Production Of Reference Materials Research Articles

The relevance of linguistic and professional knowledge as contributing factors for technical translation in the area of aircraft (maintenance).

For security reasons, quantity and constant updates, it is impracticable to translate documents related to the operation and maintenance of aircraft. However, most professionals in this field are not native English speakers and are in contact with this English written documentation on a daily basis so they can do their job. Therefore, it is important that aviation professionals have materials of reference, especially for technical terms, that are reliable sources of information. However, in addition to the lack of this type of material, there is a challenge for its development. The objective of this article is, based on theoretical references and examples from the practice of researching and teaching English for specific purposes, to encourage the discussion about the teamwork of the language teacher and the professional of aircraft maintenance in the production of reference materials, such as technical glossaries. Based on the arguments presented, it is concluded that this partnership has benefits for both areas, languages and technical.

A comparison of different calibration strategies for the trace analysis of soil samples by inductively coupled plasma mass spectrometry (ICP-MS)

The National Metrology Institute of South Africa (NMISA) is expanding its capabilities in the field of the analysis of trace and ultra-trace levels of toxic and minor elements in environmental samples, with a special focus on soils to support projects of the University of Pretoria (UP) in the field of veterinary geology for the One Health Platform. The most accurate calibration strategy developed by the laboratory involves double isotope dilution analysis, where a stable isotope standard of the element of interest is used as the ideal internal standard. External calibration is the most commonly used calibration strategy for elemental analysis. To reduce the impact of instrumental drift on the accuracy of the measurement results, nominally the same amount of an internal standard is added to the samples and the standards. Standard addition is a calibration strategy that could eliminate the issue of matrix effects for trace and ultra-trace elemental analysis, because the calibration standards are added as spikes to aliquots of the sample to prepare the calibration curve. The purpose of the study was to compare the results obtained for the analysis of trace elements in soil samples using the calibration strategies of isotope dilution analysis; gravimetric external calibration with gravimetric internal standardisation; as well as gravimetric standard addition with gravimetric internal standardisation. The aim was to show that the application of gravimetric preparation to the more routine calibration approaches of external calibration and standard addition could achieve very comparable results and associated measurement uncertainties to isotope dilution analysis. The application of gravimetric sample preparation could assist routine laboratories, that have significant resource constraints, to improve the accuracy of their measurement results. These approaches could also be used in the experimental homogeneity and stability studies required for the production of reference materials, where high precision methods are required.

Preparation and characterisation of IAEA-603, a new primary reference material aimed at the VPDB scale realisation for δ13 C and δ18 O determination.

NBS19 carbonate, a primary reference material (RM) for the Vienna Pee Dee Belemnite (VPDB) scale realisation introduced in 1987, was exhausted in 2009, and no primary RM was available for several years. This study describes the preparation and characterisation of a new RM, IAEA-603 (Ca-carbonate, calcite of marble origin), which shall serve as a new primary RM (replacement for NBS19) or primary calibrator aimed at the highest realisation of the VPDB scale for δ13 C and δ18 O values, including the VPDB-CO2 δ18 O scale. IAEA-603 preparation and characterisation (value transfer) against NBS19 were performed by addressing the major modern technical requirements for the production and characterisation of RMs (ISO Guide 35). IAEA-603 was produced in a large quantity, and the first batch was sealed into ampoules (0.5 g) to ensure RM integrity during storage; four other batches were sealed for long-term storage. The most accurate method of CO2 preparation for isotope mass spectrometry was used, namely carbonate-H3 PO4 reaction under controlled conditions. The assigned values of δ13 C = +2.460 ± 0.010‰ and δ18 O = -2.370 ± 0.040‰ (k = 1) are based on a large number of analyses (~10 mg aliquots) performed at IAEA and address all the known uncertainty components. For aliquots down to 120 μg, the δ18 O uncertainty remains unchanged but shall be doubled for δ13 C. The uncertainty components considered are as follows: (a) material homogeneity (within and between the 5200 ampoules produced), (b) value assignment against NBS19, (c) storage effects and (d) effect of the 17 O correction. The new primary RM IAEA-603 replaces NBS19 in its use as the highest calibrator for the VPDB δ13 C and δ18 O scale, including the VPDB-CO2 δ18 O scale. The use of IAEA-603 will allow laboratories worldwide to establish consistent realisation of the scales for δ13 C and δ18 O values and metrological comparability of measurement results for decades. The VPDB scale definition based on NBS19 stays valid.

