Determination of total phosphorus in waters and wastewaters by on-line UV/thermal induced digestion and flow injection analysis

• Published in: Analytica chimica acta Vol. 326; no. 1; pp. 29 - 39
• Main Authors: Benson, Richard L., McKelvie, Ian D., Hart, Barry T., Truong, Yen B., Hamilton, Ian C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.06.1996; Elsevier
• Subjects: Analytical chemistry; Chemistry; Digestion; Exact sciences and technology; Filtration; Flow injection; Freshwater; General, instrumentation; Phosphate; Phosphorus; Spectrophotometry; Waters; Filtration; Phosphate; Phosphorus; Digestion; Spectrophotometry; Waters; Flow injection; Trace analysis; Water; Phosphates; Chemical analysis; On line; Thermal decomposition; Waste water; Ultraviolet irradiation; Detection limit; Photochemical degradation; Ultraviolet visible spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(96)00044-X

An on-line flow-injection system for the determination of total phosphorus in waters and wastewaters is described. Digestion was performed using a UV photoreactor and a thermal digestion unit connected in series. The orthophosphate formed was detected as phosphomolybdenum blue after on-line filtration. Reagent and digestion conditions required to give optimal oxidation and hydrolysis of organic and condensed model compounds are reported. The flow-injection method gave complete recovery for all the model organic P compounds tested, and >85% recovery for condensed phosphates. When the proposed method was applied to a series of wastewater samples, the results obtained were in close agreement with those from a conventional batch digestion method. The technique was rapid (8 samples h −1 4 replicates), with a linear range of interest for wastewaters 0–18 mgPl −1 and a detection limit of 0.15 mgPl −1.