title: Homogeneity study of a corn flour laboratory reference material candidate for inorganic analysis.
abstract: In this work, a homogeneity study of a corn flour reference material candidate for inorganic analysis is presented. Seven kilograms of corn flour were used to prepare the material, which was distributed among 100 bottles. The elements Ca, K, Mg, P, Zn, Cu, Fe, Mn and Mo were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) after acid digestion procedure. The method accuracy was confirmed by analyzing the rice flour certified reference material, NIST 1568a. All results were evaluated by analysis of variance (ANOVA) and principal component analysis (PCA). In the study, a sample mass of 400mg was established as the minimum mass required for analysis, according to the PCA. The between-bottle test was performed by analyzing 9 bottles of the material. Subsamples of a single bottle were analyzed for the within-bottle test. No significant differences were observed for the results obtained through the application of both statistical methods. This fact demonstrates that the material is homogeneous for use as a laboratory reference material.
authors.affiliation: Universidade Federal da Bahia, Instituto de Química, Grupo de Pesquisa em Química e Quimiometria, Campus Ondina, 41170-115 Salvador, Bahia, Brazil. Electronic address: amps@ufba.br.
authors.forename: Ana Maria Pinto
authors.initials: AM
authors.lastname: Dos Santos
authors.affiliation: Universidade Federal da Bahia, Instituto de Química, Grupo de Pesquisa em Química e Quimiometria, Campus Ondina, 41170-115 Salvador, Bahia, Brazil.
authors.forename: Liz Oliveira
authors.initials: LO
authors.lastname: Dos Santos
authors.affiliation: Universidade Federal da Bahia, Instituto de Química, Grupo de Pesquisa em Química e Quimiometria, Campus Ondina, 41170-115 Salvador, Bahia, Brazil.
authors.forename: Geovani Cardoso
authors.initials: GC
authors.lastname: Brandao
authors.affiliation: Universidade Federal da Bahia, Instituto de Química, Grupo de Pesquisa em Química e Quimiometria, Campus Ondina, 41170-115 Salvador, Bahia, Brazil.
authors.forename: Danilo Junqueira
authors.initials: DJ
authors.lastname: Leao
authors.affiliation: Universidade Federal Fluminense, Centro de Estudos Gerais, Instituto de Química, Niterói, Rio de Janeiro, Brazil.
authors.forename: Alfredo Victor Bellido
authors.initials: AV
authors.lastname: Bernedo
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto Alberto Luiz Coimbra de Pós Graduação e Pesquisa de Engenharia, Programa de Engenharia Nuclear, Rio de Janeiro, Brazil.
authors.forename: Ricardo Tadeu
authors.initials: RT
authors.lastname: Lopes
authors.affiliation: Universidade Estadual do Sudoeste da Bahia, Laboratório de Química Analítica (LQA), Campus de Jequié, 45206-190 Jequié, Bahia, Brazil.
authors.forename: Valfredo Azevedo
authors.initials: VA
authors.lastname: Lemos
mesh_terms: D002118:Calcium / Q000032:analysis; D005433:Flour / Q000032:analysis*; D007753:Laboratories / Q000592:standards*; D013058:Mass Spectrometry / Q000379:methods / Q000592:standards*; D008970:Molecular Weight; D012275:Oryza / Q000737:chemistry; D012015:Reference Standards; D003313:Zea mays / Q000737:chemistry*
chemical_list: D002118:Calcium
keywords: Analysis of variance; Corn flour; Homogeneity study; Principal component analysis; Reference material candidate