In the present study a spectrophotometric method for Cr(VI) determination in organic fertilizers, especially those from tanning industry residues, is proposed. Conditions for chromium extraction, extract clean-up and analytical characteristics of the method were established. The method is based on the complexation of Cr(VI) with 1,5-diphenylcarbazide (DPC) in acid medium (pH 2.0). A mixture of NaOH and Na2CO3 solution at 0.125 and 0.07 mol L–1 (pH 12), respectively, and heating at 90 °C for 60 min were the best conditions for chromium extraction. Florisil and activated charcoal were tested for clean-up of the extract, with activated charcoal being effective. Under the established conditions, the calibration linear range is up to 2500 μg L–1 Cr(VI), the results obtained are in agreement with the value of a certified reference material (CRM041), precision is better than 5% for five consecutive determinations of a solution at 1000 μg L–1 of Cr(VI) and the limit of quantification is 1.62 μg g–1. In can be concluded that the method is robust, accurate and precise, and can be easily applied for the determination of Cr(VI) in routine analysis, since it complies with legislation of most countries regarding the maximum allowed concentration of 2 μg g–1 of Cr(VI). CrVI Cr VI Cr(VI fertilizers residues proposed extraction cleanup clean 1,5diphenylcarbazide 15diphenylcarbazide diphenylcarbazide 1,5 1 5 DPC (DPC pH 2.0. 20 2.0 . 0 2.0) NaCO Na CO Na2CO 0125 125 0.12 007 07 0.0 L1 L L– 12, 12 , 12) respectively 9 C 6 effective 250 CrVI, CRM041, CRM041 CRM (CRM041) 100 162 62 1.6 g1 g robust precise analysis g– CrVI. 5diphenylcarbazide 15 1, 2. 012 0.1 00 0. 25 CRM04 (CRM041 10 16 1. 01 CRM0 (CRM04 (CRM0 (CRM

The full process of fresh egg preservation presents limitations and is associated with high transportation costs, while processed powdered eggs offer numerous advantages, such as high stability against degradation, providing extended shelf life, easy production, transportation, and favorable storage conditions. Traditional methods for determining the proximate composition of eggs and derivatives lack the capability to eliminate the matrix effect and do not guarantee adequate precision of the results. Therefore, Certified Reference Material (CRM) are the most suitable and effective tool to achieve this purpose. However, in Brazil, CRMs for powdered egg matrix are currently unavailable, although it is not possible to eliminate matrix effects, these can be included in the measurement uncertainty of each CRM. This study aimed to develop a candidate CRM for the powdered egg matrix with the requirements for the competence of testing and calibration laboratories (17034:2016) for proximate composition analyses. The analysis of variance (ANOVA) results for stability and homogeneity indicated no significant variation among the data obtained in the tests and the storage time of the material. Consequently, it was concluded that the powdered egg matrix is stable under simulated transportation conditions (short-term stability) as well as storage conditions (long-term stability) and exhibits adequate homogeneity for a CRM candidate. costs advantages degradation life production Therefore (CRM purpose However Brazil unavailable effects 170342016 17034 2016 (17034:2016 analyses ANOVA (ANOVA material Consequently shortterm short term longterm long 17034201 1703 201 (17034:201 1703420 170 20 (17034:20 170342 17 2 (17034:2 1 (17034: (17034 (1703 (170 (17 (1 (

In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted with n-propanol and water (1.4 mol L-1 HNO3) to form a microemulsion (ME) before its introduction in the HR-CS FAAS using a flow injection mode. The sample B-01 (obtained from soybean oil) was used for optimisation of the instrumental parameters. The accuracy of the proposed method was checked by analysis of certified reference material (CRM) Conostan BDM2A (for K and Na) and BDM2B (for Ca and Mg) and by comparison with acid digestion and recovery tests (for Zn, Fe, Cu, Cr and Al). The obtained results for CRM analysis showed good agreement with certified values within 95% of confidence (Student’s t-test). Recovery tests values ranged from 87-114%. The method developed for the analysis of biodiesel samples is accurate, simple, fast, and suitable for routine application.

