Altemar da Cruz Luciano, Adriana Costa Ferreira, Geovani Cardoso Brandão, Fábio de Souza Dias, Erik Galvão Paranhos da Silva, Walter Nei Lopes Dos Santos, Liz Oliveira Dos Santos
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引用次数: 0
Abstract
Background: Certified reference materials (CRMs) are essential for method validation, quality control, and metrological traceability in analytical chemistry. However, CRMs for plant matrices of regional relevance, such as castor bean (Ricinus communis L.) leaves, remain scarce in tropical and subtropical regions. This study addresses that gap by evaluating the homogeneity of a castor bean leaf RM candidate produced under single-laboratory conditions.
Objective: To assess between- and within-unit homogeneity of a Ricinus communis L. leaf RM candidate for seven inorganic elements (Al, Ca, Cu, Fe, Mg, P and Zn), following ISO Guide 35:2017. This study does not aim at certification or replacement of full certification procedures as specified in ISO 17034:2016.
Methods: Castor bean leaf samples were collected in Bahia, Brazil. A total of 400 g of dry material was produced, homogenized, and distributed among 20 units. Elemental mass fractions were determined by microwave-induced plasma optical emission spectrometry (MIP OES) after acid digestion. Data were evaluated by one-way ANOVA (ISO Guide 35:2017) and principal component analysis (PCA) as a complementary exploratory tool.
Results: A minimum sample mass of 400 mg was established as adequate for reliable homogeneity evaluation. Ten units were randomly selected for between-bottle assessment, with three subsamples per unit for within-bottle evaluation.
Conclusion: The RM candidate was considered homogeneous for all seven elements at the 95% confidence level. PCA provided additional exploratory insights, including identification of atypical subsamples not detectable by univariate ANOVA.
Highlights: Castor bean RM will be of great use for confirming the accuracy of methods, which will facilitate the validation of analytical methods and verification of quality control of samples of vegetable leaves or similar matrix, in addition to allowing metrological traceability.
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