Continuous flow analysis of phosphate in natural waters using hydrazine asa reductant

Citation
Jz. Zhang et al., Continuous flow analysis of phosphate in natural waters using hydrazine asa reductant, INT J ENV A, 80(1), 2001, pp. 61-73
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
ISSN journal
0306-7319 → ACNP
Volume
80
Issue
1
Year of publication
2001
Pages
61 - 73
Database
ISI
SICI code
0306-7319(2001)80:1<61:CFAOPI>2.0.ZU;2-E
Abstract
The use of hydrazine to reduce 12-molybdophosphoric acid to phosphomolybden um blue in continuous flow analysis of phosphate in natural water samples i s characterized. Using hydrazine in gas-segmented continuous flow phosphate analysis minimizes coating and silicate interference in comparison with us ing ascorbic acid. The addition of Sb to the molybdate reagent increases se nsitivity at temperatures greater than 50 degreesC but causes severe additi onal coating. The degree of coating was found to be a function of pH. Minim al coatings were achieved at a final solution pH of 0.5. Silicate interfere nce was found to increase dramatically with color development temperature. At room temperature no detectable silicate interference was found. We recom mend hydrazine in preference to ascorbic acid for gas-segmented continuous flow phosphate analysis with optimal reaction conditions of room temperatur e color development and a final solution pH of 0.5.