Production Of Reference Materials Research Articles

Production and application of reference materials for high containment RNA viruses

Production and application of reference materials for high containment RNA viruses

Use of Pseudotyped viruses for the production of reference materials as part of emerging viral outbreak preparedness

Purpose: The recent public health emergencies of international concern (PHEIC), caused by Ebola and Zika virus, have highlighted the lack of prophylactic treatments and need for effective diagnostics for emerging viruses. In response to this, we established International Reference Reagents for antibody detection, which enables the comparison of results from laboratories worldwide undertaking treatment/vaccine efficacy clinical trials. The requirement for high containment facilities to handle viruses with outbreak potential, such as BSL4 for Ebola virus, is a constraining challenge. We have developed serological assays using replication defective pseudotyped viruses (PV) for the evaluation of reference material to avert high containment requirements. Methods & Materials: The preferred candidate material is a pool of plasma or sera from convalescent patients as this provides a commutable standard. For the reference material for Ebola antibody, several donations were received at NIBSC and solvent-detergent treated to ensure inactivation of virus. Characterisation is performed in-house using both PV neutralisation assays and ELISA platforms. PV is produced via plasmid transfection of 293T cells, with plasmids encoding a lentiviral core component, a reporter gene which is packaged within the core and the sequence of the envelope protein for the virus of interest. The ability of candidate material to block PV entry into target cells is measured via reporter signal reduction. Results: Following a WHO-sponsored International Collaborative study, the 1st WHO International Standard for Ebola virus antibodies was established in 2017. Participants in the collaborative study evaluated the candidate materials using assays available in their laboratories. Data from neutralisation assays employing PV with either a lentiviral or vesiculoviral core component was correlated with the wildtype assay and showed a better correlation coefficient when the vesiculovirus PV system was used. Conclusion: To support preparedness activities, antibody reference materials are now being established for other WHO priority pathogens such as Lassa and Nipah virus. To characterise the serological material at a low containment level, we have established assays using PV generated with both the lentiviral and vesiculovirus platforms. The two systems are currently being investigated to determine the most appropriate for each high containment virus.

Principles for the characterisation and the value assignment of the candidate reference material in the new ISO Guide 35:2017

The production of reference materials (RMs) is a key activity for the improvement and maintenance of a worldwide coherent measurement system. General requirements for the production of all types of RMs are set out in ISO 17034:2016. These general requirements include a characterisation strategy with a note that references the list of approaches that are discussed in more detail in the new ISO Guide 35:2017. This paper provides an overview of the characterisation approaches explained in technical detail in the new ISO Guide 35:2017, with particular attention being paid to changes from the 2006 edition. Important changes include a clear distinction between the use of a single method in a single-laboratory approach when the method can be validated with a certified reference material (CRM) of the same kind as the candidate reference material compared to when a similar CRM is not available. For the approach where more than one method is used in one or more laboratories, the concept of the importance of the number of independent data sets is explained in more detail. A lot more technical detail is also provided for the use of an interlaboratory comparison for the certification study.

Reference materials of the new grades of nickel superalloys and their use in spectral analysis

Development of rapid method of spectral analysis capable of accompanying all the stages of nickel superalloy production is a hot topic of the analytical control of nickel superalloys. To ensure high accuracy of the results obtained by the methods of optical emission spectrometry and X-ray fluorescence spectrometry, reference materials (RM) adequate in composition to the analyzed samples are to be used. The lack of RM for novel grades of modern nickel alloys, entails the necessity of their development and certification. A methodical approach to the development and production of RM of new grades of nickel superalloys is presented. It is shown that production of the corresponding RM for spectral analysis apart from obvious requirement regarding the absence of defects (shells, cracks, nonmetallic inclusions, isolated zones differing in the content of alloying elements and impurities) requires also elimination of the areas of increased microporosity. In this case, the samples are rejected and melted down, the smelting modes of the CO blanks being adjusted if necessary. We have studied the structure and homogeneity of the manufactured RM and determined the certified values of the reference materials for nickel superalloys of the type VZhM, VKNA, etc. The potentiality of using the developed RM for optical emission spectroscopy with spark excitation and X-ray fluorescence analysis are considered. It is shown that optical emission spectroscopic analysis with spark excitation requires RM sets most close in composition to the analyzed samples when plotting a calibration characteristic, whereas when using X-ray fluorescence analysis, combined sets of RM are appropriate for analysis of the alloy grades similar in composition. The metrological characteristics of the reference materials of approved types (certified reference materials) for the spectral analysis developed at FSUE VIAM for the last seven years are presented.

