ISBN: 978-65-994975-8-2
Autores: Mariana Cardoso de Oliveira, Vanderléa de Souza, Marcelo Dominguez de Almeida
Palavras-chave: nitrate, nitrite, meat product, validation of method
Resumo: Nitrate and nitrite measurement is a fundamental part of quality control in the meat products industries. Ensuring the technical validity of the results of these measurements can be achieved through the adoption of appropriate metrological tools such as method validation. In this study, the measurement of the mass fractions of nitrite and nitrate ions was performed by ion chromatography with UV detection. The method was linear (r > 0.99) over the working range. Limits of quantification values for measuring nitrite and nitrate in meat product were 10 mg kg-1 and 100 mg kg-1 , respectively. The mean values of recovery at all evaluated mass fraction levels were within the range of 88 % to 106 %. All the validation parameters resulted as satisfactory and the method was considered adequate for the intended use.
Autores: Alex Krummenauer, Hugo Marcelo Veit, Marcelo Pilotto Cenci, Luis Henrique Lapazin
Palavras-chave: linearity, limit of detection (LOD), limit of quantification (LOQ), working range, energy dispersive X-ray fluorescence (EDXRF)
Resumo: Using a portable energy dispersive X-ray fluorescence (EDXRF) spectrometer and certified reference materials, the linearity, the limit of detection (LOD), the limit of quantification (LOQ), and the working range of the method were determined for the quantitative analysis of base and precious metals in liquid matrices. As the EDXRF method is not standardized and strongly sensitive to matrix effects, these calculations are essential to its analytical validation. In this study, the resulting R2 values were higher than 0.99 and the residuals had random distribution. The LOD and LOQ values were considered low, close to the resolution of the spectrometer. Thus, our calculations confirmed the analytical validation of the portable EDXRF method in liquid matrices. The utilization of portable EDXRF equipment in the quantitative measurement of elements in liquid matrices is innovative and reveals new fields of application for this type of instrument.
Autores: Natalia Cambiaghi Atilio, Elcio Cruz de Oliveira, Fernando Luis Fertonani
Palavras-chave: Hydrous ethanol fuel, ethanol pH, combined glass electrode, pH indicator
Resumo: The pH is one of the quality parameters of hydrous ethanol fuel (HEF), being established by Brazilian standard ABNT NBR 10891 and by American standard ASTM D 6423. The present work aims to compare the measurement systems proposed by the standards for measuring pH in hydrous ethanol fuel and compare them with the pH range found from pH indicators, considered as a standard measurement. The results reveal that the pH values obtained by the different systems used are statistically different from each other and different from the range found by the indicators.
Autores: Mariana Cardoso de Oliveira, Vanderléa de Souza, Marcelo Dominguez de Almeida
Palavras-chave: nitrate, meat product, reference material, feasibility study.
Resumo: Nitrate measurement is a fundamental part of quality control in the meat products industries. Ensuring the technical validity of the results of these measurements can be achieved through the adoption of appropriate metrological tools such as reference materials. The technical feasibility for producing a nitrate reference material in a meat product was evaluated by preparing a batch of material on a small scale. The adequacy of the preparation procedure was evaluated by means of pertinent physicochemical and microbiological measurements. A batch of 175 units containing approximately 5 g of freeze-dried ham in each package was produced. The batch was submitted to preliminary studies to assess homogeneity and stability under transport conditions, in accordance with ISO 17034 and the applicable ISO guides.
Autores: Marina Zuffo, DAIANE CHIARELLO, JULYANA PITTOL MARTINS, JOSEANE CRISTINA BASSANI, MAICON RODRIGO Zangalli
Palavras-chave: peixe, ensaios de proficiência, qualidade.
Resumo: Para que o crescimento e desenvolvimento da cadeia pesqueira aconteça de maneira sustentável, é necessário o desenvolvimento de bases científicas e tecnológicas sólidas, que auxiliem na garantia da qualidade desta matéria prima. Uma das principais maneiras de comprovar a qualidade destes produtos é fornecida por meio de resultados analíticos. Neste contexto, o desenvolvimento de materiais de referência destinados a ensaios de proficiência em matriz de pescado contribui para o avanço científico, tecnológico e de qualidade desta matéria prima. Este trabalho descreve as etapas de produção de um material de referência destinado a ensaios de proficiência em matriz pescado. O estudo abrange as etapas de seleção do material, preparação e desenvolvimento dos estudos de homogeneidade e estabilidade a curto prazo simulando condições de transporte. A avaliação dos resultados foi apresentada por meio de desvio padrão de Horwitz e desvio padrão pela experiência de rodadas anteriores de programas de ensaio de proficiência, realizando-se comparações entre ambos. Verificou-se que o lote de material produzido se apresentou homogêneo e se manteve estável durante o estudo de estabilidade, possibilitando sua utilização em ensaios de proficiência.