Purity determination of pyributicarb by internal standard correction-high-performance liquid chromatography-quantitative nuclear magnetic resonance.

An internal standard correction-high-performance liquid chromatography-quantitative nuclear magnetic resonance (ISC-HPLC-qNMR) procedure was established as a reliable quantitative method for complex organic compounds with low purity in order to solve the risk of qNMR inaccuracy because of insufficient resolution of impurity peaks from the selected quantitative peak. This method collects a small quantity of target analyte from low-purity organics by LC. After drying and re-dissolving in deuterated solvent containing internal standard, the solution was analyzed by 1H NMR and HPLC. Another solution prepared by accurately weighing unpurified low-purity substance and internal standard was analyzed by HPLC. Based on the theoretical derivation derived from the Beer-Lambert law, using the ratio of the HPLC peak areas of two solutions as correction, the purity was then calculated without the same reference as target analyte. Compared to previous methods with similar selectivity and accuracy, it has advantages such as a less purified sample is required, time for lyophilization is reduced by half, and sample preparation is more controllable. The proposed method was verified by analysis of a suite of six commercially available, high-purity compounds, and the difference of results between it and direct qNMR was within 0.1%. The result of pyributicarb using ISC-HPLC-qNMR was 97.6% (U = 0.5%; k = 2), and the reference value was 97.61% (U = 0.22%; k = 2). The results demonstrate that the proposed method provides a new way for reference material producers to calibrate lower-purity organics and has the potential advantage of accurate quantification of lower-purity organics.

Further Steps Toward the Development of Gluten Reference Materials - Wheat Flours or Protein Isolates?

Celiac disease is a gluten-induced hypersensitivity reaction that requires a lifelong gluten-free diet. Gluten-free foods must not contain more than 20 mg/kg gluten as laid down by Codex Alimentarius. Measuring the presence of gluten with routine immunoanalytical methods in food is a serious challenge as many factors affect accurate determination. Comparability of the results obtained with different methods and method validation are hindered by the lack of a widely accepted reference material (RM). The core questions of RM development from wheat are the number of cultivars to be included and the format of gluten (i.e., flour, gluten, or gliadin isolates) to be applied. Therefore, the aim of our work was to produce an appropriate gluten RM from wheat. For this, five previously selected wheat cultivars and their blend were used to produce flours, gluten and gliadin isolates under laboratory conditions. Protein content, protein composition and responses to different ELISA methods were compared and widely evaluated in our study. The protein contents of the flours were 12.1–18.7%, those of the gluten isolates 93.8–97.4% and those of the gliadin isolates 72.7–101.9%. The gluten and gliadin isolates had similar protein profiles as the source flours. By comparing the different wheat cultivars and their protein isolates, we found that the isolation had a smaller effect on protein composition than genetic variability. The choice of a blend would be more suitable for the production of a RM in case of flours and also isolates. The immunoanalytical results showed that the isolation had an effect on the analytical results, but its extent depended on the ELISA method. The use of flour would be more applicable in this regard, but handling of the material and long-term stability should also be considered in the final decision of gluten RM production.

Spiking and homogenization of biological matrices for production of reference materials using cryogenic processes.

