Fresenius' Zeitschrift für analytische Chemie

, Volume 334, Issue 1, pp 45–48 | Cite as

Determination of phosphate by flotation-fluorophotometry using ion-pair of molybdophosphate with Rhodamine 6G

  • Mitsuhiko Taga
  • Masahiko Kan
  • Toshiko Nasu
Original Papers Spectrofluorometric Analyses


A highly sensitive and accurate fluorophotometric method is described for the determination of phosphate using the ion pair formation of molybdophosphate with Rhodamine 6G. This ion pair is floated at the phase boundary between ethyl ether phase and aqueous phase when the aqueous phase is adjusted to 0.38 mol/l sulphuric acid, 1.9 mmol/l ammonium molybdate and 3.8 Μmol/l Rhodamine 6G. After the phase separation, the floated ion pair is dissolved into the ethyl ether phase by the addition of methanol. The fluorescence intensity of the ion pair is measured at 548 nm with excitation at 530 nm. The calibration curve for phosphate is linear up to 100 ng of phosphorus with a correlation coefficient of 0.999. The relative standard deviation is 2.3% for 100 ng of phosphorus (n=11). Although arsenic(V) causes a positive error, no ions commonly existing in natural water, including silicate, interfere with the determination of phosphate. The proposed method was applied to the determination of phosphate-phosphorus in some natural waters and satisfactory results were obtained.


Phosphorus Silicate Arsenic Aqueous Phase Phase Separation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Bestimmung von Phosphat durch Flotations-Fluorophotometrie mit Hilfe des Ionenpaares Molybdophosphat-Rhodamine 6G


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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Mitsuhiko Taga
    • 1
  • Masahiko Kan
    • 1
  • Toshiko Nasu
    • 2
  1. 1.Department of Chemistry, Faculty of ScienceHokkaido UniversitySapporoJapan
  2. 2.Chemistry Laboratory, Sapporo CollegeHokkaido University of EducationSapporoJapan

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