Liquid Chromatographic Determination of Urea in Water-Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions: Collaborative Study
| Autor: | George W Latimer, J Hartshorn, Dean Abrams, S. Pleasants, R. Sensmeier, K. Riter, G Schmunck, J Balthrop, G Volgas, Smith, S Herald, J Padmore, Michael Massoud Hojjatie, R Roser, Thomas M Parham, Dickinson, L Taylor, R Beine |
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| Rok vydání: | 2004 |
| Předmět: |
Pharmacology
Chromatography Aqueous solution Urea-formaldehyde Formaldehyde chemistry.chemical_element engineering.material Nitrogen Analytical Chemistry chemistry.chemical_compound chemistry Urea engineering Environmental Chemistry Amine gas treating Fertilizer Acetonitrile Agronomy and Crop Science Food Science |
| Zdroj: | Journal of AOAC INTERNATIONAL. 87:346-351 |
| ISSN: | 1944-7922 1060-3271 |
| Popis: | Water soluble urea-formaldehyde (UF) fertilizers, manufactured by complex reaction of urea and form-aldehyde, typically contain varying amounts of unreacted urea. A liquid chromatography method for the analysis of urea in these products, and in aqueous urea solutions, was collaboratively studied. An amine chromatography column was used to separate the unreacted urea from numerous UF reaction products present in these liquid fertilizers. Unreacted urea was determined by using external urea standards with UV detection at 195 nm. The standards and test samples were prepared in the mobile phase of 85% (v/v) acetonitrile in water. Ten laboratories analyzed 5 different UF-based commercial products containing unreacted urea in the range of 6 to 17% by weight, and 5 different concentrations of urea in water equivalent to commercial products of that nature. The aqueous urea solutions contained 2–20% urea (w/w). The range of sR values for the 5 UF-based commercial fertilizers was 0.49–1.02 and the %RSDR was 1.94–6.14. The sR range for the 5 urea solutions was 0.10 to 0.79 and the %RSDR range was 2.54 to 4.88. The average recovery of urea from the aqueous urea solutions was 96–103%. Therefore, this method is capable of monitoring urea nitrogen manufacturers' label claims and total nitrogen claims in those cases where urea is the sole source of plant food nitrogen. Based on the collaborative study data, the authors recommend this method be approved for AOAC Official First Action status. |
| Databáze: | OpenAIRE |
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