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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Preparation and characterization of phosphate rock as quality control material

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da Silva, Caroline Santos [1, 2] ; de Souza, Gilberto Batista [2] ; Araujo Nogueira, Ana Rita [2]
Total Authors: 3
[1] Univ Fed Sao Carlos, Dept Chem, Grp Appl Instrumental Anal, POB 676, BR-13560970 Sao Carlos, SP - Brazil
[2] Embrapa Pecuaria Sudeste, POB 339, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: ACCREDITATION AND QUALITY ASSURANCE; v. 23, n. 1, p. 39-45, FEB 2018.
Web of Science Citations: 0

A quality control material for inorganic constituents present in a phosphate-bearing rock used to manufacture phosphate fertilizers was produced and characterized according to the ISO Guide 80. The evaluation of the estimated minimum mass, homogeneity, and stability of the material was performed using microwave-assisted digestion and inductively coupled plasma optical emission spectrometry (ICP-OES) as an in-house validated technique for determination of Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, V, and Zn. Phosphorus mass fraction determination was done by laser-induced breakdown spectroscopy. The accuracy of the measurement results was confirmed by analyzing the certified phosphate rock and fertilizer certified reference materials according to NIST SRM 694 and SRM 695. One-way analysis of variance (ANOVA) was applied to the measurement data, and the homogeneity and stability of the material presented averages within the 95 % confidence interval. The results from the preparation and with collaborative trial allowed the calculation and estimation of the consensus value and its expanded measurement uncertainties, obtained by combining the uncertainty contributions from characterization (u (char)), between-bottle homogeneity (u (bb)), short-term stability (u (sts)), and long-term stability (u (lts)) for each evaluated analyte mass fraction. (AU)

FAPESP's process: 15/14488-0 - Analytical method development for quality determination of fertilizers and tanning waste
Grantee:Ana Rita de Araujo Nogueira
Support type: Regular Research Grants