Biological reference materials (RMs) are essential for quality assurance, traceability of measurement results and for method validation. When addressing new measurement questions or emerging regulatory issues, rigorous large-scale CRM production may not be time efficient or economically practical using current production methods. By amending a relatively small matrix batch with a compound(s) of interest at the homogenization step, the National Institute of Standards and Technology (NIST) can create a custom material on an "as-needed" basis and circumvent the time delay inherent in large-batch production, thereby generating a fit-for-purpose, rapid-response RM. Here, Coho salmon (Oncorhynchus kisutch) was cryohomogenized and spiked with an aquaculture antibiotic and antibiotic metabolite. The resultant material was analyzed using liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) to determine the effectiveness of the amendment technique in a fresh-frozen matrix by assessing homogeneity and accuracy to the target concentration (e.g. mass fraction). Target mass fractions were achieved for both spike components, with RSDs below 5% in replicate measurements of each compound (n = 8). The stability of the spiked compounds was assessed oneyear post-production and mass fractions were stable, within 1-6% of the initial measurement results, indicating minimal change to the amended analyte concentrations over time. The results support this method as a promising new technique for custom, small-batch RM generation.

Types, Production and Validation of Reference Materials for Viral Genetic Testing

Types, Production and Validation of Reference Materials for Viral Genetic Testing

Characterisation and comparison of selected wheat (Triticum aestivum L.) cultivars and their blends to develop a gluten reference material

The reliability and comparability of gluten analytical results in gluten-free foods is hampered by the lack of reference materials (RM). This is partly caused by the yet incomplete knowledge of the effect of genetic and environmental variability of wheat proteins on immunochemical analyses, which affects the choice of gluten source to be applied for RM production. We investigated the genetic variability and the effect of harvest year on the protein composition of five previously selected wheat cultivars. We also compared the magnitude of these effects on ELISA results to get closer to the question of choosing individual cultivar or a mixture as an RM. Our results proved that the application of a blend for this purpose is advantageous. The candidates were also produced on pilot scale to investigate the feasibility of upscaling. The results of comparison studies showed that the pilot scale blended flour can also be suitable for RM.

Piezoelectric Micro-dosing System for Spiking Quality Samples in Occupational Hygiene Laboratories

Quality control is crucially important in the arena of chemical analysis. Reference materials are essential for calibration and quality control processes, and for verification of the accuracy and reliability of the analytical results obtained. Owing to the complexity of their manufacture, reference materials for chemical agents occurring at workplaces are expensive and available only on a limited scale and for a small number of substances. Therefore, their cost-effective and fast production is an important aim. The Institute for Occupational Health and Safety (IFA) of the German Social Accident Insurance (DGUV) currently pursues different strategies for the production of reference materials. One strategy entails the use of a piezoelectric micro-dispensing system for non-contact spiking of extremely small quantities of substances with high reproducibility. The dispensing system is coupled to a semi-automated assembly unit for loading high numbers of samples. It is used for spiking phosphoric and sulphuric acid onto quartz fibre filters. Comparison of the results obtained on different days shows higher variability than results observed on the same day. However, after daily adjustment of the number of droplets to the current droplet volume, highly reproducible series with an adequate number of samples (>500) could be realized. The results of the internal quality control were verified in an interlaboratory comparison. Furthermore, storage stability was investigated systematically over a period of 2 years. The samples produced are suitable for use as reference materials for both inorganic acids.

Systematic comparison of post-column isotope dilution using LC-CO-IRMS with qNMR for amino acid purity determination