A newly analytical method has been developed to determine total chromium and speciation of this element in water samples through dispersive liquid-liquid microextraction combined with a high-resolution continuum source flame atomic absorption spectrometry. The most significant variables affecting complexation and extraction were optimized by using response surface methodology and univariate optimization. The best conditions for both the complexation and extraction elements in this study were: complexing agent ammonium pyrrolidine dithiocarbamate (APDC 6.0 mmol L-1); pH at 2.0 (CrVI) and at 7.0 (Cr total); NaCl (5% m/v); 1-undecanol (50 µL) and ethanol 300 (CrIV) and 275 µL (total Cr). Under optimal conditions, this method resulted in a 20-100 µg L-1 linear range for CrVI and total chromium, detection limits of 0.35 (CrVI) and 6.7 µg L-1 (total Cr), as well as enriching factor of 26 (CrVI) and 19 for total Cr. The method accuracy was carried out by using certified water reference material (NIST CRM 1643e), and the results achieved were in agreement with the certified value (t-test at a confidence interval of 95%). The method developed was applied in samples of mineral water, tap water (the recovery values ranged from 88 to 115%) and seawater.

RESUMO Introdução: Rastreabilidade metrológica é um tema da metrologia pouco conhecido e discutido nos laboratórios clínicos, apesar de ser a base para resultados comparáveis; associa-se a material de referência certificado (MRC) e a método de referência (MetR). Quando usada na cadeia de suprimentos pelos fabricantes de conjuntos diagnósticos, atua na garantia da exatidão dos resultados produzidos pelos laboratórios. Objetivo: Apresentar a disponibilidade das informações sobre rastreabilidade metrológica fornecidas pelos fabricantes de conjuntos diagnósticos. Método: O estudo foi feito com as informações obtidas nos conjuntos diagnóstico de glicose (GLI), ureia (URE), creatinina (CRE), ácido úrico (AU) e colesterol (COL) participantes de um programa de ensaio de proficiência ao longo de 2012 e 2013. Resultados e conclusão: Na pesquisa sobre produtores de materiais de referência (MRs) e de produtos disponibilizados, foram encontrados 18 produtores e 204 analitos para a área de laboratórios clínicos. No estudo sobre rastreabilidade metrológica, foi demonstrado o uso preferencial de MRC pelos fabricantes de conjuntos diagnósticos (GLI 60%; URE 69%; CRE 60%, AU 50% e COL 43%), bem como o dado importante de que há um número expressivo de conjuntos diagnósticos que não informa rastreabilidade (GLI 16%; URE 19%; CRE 16%, AU 13% e COL 5%), embora ela seja requisito em norma nacional que regulamenta o registro de produtos. Esperamos que este estudo contribua para sensibilizar a comunidade laboratorial da necessidade de conhecimento mais abrangente acerca deste assunto e que estimule as instituições relacionadas com a disseminação de conhecimento na área de laboratório clínico a promover discussões sobre o tema.

ABSTRACT Introduction: Metrological traceability is a little-known and little-discussed metrology theme in clinical laboratories, although it is the basis for comparable results. It is associated with certified reference material (CRM) and reference method (RMet). When it is used in the supply chain by diagnostic kit manufacturers, it ensures accuracy of the results yielded by laboratories. Objective: This study shows the availability of information on metrological traceability provided by diagnostic kit manufacturers. Method: It was done with the information obtained in kits of glucose, urea, creatinine, uric acid and cholesterol participants in a proficiency testing program throughout 2012 and 2013. Results and conclusion: In the research, 18 producers of reference materials (RMs) and 204 measurands available for laboratory medicine were found. In the study of metrological traceability, the preferential use of CRM was demonstrated by kit manufacturers (glucose 60%, urea 69%, creatinine 60%, uric acid 50%, and cholesterol 43%). An important factor is that there are a significant number of kits that do not report traceability (glucose 16%, urea 19%, creatinine 16%, uric acid 13%, and cholesterol 5%), although it is a requirement for product registration in Brazil. We hope that this study will contribute to sensitize the laboratory community to the need for a more comprehensive knowledge of this subject, and that it will stimulate institutions involved in the dissemination of knowledge in laboratory medicine to hold discussions on this topic.

Cloud point extraction was employed for the separation and preconcentration of cadmium and lead prior to the determination by thermospray flame atomic absorption spectrometry. Di-2- pyridyl ketone salicyloylhydrazone (DPKSH) was used as complexing agent and the cadmium and lead complexes were extracted from the aqueous phase by the Triton X-114 surfactant. The variables associated with the preconcentration (pH as well as DPKSH, surfactant and electrolyte concentration) were optimized by using a full factorial design with two levels, four variables and a central composite. Under the optimized conditions, a sample volume of 100 µL was introduced into a hot Ti tube at a flow rate of 0.6 mL min-1 and the integrated absorbance was measured. Calibration curves were obtained with linear ranges of 0.075-2.0 µg L−1 (Cd) and 2.5-100 µg L−1 (Pb). The detection limits of 0.04 µg L−1 (Cd) and 1.3 µg L−1 (Pb) (99.7% confidence level) were obtained. The proposed method was applied to hemodialysis solutions and water samples. The accuracy of the method was evaluated by analyzing a certified reference material (NIST CRM 1643e) and the results were in agreement with the certified values at a 95% confidence level according to t-test.