Autores: Daniella Paiva Bonfim, Bruno Cosme, Jailton Carreteiro Damasceno, José Mauro Granjeiro, Fernanda Leve
Palavras-chave: Validation, Cell count, Neubauer chamber, Automatic count.
Resumo: The quantification of biological processes has gained importance in metrology, as its application in diagnosis and personalized therapy has been increasing the demand of the biotechnology sector. Considering that the cell is the microscopic and functional unit of living beings, cell count is critical for the reproducibility of the in vitro study. This work aims to determine the measurement uncertainty and the commutability of the methods of manual cell counting in a Neubauer chamber and automatic cell counting, both image-based and widely used. For this, we used different amounts (1×105 -6×105 ) of HCT-116 cells, a well-established line whose authenticity was confirmed by STR analysis. Initially, we checked if 20 up/down movements, performed with the micropipette, are enough to maintain the homogeneous distribution of cells in the four most outer quadrants of the Neubauer chamber. Then, different amounts of cells (1×105 -6×105 ) were prepared using a balance or calibrated micropipettes, stained with trypan blue (1:1) and counted in an automatic counter or a Neubauer chamber, in quadruplicate. Data analysis was performed using the GraphPad Prism 6 program, and the significance analysis was performed using the one-way ANOVA test, Bonferroni post-test, and simple linear regression. The measurement uncertainty was estimated using the calculations recommended in the ISO GUM. The results show that the homogenization provided an equitable distribution (p>0.05) of cells in the four most outer quadrants of the Neubauer chamber, regardless of the cell concentration used. Manual and automatic counting showed the same linear correlation between the expected cell number and the observed cell number, showing the compatibility of the methods. As a function of the cell concentration analyzed, the measurement uncertainty ranged between 6-18% for automatic counting and between 11-24% for manual counting. However, we observed that the commutativity of the manual and automatic counting methods depends on the dilution preparation method and that only the gravimetric dilution presented commutativity (p>0.05). The results show that performing 20 up/down movements are sufficient to homogenize the samples for counting in quadruplicate in the Neubauer chamber and the automatic counter, that counting in 4 and 9 quadrants are equivalent, that the manual and automatic methods are switchable when the dilutions are prepared by gravimetry and have similar measurement uncertainty, in the range between 6 and 24%. We intend to use these results to validate manual counting methodology and automatic counting of human cells, allowing a possible comparison with other automated methodologies, including flow cytometry and realtime electrical impedance analysis.
Autores: Giulia Gall delgado de souza, Bruno Cosme, José Mauro Granjeiro, Fernanda Leve
Palavras-chave: Validation; ddPCR; cancer
Autores – Bárbara Gomes de Carvalho, Wanderson de Souza, Lorena Gonçalves Henriques Corrêa Maduro, Camila Brand de Carvalho, Celso Barbosa de Sant’Anna Filho, José Mauro Granjeiro, Leonardo da Cunha Boldrini Pereira, Priscila Grion
Palavras-chave: Nanotoxicidade, Nanopartícula de prata, Hep-G2, Viabilidade celular.
Resumo: O crescimento exponencial da nanotecnologia na pesquisa e no mercado é algo notável, sendo as nanopartículas de prata (AgNPs) uma das mais exploradas. Já é conhecido que AgNPs possuem efeitos citopatotóxicos frente às células de fígado humano (HEP-G2). Baseado nisso, esse estudo buscou avaliar a alteração da viabilidade celular (HEP-G2) frente à exposição de diferentes concentrações de AgNPs (0,001 – 10 µg/mL) no período de 48h de exposição utilizando testes de viabilidade (MTT e LDH). Inicialmente, as AgNPs foram caracterizadas pelos métodos de espalhamento de luz dinâmico (DLS) e microscopia eletrônica de transmissão (MET). Os resultados demonstraram que as nanopartículas utilizadas apresentam morfologia esférica com diâmetro médio de 20±10 nm. Após a interação celular foi possível observar por MTT redução de viabilidade nas concentrações de 1; 2,5; 5; 7,5 e 10 µg/mL, alcançando uma redução próxima dos 50% de viabilidade com IC50>10 µg/mL. O ensaio de LDH destacou que não há alteração na liberação de lactato desidrogenase para o meio extracelular. Esses resultados revelam que mesmo nas menores doses houve alteração considerada significativa da viabilidade e, que possivelmente, as células não sofrem lise de membrana. Esses dados compilados irão contribuir para informações nanotóxicológicas e, consequentemente, de forma indireta para o processo de padronização das técnicas utilizadas.
