title: The use of on-line UV photoreduction in the flow analysis determination of dissolved reactive phosphate in natural waters.
abstract: A highly sensitive flow analysis manifold for rapid determination of dissolved reactive phosphate was developed which uses ethanol and UV light to reduce phosphomolybdic acid, instead of the reactive and short-lived chemical reductants typically employed in molybdenum blue chemistry. This reaction is impractical to perform reproducibly in batch mode, yet is very simple to handle in a flow analysis system and uses a single, very long-lived reagent solution. Interference from common inorganic anions and organic phosphorus species was minimal, and good spike recoveries for a range of sample matrices were obtained. The proposed flow analysis system is characterised by a limit of detection of 1.3 μg L(-1) P, linear range of 5-1000 μg L(-1) P, dynamic range of 5-5000 μg L(-1) P, repeatability of 0.8% (1000 μg L(-1) P, n=10) and 5.6% (10 μg L(-1) P, n=10), and sample throughput of 57 h(-1). It is expected that this method will improve the feasibility of autonomous long-term environmental monitoring of dissolved reactive phosphate using inexpensive apparatus.
authors.affiliation: 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.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Nagul
authors.affiliation: School of Chemistry, The University of Melbourne, Victoria 3010, Australia; School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL48AA, UK.
authors.forename: Ian D
authors.initials: ID
authors.lastname: McKelvie
authors.affiliation: 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.
authors.forename: Spas D
authors.initials: SD
authors.lastname: Kolev
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D017022:Flow Injection Analysis / Q000379:methods; D057230:Limit of Detection; D008982:Molybdenum / Q000737:chemistry; D010084:Oxidation-Reduction; D010710:Phosphates / Q000032:analysis*; D012995:Solubility; D014466:Ultraviolet Rays; D014867:Water / Q000032:analysis*
chemical_list: D010710:Phosphates; D014867:Water; C017541:molybdenum blue; D008982:Molybdenum
keywords: Dissolved reactive phosphate; Flow analysis; Molybdenum blue reaction; UV photoreduction