CCQM-K95.1 Low-polarity analytes in a botanical matrix: polycyclic aromatic hydrocarbons (PAHs) in tea

Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 “Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea”. This was a follow-on comparison from CCQM-K95 which was completed in 2014.The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.KEY WORDS FOR SEARCHbenz[a]anthracene (BaA), benzo[a]pyrene (BaP), gas chromatography(GC), isotope dilution (ID), liquid chromatography (LC), mass spectrometry (MS), polycyclic aromatic hydrocarbon (PAH), yerba mate teaMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Preparation and characterization of in-house reference material for four organochlorine pesticides in tea matrix

Production and evaluation of in-house reference material for incurred residues of four organochlorine pesticides, named hexachlorobenzene, dicofol, pp′-DDE, and op′-DDT, in tea sample has been performed. Raw materials (tea samples) were confirmed to contain certain levels of incurred organochlorine pesticide residues by a validated gas chromatography–mass spectrometry method. After the materials had been milled and thoroughly mixed, 400 bottles each having 20 g sample were prepared and their homogeneity (within-bottle and bottle-to-bottle variation) was found to be sufficient. The materials demonstrated satisfying stability of four organochlorine pesticides in both short-term (30 days) and long-term (12 months) stability studies. The reference values were characterized using an accurate isotope dilution gas chromatography–mass spectrometry method. The mass fraction (± expanded uncertainty) of hexachlorobenzene, dicofol, pp′-DDE, and op′-DDT in the reference material was (2.1 ± 0.2) mg kg−1, (513.3 ± 31.3) mg kg−1, (8.3 ± 0.6) mg kg−1, and (14.9 ± 1.0) mg kg−1, respectively. The reference materials have been distributed for use in laboratory quality assurance.

PRIMARY STANDARDIZATION OF THE MASSIC ACTIVITY OF A PROTACTINIUM-233 SOLUTION.

Protactinium-233 (233Pa) is used as a tracer for radiochemical analysis and is of particular interest as an isotope dilution mass spectrometry (IDMS) spike for 231Pa/235U radio-chronometry. To this end, we present massic activity determinations by two methods for a 233Pa solution, which was prepared at Lawrence Livermore National Laboratory (LLNL) and is being characterized at multiple labs as part of a 231Pa reference material production project. One activity determination method was 4πβ-γ anti-coincidence counting in a multi-dimensional extrapolation model, with Monte Carlo corrections. An independent massic activity determination was completed by γ-ray spectrometry using 5 HPGe detectors using 5 γ-ray lines. The anti-coincidence and γ-ray spectrometry results agree and have combined standard uncertainties of about 0.33 % and 1.0 % respectively. In addition, the two methods were combined to derive γ-ray emission probabilities from 233Pa decay.

Uranium oxide microparticle suspensions for the production of reference materials for micro-analytical methods

To support the nuclear safeguards particle analysis, a method was developed to produce micrometer-sized uranium oxide microspheres with a known uranium content and isotope ratio, which are intended to be characterized as certified reference material. To simplify handling of the produced particles, the collected particles have been transferred into ethanol suspensions. In addition to a demonstration of the suitability and new capabilities of such particle suspensions, such as the preparation of particle mixtures, the stability of the particles has been investigated and demonstrated with regard to dissolution and isotopic exchange.