Material de referência certificado (CRM) desempenha um papel vital para a garantia de controle em análises ambientais, uma vez que a qualidade dos dados resultantes de medições ambientais tem importância crucial. Este artigo apresenta os resultados de estudos realizados para a certificação dos compostos planejados como candidato a material de referência, que são dezesseis hidrocarbonetos policíclicos aromáticos (PAHs) dissolvidos em tolueno (naftaleno, acenaftileno, acenafteno, fluoreno, antraceno, fenantreno, fluoranteno, criseno, benzo[a]antraceno, pireno, benzo[k]fluoranteno, benzo[b]fluoranteno, benzo[a]pireno, dibenzo[a, h]anthaceno, indeno[1, 2, 3-cd]pireno e benzo[ghi]perileno). Este é o primeiro CRM brasileiro de PAH desenvolvido pelo Inmetro. O processo de certificação inclui a validação do método GC/IDMS (espectrometria de massa de diluição isotópica acoplada a cromatografia gasosa), o estudo de homogeneidade, a estabilidade em condição de transporte e de armazenamento, além de cálculo de incertezas de medição.

Certified reference material (CRM) plays a vital role for quality control assurance in environmental analysis, because the quality of data arising from measurements has crucial importance. This article presents the results from studies carried out for certification of a candidate reference material composed by sixteen polycyclic aromatic hydrocarbons (PAHs) dissolved in toluene (naphthalene, acenaphthylene, acenaphtene, fluorene, anthracene, phenanthrene, fluoranthene, chrysene, benzo[a]anthracene, pyrene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthacene, indeno[123-cd]pyrene and benzo[ghi]perylene). This is the first Brazilian PAH CRM developed by Inmetro. The certification procedure includes validation of the GC/IDMS method (isotopic dilution mass spectrometry coupled to gas chromatography), homogeneity study, stability studies under transport and storage conditions and estimation of measurement uncertainties.

The use and characterization of the first Certified Reference Material (CRM) of Brazilian coal for analytical quality control are presented. All results were determined within the limits of repeatability and reproducibility allowed under the standards. Notable among the characterization parameters was the mineral matter content (45.39%) obtained by an alternative procedure showing a low relative error (-2.1%) compared to the standard technique (low ashing temperature). The possible expanded application of this CRM application in national laboratories, beyond the certificated and reference parameters, has advantages such as lower cost and easy availability, but round robin tests must be performed.

Este artigo apresenta os resultados dos estudos realizados com o candidato a material de referência certificado (MRC) de metronidazol, primeiro MRC deste fármaco disponibilizado no mercado e segundo MRC de fármacos brasileiro. Os estudos incluem a determinação dos teores de impurezas orgânicas, inorgânicas e voláteis, validação do método analítico de cromatografia líquida de alta eficiência (CLAE), estudos de estabilidade em condições de transporte e estocagem, estudo de homogeneidade, determinação do teor de metronidazol por balanço de massa, confirmação deste valor por calorimetria exploratória diferencial (DSC) e cálculo de incertezas de medição.

This paper presents the results of the studies carried out with the candidate certified reference material (CRM) of metronidazole, first CRM of this active pharmaceutical ingredient (API) available on the market and second Brazilian CRM of an API. The investigation includes the determination of organic impurities, inorganic impurities and volatiles, validation of the HPLC-DAD method, stability studies under transport and storage conditions, homogeneity testing, calculation of metronidazole content by mass balance, confirmation of the certified value by differential scanning calorimetry (DSC), and estimation of measurement uncertainties.

Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This paper presents the results of these studies. The characterization, homogeneity, short-term stability and long-term stability uncertainty contributions values were 0.00500, 0.0166, 0.0355 and 0.0391 mg g-1, respectively. The certificated value for water content of bioethanol fuel was (3.65 ± 0.11) mg g-1. This CRM is the first and up to now the unique in the world.

A coulometria é considerada o método de maior qualidade metrológica para medição de quantidade de substância de padrões primários. Entretanto, a contaminação de sais de elevada pureza está presente em níveis traços sendo necessária a sua identificação e quantificação. Este trabalho apresenta os estudos desenvolvidos pelo Inmetro (Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, Brasil) para determinar a pureza do cloreto de potássio (KCl) por titulação coulométrica a corrente constante, além da determinação do brometo como seu principal contaminante por cromatografia iônica (IC). Esses estudos foram necessários para desenvolver material de referência certificado (MRC) de KCl para garantir a qualidade dos resultados das medições químicas principalmente as de titulometria. A caracterização do candidato a MRC de KCl apresentou pureza de 99,9662%, a qual foi obtida após a correção do brometo, em fração mássica, obtido por IC, de 182,47 ± 3,03 mg kg-1 (incerteza expandida, k = 2, para um nível de confiança de aproximadamente de 95%).

