The molybdenum blue reaction for the determination of orthophosphate revisited: Opening the black box

Edward A Nagul; Ian D McKelvie; Paul Worsfold; Spas D Kolev

doi:10.1016/j.aca.2015.07.030

The molybdenum blue reaction for the determination of orthophosphate revisited: Opening the black box

Anal Chim Acta. 2015 Aug 26:890:60-82. doi: 10.1016/j.aca.2015.07.030. Epub 2015 Aug 10.

Authors

Edward A Nagul¹, Ian D McKelvie², Paul Worsfold³, Spas D Kolev⁴

Affiliations

¹ School of Chemistry, The University of Melbourne, Victoria 3010, Australia; Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Victoria 3010, Australia.
² School of Chemistry, The University of Melbourne, Victoria 3010, Australia; School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL48AA, UK.
³ School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL48AA, UK.
⁴ School of Chemistry, The University of Melbourne, Victoria 3010, Australia; Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Victoria 3010, Australia. Electronic address: s.kolev@unimelb.edu.au.

PMID: 26347168
DOI: 10.1016/j.aca.2015.07.030

Abstract

The molybdenum blue reaction, used predominantly for the determination of orthophosphate in environmental waters, has been perpetually modified and re-optimised over the years, but this important reaction in analytical chemistry is usually treated as something of a 'black box' in the analytical literature. A large number of papers describe a wide variety of reaction conditions and apparently different products (as determined by UV-visible spectroscopy) but a discussion of the chemistry underlying this behaviour is often addressed superficially or not at all. This review aims to rationalise the findings of the many 'optimised' molybdenum blue methods in the literature, mainly for environmental waters, in terms of the underlying polyoxometallate chemistry and offers suggestions for the further enhancement of this time-honoured analytical reaction.

Keywords: Dissolved reactive phosphorus; Molybdenum blue reaction; Orthophosphate; Phosphomolybdate.

Publication types

Review