Autores: Mayane Ribeiro de Faria Henrique, Aurea Valadares Folgueras Flatchart, Vanderlea de Souza, Jose Mauro Granjeiro, Roberto Becht Flatschart, Flavio Guimarães da Fonseca, José Lafaiete Palles Ramos Júnior, Shana Priscila Coutinho Barroso, Marcos Bryan Heinemann
Palavras-chave: Validação de método, RNA, ddPCR, BVDV, flavivirus
Resumo: A increasingly common way for the diagnostics of viral agents is to carry out PCR from biological samples, which can detect their nucleic acid during the acute phase of the disease. Taking into account the need for quality control of PCR tests in laboratories accredited by ISO/IEC 17025:2017, we intend to carry out feasibility studies for the production of Reference Materials (MR) for these molecular tests, using BVDV in the matrix serum as a model. The first step for this goal was the validation of an analytical method for quantification of viral RNA to characterize the material under study. Primers and probe from a commercial qualitative assay kit designed for Real Time RT-PCR (VetMax Gold BVDV – Thermo Fisher) were used for quantification of BVDV by ddPCR. The technique was optimized and a Detection Limit of 13 copies/µL was determined, allowing a Quantification Limit of 38 copies/µL. The method showed to be linear over two orders of magnitude and will be used in the homogeneity study and long-term stability tests for the pilot batch of BVDV in Fetal Bovine Serum MR, as a prototype for the production of MR intended for PCR of BVDV and other Flaviviridae.
Autores: Lorena de Oliveira Neves, Bruno Carius Garrido, Jose Mauro Granjeiro, Luciene Bottentuit López Balottin
Palavras-chave: volumetria, incerteza de medição, ensaios biológicos, in vitro, micropipetas
Resumo: A incerteza na determinação volumétrica de instrumentos como as pipetas, entre outros, é um dos dados mais relevantes para a garantia da qualidade de ensaios biológicos com células, podendo ser impactada por parâmetros sistemáticos e aleatórios. Foram comparadas estratégias de remoção de soluções das placas de cultura de células comumente utilizadas, incluindo ou não o uso de micropipetas, para avaliar a repetibilidade de tais métodos e quantificar a incerteza de medição associada. Removendo soluções por inversão, não vemos diferença significativa nos volumes obtidos entre as rodadas, dentro das mesmas condições. As micropipetas multicanal apresentaram valores de incerteza expandida diferentes entre os canais. A escolha da estratégia de enxágue de soluções em seus protocolos, portanto, impacta no aumento da incerteza associada ao cálculo do resultado de medição em ensaios biológicos com células.
Autores: Marina Zuffo, Maicon Rodrigo Zangalli, Joseane Cristina Bassani
Autores: Priscila G.M. Borchio, Wanderson de Souza, Leonardo Boldrini, Ana R. Ribeiro, José Mauro Granjeiro
Autores: José Lafaiete Palles Ramos Junior, Oscar de Souza Monteiro, Nathalia Correia dos Santos, Raquel Correia, Danielle P Cavalcanti, Juliana L Martins, Leonardo da Cunha Boldrini Pereira, José Mauro Granjeiro, Aurea Valadares Folgueras-Flatschart
Autores: Priscila Laviola Sanches, Luths R O Geaquinto, Marcio Lorencini, Desiree C Schuck, Bruna B S Sievers, Meg C C Costa, Carolina M Catarino, Ana R L Ribeiro, Jose M Granjeiro
Autores: Beatriz Kopke de Assis Dal-Cheri, Wanderson de Souza, Celso Barbosa de Sant’Anna Filho, Luís Mauricio Trambaioli da Rocha e Lima, José Mauro Granjeiro, Paulo Emílio Corrêa Leite, Leonardo da Cunha Boldrini Pereira