Trace Analysis of Phosphorus in Water by Sorption Preconcentration and Luminol Chemiluminescence

Abstract

A new, highly sensitive chemiluminescence method for the determination of sub-ppb quantities of phosphorus in water is described. The method is based on sorption preconcentration of phosphorus as a yellow vanadomolybdophosphoric heteropoly acid (HPA) in the presence or absence of a cationic surfactant on a paper filter, followed by direct chemiluminescence detection of the phosphorus concentrate via reaction with an alkaline luminol solution. The molar ratio of cationic surfactant to HPA in the ion associate sorbed on the filter is 4:1. The detection limits for phosphorus are 0.02 microgram of P L-1 in the presence of surfactant and 0.1 microgram of P L-1 in the absence of surfactant for a sample volume of 150 mL. The calibration plot is linear from 0.06 to 1.7 micrograms of P L-1 in the presence of a surfactant, and the time required for analysis is 25 min. In the absence of surfactant, the selectivities against Si4+ and As5+ are 5 and 40 times greater than those for the standard colorimetric method based on the formation of the blue molybdophosphoric HPA. Applications of the method to the analyses of river water, seawater, and the turbine vapor condensate from a coal-fired power plant are described. It is demonstrated that the sensitivity advantage of the chemiluminescence technique can be combined with the magnesium-induced coprecipitation (MAGIC) method for a more selective measurement of soluble reactive phosphorus.

Dynamics of Dissolved Organic Phosphorus

“…This method has been used to reliably detect subnanomolar concentrations of Pi in seawater (Wu et al, 2000). MAGIC has also been combined with a novel luminol chemiluminescence technique to provide a convenient, alternative subnanomolar Pi detection system (Zui and Birks, 2000).…”

Analysis of Pesticides by Flow Injection Coupled with Chemiluminescent Detection: A Review

“…It was based on the fact that organophosphorus pesticides can be decomposed into orthophosphate with potassium peroxodisulphate as oxidant under ultraviolet radiation (Pérez-Ruiz 2001). The produced orthophosphate can react with molybdate and vanadate to form the vanadomolybdophosphoric heteropoly acid which can oxidize luminol to produce intense CL emission (Zui 2000). The decomposing kinetic characteristics of these pesticides are different and strongly dependant on their molecular structure.…”

Laser-Heating Thermal Modulation Voltammetric Determination of Phosphate Ion Using a Graphite-Reinforced Carbon Electrode

“…23,24 The determination of nanomolar concentrations of phosphate ion based on luminol chemiluminescence has also been reported. 25,26 A highly sensitive HPLC method for the detection of phosphate ion has been published. 27 Now, in this work, TM voltammetry has been utilized in the determination of phosphate ion with its good sensitivity and stability.…”