Determination of trace amounts of phosphorus by laser excited time-resolved fluorimetry

Abstract

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 µg ml^–1. Samples were also taken from bovine serum albumin (containing 130 µg ml^–1 of phosphorus); the relative standard deviation was less than 5%(n= 10) and the detection limit was 0.7 ng ml^–1.