Abstract:
Particle size analysis by dynamic light scattering is a technique applied in the characterization of nanodispersions, microemulsions and colloidal solutions. The test results should be presented with the estimated measurement uncertainty. The lack of such information may be relevant to the validity or the application of the test results or even may affect the conclusion on conformity with a specified limit. The aim of this paper is to present the estimation and the evaluation of the measurement uncertainty of particle size – light scattering (DLS) assays. The method for estimating was based on a guide to measurement uncertainty expression which employs the “Uncertainty Propagation Law” and identified 14 sources of uncertainty. The result of the expanded uncertainty is 4.0 % with 95 % coverage probability for a material of 101.8 nm in diameter, meeting the expectations of the laboratory, based on information found in the literature. The repeatability obtained was 1.0 %, within the range of values stipulated in the reference standard (less than 2 %). From the evaluation of the contribution of each source of uncertainty the ones that will have the greatest impact if actions were implemented to reduce them were selected.
Reference:
MATTEUCCI, Cyntia; DINISB, Aline Cotta; GUIMARÃES, Kleber Lanigra. Cálculo e avaliação da incerteza estimada de medição dos ensaios de análise de tamanho de partículas por espalhamento dinâmico de luz (DLC). Revista IPT Tecnologia e Inovação, v.1, n.5, p. 67-84, ago., 2017.
Access to the article in the newspaper site:
http://revista.ipt.br/index.php/revistaIPT/article/view/45/50
Particle size analysis by dynamic light scattering is a technique applied in the characterization of nanodispersions, microemulsions and colloidal solutions. The test results should be presented with the estimated measurement uncertainty. The lack of such information may be relevant to the validity or the application of the test results or even may affect the conclusion on conformity with a specified limit. The aim of this paper is to present the estimation and the evaluation of the measurement uncertainty of particle size – light scattering (DLS) assays. The method for estimating was based on a guide to measurement uncertainty expression which employs the “Uncertainty Propagation Law” and identified 14 sources of uncertainty. The result of the expanded uncertainty is 4.0 % with 95 % coverage probability for a material of 101.8 nm in diameter, meeting the expectations of the laboratory, based on information found in the literature. The repeatability obtained was 1.0 %, within the range of values stipulated in the reference standard (less than 2 %). From the evaluation of the contribution of each source of uncertainty the ones that will have the greatest impact if actions were implemented to reduce them were selected.
Reference:
MATTEUCCI, Cyntia; DINISB, Aline Cotta; GUIMARÃES, Kleber Lanigra. Cálculo e avaliação da incerteza estimada de medição dos ensaios de análise de tamanho de partículas por espalhamento dinâmico de luz (DLC). Revista IPT Tecnologia e Inovação, v.1, n.5, p. 67-84, ago., 2017.
Access to the article in the newspaper site:
http://revista.ipt.br/index.php/revistaIPT/article/view/45/50