Determination of the purity of a substance traceable to the International System of Units (SI) is important for the production of reference materials affording traceability in quantitative measurements. Post-column isotope dilution using liquid chromatography-chemical oxidation-isotope ratio mass spectrometry (ID-LC-CO-IRMS) has previously been suggested as a means to determine the purity of organic compounds; however, the lack of an uncertainty budget has prevented assessment of the utility this approach until now. In this work, the previously published ID-LC-CO-IRMS methods have not only been improved by direct gravimetric determination of the mass flow of 13C-labelled spike but also a comprehensive uncertainty budget has been established. This enabled direct comparison of the well-characterised ID-LC-CO-IRMS method to quantitative nuclear magnetic resonance spectroscopy (qNMR) for purity determination using valine as the model compound. The ID-LC-CO-IRMS and qNMR methods provided results that were in agreement within the associated measurement uncertainty for the purity of a sample of valine of (97.1 ± 4.7)% and (99.64 ± 0.20)%, respectively (expanded uncertainties, k = 2). The magnitude of the measurement uncertainty for ID-LC-CO-IRMS determination of valine purity precludes the use of this method for determination of purity by direct analysis of the main component in the majority of situations; however, a mass balance approach is expected to result in significantly improved measurement uncertainty.

Novel Bioprinting Application for the Production of Reference Material Containing a Defined Copy Number of Target DNA.

Nucleic acid amplification methods, such as polymerase chain reaction (PCR), are extensively used in many applications to detect target DNA because of their high sensitivity, good reproducibility, and wide dynamic range of quantification. However, analytical quality control when detecting low copy number target DNA is often missing because of a lack of appropriate reference materials. Recent advances in analytical sciences require a method to accurately quantify DNA at the single molecule level. Herein, we have developed a novel method to produce reference material containing a defined copy number of target DNA (referred to as "cell number-based DNA reference material"). In this method, a suspension of cells carrying a single target DNA sequence was ejected by an inkjet head, and the number of cells in each droplet was counted using highly sensitive cameras. The resulting solutions contained a defined copy number of target DNA and could be used as reference materials. The use of the newly developed reference material was compared with that of diluted solutions of target DNA to evaluate the performance of qualitative real-time PCR in terms of the limit of detection (LOD). Our results demonstrated that cell number-based DNA reference material provides more accurate information regarding performance quality. The reference material produced by this method is a promising tool to evaluate assay performance.

Desarrollo de un material de referencia certificado para análisis elemental de agua potable

La producción de un material de referencia (MR) es un proceso en el que se realizan estudios relacionados con la preparación, envasado y caracterización (incluye homogeneidad y estabilidad). En este trabajo se presentan los resultados del desarrollo de un MR de agua potable. El envasado se realiza aplicando dos procedimientos (envasado convencional e inmersión). La caracterización se realizó por Absorción Atómica, ICPMS y Cromatografía iónica. La evaluación de homogeneidad del material se realizó para Na, Mg, Ca, Fe, K, Co, Pb, Mo, As, Ni, Se, Cu, Al, Cr Zn y aniones como NO3-y Cl-. La estabilidad se evaluó a corto (condiciones aceleradas) y largo plazo por ICPMS y CI, además se realizó seguimiento gravimétrico. La homogeneidad y estabilidad se evaluaron con base en su incertidumbre. La incertidumbre asociada a la homogeneidad y estabilidad MR evidenció resultados aceptables para la mayoría de los analitos. Los resultados del seguimiento gravimétrico permitieron detectar pérdidas de masa del material, por lo que se planteó un nuevo esquema para evaluar la estabilidad a través de métodos gravimétricos. Finalmente, se encontró que el MR presenta incertidumbres expandidas entre el 0,93% y el 4,38%, siendo apto para el uso previsto.

Building Open Access to Research (OAR) Data Infrastructure at NIST.

