Resumo Introdução O Ministério da Saúde (MS) é responsável pela vigilância da qualidade da água de consumo humano. A confiabilidade nos resultados do monitoramento de parâmetros analíticos minimiza riscos à saúde pública. Objetivo Retratar aspectos funcionais, a aplicação de ferramentas da qualidade e a aderência dos laboratórios públicos que atuam no monitoramento da água de consumo humano aos requisitos da norma ABNT NBR ISO/IEC 17025. Método A pesquisa foi realizada com 30 laboratórios públicos de todas as regiões do país, respondendo a um questionário elaborado com 49 perguntas sobre a formação e capacidade dos profissionais, garantia da validade dos resultados e sobre a determinação de parâmetros da qualidade da água. Resultados Dos 161 profissionais, 46% possuem mais de 10 anos de experiência e 65% têm formação superior. Capacitações específicas foram requeridas por todos. A validação dos métodos analíticos não foi realizada por 59%. Materiais de referência certificados são acessados por 41% e apenas 18% têm facilidade em adquiri-los. A participação em ensaios de proficiência foi reportada por 68% dos laboratórios, mas com poucos parâmetros avaliados e dificuldades em contratar provedores. Conclusão Evidenciou-se a necessidade de ações para fortalecimento da metrologia em laboratórios públicos que atuam na vigilância da qualidade da água.

Abstract Background The Ministry of Health (MS) is responsible for drinking water quality surveillance. Reliability in the results of monitoring analytical parameters minimizes public health risks. Objective To present functionals aspects and the application of quality tools by public laboratories that work to monitor the quality of drinking water. Method A survey was conducted with 30 public laboratories from all regions of the country, answering a questionnaire elaborated with 49 questions about the training and capacity of professionals, guaranteeing the validity of the results and about the determination of basic parameters of water quality. Results Of the 161 professionals, 46% have more than 10 years of experience and 65% have higher education. Specific training was required by everyone. The validation of the analytical methods was not performed by 59%. Reference materials are accessed by 41% and only 18% can acquire them easily. Participation in proficiency tests was reported by 68% of the laboratories, but with few parameters evaluated and difficulties in hiring providers. Conclusion The need for actions to strengthen metrology in public laboratories that work in water quality surveillance was highlighted.

Abstract The aim of this study was to obtain ionic quantification in periradicular medium after diffusion tests of the solution used inside root canals during the electrochemical dissolution of endodontic file fragments and the NiTi-containing dissolution product via an apical foramen. Thirty single-rooted extracted human teeth had root canals prepared and were attached to Eppendorf tubes filled with sterile saline. The samples were divided into 3 groups (n = 10) according to the solution used inside the root canal during the diffusion tests: Group 1: [NaF 12 g/L + NaCl 1 g/L]; Group 2: [NaF 12 g/L + NaCl 1 g/L + NiTi 0.50 g/L]; Group 3: [NaF 6 g/L + NaCl 0.5 g/L + NiTi 0.25 g/L]. The sample in each Eppendorf tube was then analyzed to assay the ionic quantification in periradicular medium. The groups were compared in relation to ionic quantifications (Kruskal-Wallis and Dunn’s tests, p ≤ 0.05). Group 2 showed significantly higher F-, Ni and Ti quantities than groups 1 and 3 (p < 0.05). Group 3 showed significantly higher Ti and Ni quantities than group 1, where no measurable quantities of Ti and Ni were observed (p < 0.05). The conclusions were that a 50% dilution of the NiTi-containing dissolution product resulted in significantly lower F-, Ni and Ti quantities compared to the undiluted product. The quantifications observed here suggest that irrigation is recommendable during the electrochemical dissolution process to reduce the resultant ion concentrations in both the root canal and the periradicular medium.

Abstract: The production of selenium and selenomethionine certified reference material in yeast (Saccharomyces cerevisiae) and certification studies for its homogeneity, stability and characterization, have been accomplished before in our laboratory. Based on such results and experience of our laboratory in Metrology and according to literature, we discuss here the advantages and limitations of the calibration by “single point” as an alternative method to the classical calibration curve. The method traceability to the SI is checked in order to secure a robust determination. As the model analyte the mass fraction of the Se species selenomethionine is measured and compared in yeast samples. Results showed that a good agreement was obtained by both methods (the reference one of the calibration curve and “single point calibration”). This simple approach can be used for routine control of selenomethionine in commercial supplements of yeast samples, but the work carried out demonstrated its potential for the general routine quantitative analysis of the possible and important selenium species in other Se-enriched supplements commercialised in Latin America (i.e. mushrooms, garlic etc).

Resumen: La producción de material de referencia certificado de selenio y selenometionina en levadura (Saccharomyces cerevisiae) y los correspondientes estudios de certificación de homogeneidad, estabilidad y caracterización, se han llevado a cabo con anterioridad en nuestro laboratorio. Basándonos en los resultados y la experiencia de nuestro laboratorio en Metrología y según la bibliografía, discutimos aquí las ventajas y limitaciones de la calibración de “un punto” como un método alternativo a la curva de calibración clásica. Se verificó la trazabilidad del método al SI para asegurar una determinación robusta. Como analito modelo, se determina la especie de selenio, seleniometionina, presente en muestras de levadura. Los resultados obtenidos por ambos métodos (curva de calibración y la calibración de “un punto”) muestran una buena concordancia. Esta aproximación simple demostró su utilidad para el control rutinario de selenometionina en suplementos comerciales de levadura y su potencial para el análisis cuantitativo rutinario general de las otras importantes especies de selenio de interés en otros suplementos enriquecidos en Se comercializados en Latinoamérica (es decir, champiñones, ajo, etc.)