Coulometry is considered the highest metrological method for measuring the amount of substance of high-purity compounds. However, the contamination of the high purity salts is present in trace levels and its identification and quantification are necessary. This work aims to present the studies performed by Inmetro (National Institute of Metrology, Standardization and Industrial Quality, Brazil) to determine the purity of potassium chloride (KCl) by constant-current coulometric titration, as well as the determination of bromide as the main impurity in the KCl through ion chromatography (IC). These studies were needed to develop certified reference material (CRM) of KCl to guarantee the quality of the chemical measurements, mainly those performed by titrimetric analysis. The characterization of the candidate CRM of KCl by coulometric titration presented the purity of 99.9662%. This value was obtained after bromide correction of 182.47 ± 3.03 mg kg-1 (expanded uncertainty for k = 2, for a confidence level of approximately 95%) for the mass fraction bromide assayed by IC.

Este artigo descreve os estudos realizados com o candidato a Material de Referência Certificado (MRC) de captopril, primeiro MRC de fármacos no Brasil, incluindo a determinação de impurezas (orgânicas, inorgânicas e voláteis), testes de homogeneidade, testes de estabilidade de curta e longa duração, cálculo do teor de captopril por balanço de massa e estimativa da incerteza de medição associada ao valor certificado.

This paper describes the studies performed with the candidate Certified Reference Material (CRM) of captopril, the first CRM of an active pharmaceutical ingredient (API) in Brazil, including determination of impurities (organic, inorganic and volatiles), homogeneity testing, short- and long-term stability studies, calculation of captopril content using the mass balance approach, and estimation of the associated measurement uncertainty.

O presente trabalho descreve o desenvolvimento de um material de referência certificado (MRC) referente a soluções de etanol em água em cinco concentrações diferentes, abordando todas as etapas necessárias para o desenvolvimento de um MRC, conforme prescreve as ISO GUIDE 30, 31, 32, 33, 34 e 35. O desenvolvimento deste MRC originou-se nas determinações da Portaria Inmetro n° 006 de 2002, que assegura que todos os etilômetros a serem utilizados no Brasil deverão ter os seus modelos aprovados, e as verificações realizadas a partir de ensaios com soluções de etanol em água. Após um treinamento, em fevereiro de 2003, no The Federal Institute for Material Research and Testing - BAM, que é um instituto metrológico alemão designado, a Dquim iniciou o processo de desenvolvimento deste MRC, o qual foi concluído em agosto de 2004. No Inmetro desenvolveu-se inicialmente o procedimento de preparo individual, onde as soluções do MRC são preparadas em garrafas de 0,5 L. Atualmente está se estudando, no Inmetro, o desenvolvimento do procedimento em batelada, o que corresponde ao preparo das soluções do MRC em garrafas de 5,0 L, com seqüente distribuição em garrafas de 0,5 L. Pode-se considerar que o processo de desenvolvimento deste material de referência certificado está num período contínuo, onde melhorias estão sendo viabilizadas, como a utilização da técnica de DSC para a determinação da pureza do etanol, e a finalização do desenvolvimento do procedimento em batelada, que será um importante passo para a agilização no processo de preparo destas soluções. Desta forma, o desenvolvimento deste MRC contribui de forma significativa, para confiabilidade nas medições realizadas com etilômetros, tendo incerteza de medição declarada. Outro ponto importante é que a partir deste desenvolvimento, possibilita-se a sociedade um MRC que pode ter aplicações variadas, não se restringindo somente a ensaios com etilômetros.

The present work describes the development of a certified reference material (CRM) composed of solutions of ethanol in water in five different concentrations, and all stages necessary for the development of an CRM, according to the guidelines of ISO GUIDES 30, 31, 32, 33, 34 and 35. The development of this CRM has been determined by Inmetro Rule n. 006 of 2002, which requires that all breath alcohol analyzers being used in Brazil shall have their respective models approved and that the subsequent verifications shall be performed based on tests with solutions of ethanol in water. As a result, the development of this CRM significantly contributes to the reliability of measurements performed with breath alcohol analyzers, with stated measurement uncertainty. Equally important, this development provides society with a CRM that may have multiple applications, not restricted to the verification of breath alcohol analyzers.