As a National Metrology Institute (NMI), the USA National Institute of Standards and Technology (NIST) scientists, engineers and technology experts conduct research across a full spectrum of physical science domains. NIST is a non-regulatory agency within the U.S. Department of Commerce with a mission to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life. NIST research results in the production and distribution of standard reference materials, calibration services, and datasets. These are generated from a wide range of complex laboratory instrumentation, expert analyses, and calibration processes. In response to a government open data policy, and in collaboration with the broader research community, NIST has developed a federated Open Access to Research (OAR) scientific data infrastructure aligned with FAIR (Findable, Accessible, Interoperable, Reusable) data principles. Through the OAR initiatives, NIST’s Material Measurement Laboratory Office of Data and Informatics (ODI) recently released a new scientific data discovery portal and public data repository. These science-oriented applications provide dissemination and public access for data from across the broad spectrum of NIST research disciplines, including chemistry, biology, materials science (such as crystallography, nanomaterials, etc.), physics, disaster resilience, cyberinfrastructure, communications, forensics, and others. NIST’s public data consist of carefully curated Standard Reference Data, legacy high valued data, and new research data publications. The repository is thus evolving both in content and features as the nature of research progresses. Implementation of the OAR infrastructure is key to NIST’s role in sharing high integrity reproducible research for measurement science in a rapidly changing world.

Purity assessment using the mass balance approach for inorganic in-house certified reference material production at Inmetro

The production of Certified Reference Materials (CRMs) is one of the essential activities of the National Institute of Metrology, Quality and Technology (Inmetro) to ensure metrological traceability of inorganic elemental measurements in Brazil. This work presents a set of procedures for purity assessment and in-house certification of high-purity salts, implemented at the Laboratory of Inorganic Analysis, from the Chemical and Thermal Metrology Division at Inmetro. We developed and validated methodologies based on inductively coupled plasma mass spectrometry, energy-dispersive X-ray fluorescence spectrometry and inductively coupled plasma optical emission spectrometry measurements with standard addition calibration in order to determine the mass fraction of up to 71 elements considered as possible impurities. The purity of inorganic salts was determined using the mass balance approach with expanded measurement uncertainties smaller than a mass fraction of 0.007 %. All procedures were performed according to the ISO 17034:2016 standard. The CRMs will be used for the production and certification of single-element calibration solutions at Inmetro.

Complete dissolution of solid matrices using automated borate fusion in support of nuclear decommissioning and production of reference materials

Accurate measurement of natural and anthropogenic radionuclide concentrations is of critical importance to end users in the nuclear sector to ensure correct classification prior to storage, recycling, reprocessing or disposal. Uncertainties in the characterisation of solid matrices and materials could lead to safety, quality and financial implications. Robust sample preparation methods are vital, in particular effective sample digestion, as under-estimated chemical yield recovery results in a corresponding under-estimation of activity levels. Borate fusion has been proven to effectively digest a range of complex sample matrices in the geosciences but is not used routinely elsewhere. In this study, we describe an automated procedure for borate fusion of multiple matrices encountered in nuclear decommissioning, containing diverse radionuclides over a range of activity concentrations. The impact of digestion flux, sample mass and sample to flux ratios are described, as well as the subsequent separation and measurement techniques. The results contribute to accurate and precise measurement of radionuclides in various matrices, as well as to characterisation of reference materials, providing greater confidence in nuclear industry programmes worldwide.

Advances in reference materials and measurement techniques for greenhouse gas atmospheric observations

We present the global research landscape which aims to deliver a measurement infrastructure to underpin atmospheric observations of key greenhouse gases governing changes in the Earth’s climate. These measurements present a significant challenge to the metrological community, analytical laboratories and major producers of reference materials. The review focuses on the progress made in the Gas Analysis Working Group of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM-GAWG) in establishing the primary realisation of the amount-of-substance fraction for carbon dioxide, methane and nitrous oxide in an air matrix. It also focuses on the importance of providing traceable measurements of isotopic composition of these components for commutability of reference materials and for isotope ratio measurements for greenhouse gas source attribution. The review examines the developments in the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) for providing the framework for the development and implementation of integrated greenhouse gas observations, which is vital for understanding the global carbon cycle and the role greenhouse gases play in climate change. The developments in analytical techniques are also discussed which have shaped the direction of the metrology required to meet the evolving and future needs of stakeholders.

