed good linearity over the phosphorus concentration range 0-0.5 mug ml-1. Samples were also taken from bovine serum albumin (containing 130 mug ml-1 of phosphorus); the relative standard deviation was less than 5% (n = 10) and the detection limit was 0.7 ng ml-1.