Preparation of a reference material for crude oil trace elements: Study of homogeneity and stability

Marchezi, Thábita Thiciana Bastos; Vieira, Luiza Valli; Sena, Rodrigo Caciano de; Castro, Eustáquio Vinícius Ribeiro de; Brandão, Geisamanda Pedrini; Carneiro, Maria Tereza Weitzel Dias

doi:10.1016/j.microc.2020.104799

Cited by 6 publications

(2 citation statements)

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“…Statistical evaluation of the study results was also performed using linear regression analysis aims to identify any instability in the analyte in accordance with the ISO Guide 35 [9]. When there is no model that realistically describes the degradation mechanism of a reference material, a linear model is usually used as an empirical model [19]. In this model, the intercept (b 0 ) is expected to be equal to the value obtained in the characterization, while the slope (b 1 ) should not be significantly different from zero [19].…”

Section: Stability Assessment Of Crm 321 Long-term Stabilitymentioning

confidence: 99%

“…When there is no model that realistically describes the degradation mechanism of a reference material, a linear model is usually used as an empirical model [19]. In this model, the intercept (b 0 ) is expected to be equal to the value obtained in the characterization, while the slope (b 1 ) should not be significantly different from zero [19]. Table 4 summarizes the analytical results of the long-term stability test.…”

Section: Stability Assessment Of Crm 321 Long-term Stabilitymentioning

confidence: 99%

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Development of in-House Industrial Fluosilicic Acid Certified Reference Material: Certification of H2SiF6 Mass Fraction

et al. 2021

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Fluosilicic acid is a by-product of the chemical phosphate industry, mainly during the manufacture of phosphoric acid and triple super phosphate (TSP). To ensure the accurate measurement of the H2SiF6 mass fraction in this by-product, method validation is required, which needs a certified reference material (CRM) with its traceability to the International System of Units (SI). This work describes the development of a certified reference material of fluosilicic acid, which is commercially unavailable. Details of all steps, such as sample preparation, homogeneity and stability studies, value assignment, establishment of metrological traceability, and uncertainty estimation of the certified reference material, are fully described. The H2SiF6 mass fraction in the CRM was quantified by two analytical methods, i.e., UV-VIS as a primary method of analysis and flame mode atomic absorption spectroscopy (AAS) as a second method. It is worth noting that the results obtained from each method were in good agreement. The CRM certified value and corresponding expanded uncertainty, obtained from the combined standard uncertainty multiplied by the coverage factor (k = 2), for a confidence interval of 95%, was (91.5 ± 11.7) g·kg−1. The shelf life of the developed CRM is determined to be 1 year, provided that storage conditions are ensured. The developed CRM can be applied to validate analytical methods, improve the accuracy of measurement data as well as to establish the meteorological traceability of analytical results.

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Section: Stability Assessment Of Crm 321 Long-term Stabilitymentioning

confidence: 99%

Section: Stability Assessment Of Crm 321 Long-term Stabilitymentioning

confidence: 99%