Development and validation of two triplex real-time PCR systems for the simultaneous detection of six cereal species in processed meat products

Meat protein can be substituted by plant protein in meat products, and cereals are particularly well-suited for this purpose as they are high in protein content and have good bioavailability. The aim of the present work was to develop real-time PCR assays for the detection and quantification of the six most commonly used cereals barley, oat, rye, maize, rice, and wheat in processed meat products. Emulsified sausages were produced with cereal flours (0.0005–0.1%). Additionally, the effect of different post-processing methods (grilling or storage), packaging materials (cans and artificial sausage casings), and cooking temperatures (75 °C, 117 °C, and 121 °C) were investigated. A negative influence on the detectability of DNA was observed with increasing cooking temperature. All other production parameters showed no significant effect. The limit of quantification was as low as 5 ppm of plant protein for all production conditions, which corresponded to 36–58 mg flour per kg of sausage. The validation of the production of reference material was more accurate for the sausages produced at low than at medium temperatures.Overall, the two triplex real-time PCR systems can be applied for specific, sensitive, and simultaneous detection of these six cereal species in meat products. However, the reference material for quantification has to be carefully chosen due to the negative influence of heat treatment on the detectability of DNA.

Droplet Volume Variability and Impact on Digital PCR Copy Number Concentration Measurements.

Digital polymerase chain reaction (dPCR) is increasingly being adopted by reference material producers and metrology institutes for value assignment, and for homogeneity and stability studies of nucleic acid reference materials. A reference method procedure should fulfill several requirements, and the uncertainty and biases should be completely understood. A bias in target concentration when inaccurate droplet volume is used in the droplet dPCR measurement equation has previously been documented. In this study, we characterize both intrawell and interwell droplet volume variability using optical microscopy and determine the impact of these two sources of variability on target concentration estimates. A small optical distortion across the image was measured which, without correction, biased droplet volume measurements. Longitudinal monitoring of interwell droplet volume over 39 weeks using several lots of Mastermix demonstrated a mean droplet volume of 0.786 nL and intermediate precision of 1.7%. The frequency distribution of intrawell droplet volumes varied. Some wells displayed a skewed distribution which resulted in a small bias in estimated target concentration for a simulated dPCR with target concentrations of between 62 and 8000 copies μL-1. The size and direction of this bias was influenced by the distribution pattern of the droplet volumes within the well. The proportion of Mastermix in dPCR mix affected droplet volume. A pipetting error of 10% during mixing of the premix and Mastermix resulted in a 2.6% change in droplet volume and, consequently, a bias in concentration measurements highlighting the advantages of gravimetric preparation of dPCR mixes for high accuracy measurements.

Reference materials in the system of metrological assurance of quantitative analysis

This publication gives brief information about the system of reference materials (RM) in the Russian Federation, particularly in the field of legal and regulatory support for the production and use of RM. The role of the State service for reference materials of composition and properties of substances and materials is discussed along with the components of state regulation in view of formation of the national market of reference materials. The aspects of «search» for RM that are necessary for implementation of the measurement tasks assigned to the laboratory are shown. The information about large producers of RM in metallurgy, nuclear energy and geology is presented.

Data integrity: requirements set in the accreditation standards

The requirements for the competence of laboratories are described in two standards, namely ISO/IEC 17025 and ISO 15189. The former applies to all laboratories except medical laboratories where the latter is the most appropriate. The requirements of both standards include specific references to data and other related terms, their protection and integrity. The recently revised ISO/IEC 17025 introduces additional provisions for the control of data and information management compared to those of the 2005 edition. Both standards include provisions for the use of laboratory information management system(s) for the collection, processing, recording, reporting, storage or retrieval of data. ISO 15189 addresses these issues in more detail in order to meet the particular needs of the sector dealing with personal data of the patients. This article presents the requirements for data integrity and the control of relevant components of the management system set by the standards for laboratories as well as for some other conformity assessment bodies of importance for laboratory work, namely reference materials producers (ISO 17034) and proficiency testing providers (ISO/IEC 17043). Some additional regulatory requirements recently implemented are also discussed.