Rapid, sensitive and selective spectrophotometric determination of phosphate as an ion associate of 12-molybdophosphate with Astra Phloxine

• Published in: Mikrochimica acta (1966) Vol. 159; no. 3-4; pp. 371 - 378
• Main Authors: VISHNIKIN, Andriy B, AL-SHWAIYAT, Mohammed Khair E. A, BAZEL, Yaroslav R, ANDRUCH, Vasil
• Format: Journal Article
• Language: English
• Published: Wien Springer 01-07-2007; New York, NY
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Spectrometric and optical methods; Phosphates; Phosphate determination; Absorption spectrometry; ion associate; Molybdophosphates; Standard curve; Astra Phloxine; Absorption coefficient; Polymethine dye; Surfactant; Spectrophotometry; Seawater
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-007-0754-7

A highly sensitive and selective reaction of 12-molybdophosphate with the polymethine dye Astra Phloxine has been used for the spectrophotometric determination of phosphate. If the concentration of phosphate is less than 1mumolL, supersaturated solutions of ion associate (IA) are stable without the use of a surfactant. Under these conditions, a new band appears in the absorption spectrum at 574nm. The color of the IA develops immediately after mixing of reagents and remains constant over several hours. The molar absorptivity of the IA is 1.54 X 10Lmolcm. The calibration graph is linear between 0.02 and 0.8mumolL of phosphate. The limit of detection is 7nmolL. Phosphate was determined in pure chemicals and water samples, including Dead Sea water.