title: Determination of ortho- and pyrophosphates in waters by extraction chromatography and flow-injection analysis.
abstract: Extraction-chromatographic separation of ortho- and pyrophosphate anions on an inert support modified with an organotin extractant was studied and used for their subsequent determination in a flow-injection system. The proposed FIA manifold includes an extraction-chromatographic mini-column, on which the phosphate anions are separated and preconcentrated, and a post-column spectrophotometric detector. For the determination of orthophosphate, the absorbance of the reduced 12-molybdophosphoric acid is monitored at 660 nm. The sum of ortho- and pyrophosphate can be determined after preliminary hydrolysis of pyrophosphate to orthophosphate in neutral solution at 50 degrees by use of inorganic pyrophosphatase. For a sample volume of 6 ml, the calibration graph is linear within a range of 5.0-100.0 ng/ml P. The limit of detection is 0.3 ng/ml P. The recovery of the ions to be determined is not less than 96%, the relative error is not worse than 4%. The proposed method was used for the analysis of river water samples.
authors.affiliation: Vernadsky Institute of Geochemistry and Analytical Chemistry, Academy of Sciences, V-334 Moscow, U.S.S.R.
authors.forename: B Y
authors.initials: BY
authors.lastname: Spivakov
authors.forename: T A
authors.initials: TA
authors.lastname: Maryutina
authors.forename: L K
authors.initials: LK
authors.lastname: Shpigun
authors.forename: V M
authors.initials: VM
authors.lastname: Shkinev
authors.forename: Y A
authors.initials: YA
authors.lastname: Zolotov
authors.forename: E
authors.initials: E
authors.lastname: Ruseva
authors.forename: I
authors.initials: I
authors.lastname: Havezov