METROFOOD-RI: a new reality to develop Reference Materials for the agrifood sector

METROFOOD-RI is a new Research Infrastructure (ESFRI Domain “Health & Food”) aimed at promoting metrology in food and nutrition constituted by an organised network of physical and electronic facilities allowing to perform cross-cutting research activities and deliver advanced services addressed to different categories of users: research/academy, food inspection and control agencies/policy makers, food business operators, consumers/citizens. Among the core-services of METROFOOD-RI, there is the development and production of new (certified) Reference Materials (RMs). The RI includes in fact - among its physical facilities – an integrated network of plants and laboratories specialised in the production and characterisation of new RMs for the agrifood sector. As further added value, thanks to its network of experimental fields, farms and pilot production plants, METROFOOD-RI is also able to produce the raw materials to be used for preparing the RMs themselves and therefore, so being able to realize customized RM perfectly meeting the user’s needs. The capability of producing food matrix RMs has been recently tested during the “Early Phase” of METROFOOD-RI (H2020 INFRADEV-02-2016 PRO-METROFOOD, G.A. 739568), by implementing a specific pilot service dedicated to the development and characterization of new RMs of rice grains, rice flour and oyster tissue.

National market of reference materials. Curreent state, problems, and development prospects. Part 1. Introduction. Development of the national market of reference materials

The present publication begins a cycle of papers of specialists from the Scientific Methodical Centre at the State Service of Reference Materials for Composition and Properties of Substances and Materials. These papers will be devoted to the problematic issues of forming and developing the national market of reference materials in terms of requirements imposed by the current legislation of the Russian Federation concerning of measurement uniformity assurance, technical regulation and accreditation in the national accreditation system. Publications are aimed at giving the reader an insight into the common practice of development and use of reference materials of various categories, state regulation procedures when producing and using reference materials taking into account modern requirements in the field of metrological assurance and measurement uniformity in Russia and abroad, together with necessity and importance of harmonization in the field of reference materials, as well as some other aspects of this activity. This paper discusses main aspects concerning the state of the reference materials market in the Russian Federation and suggestions on its development taking into account modern requirements. The role of state regulation when creating the national market of reference materials in the Russian Federation is shown. The paper specifies possible directions for reference materials production, meeting modern metrological requirements imposed on measurements in the sphere of the state regulation of measurement uniformity assurance.

Measurement uncertainty: requirements set in the accreditation standards

Measurement uncertainty is of high importance to all testing and calibration laboratories and those involved in sampling activities. Its evaluation requires good understanding of the method implemented and realisation of all factors contributing to it. It is required that the users of the results fully understand the meaning of uncertainty stated on test reports and calibration certificates and, when needed, ask for clarifications. Laboratories, both the accredited ones and those being prepared towards their accreditation, need to take this into account when evaluating the uncertainty of their results. Competent authorities need to consider the stated uncertainty to compare the result with a legislative limit. The producer can decide on adjustments needed. The consumer may find it more difficult to understand how this “uncertain component” of the results could affect their health, safety or economic rights. This article describes the relevant requirements of the accreditation standards referring both to testing and calibration laboratories and to proficiency testing and reference material producers. Further to this, the article explains why all these factors have to be considered by a laboratory.

DEVELOPMENT OF REFERENCE MATERIAL OF HOLMIUM OXIDE FOR SPECTROMETERS WAVELENGTH CALIBRATION: FEASIBILITY STUDIES

The use of certified reference material (CRM) in chemical analyzes is an important requirement in quality assurance systems, since it allows the metrological traceability of results, thus achieving valid and comparable results. This work describes the development and production of holmium oxide reference material that, after certification, will be used in the calibration of the wavelength range of UV-Vis spectrometers and also the necessary feasibility studies to establish the measurement parameters to be used in the next steps of the material production and certification.

THE INSTITUTE FOR CERTIFIED REFERENCE MATERIALS MARKS THE 55TH ANNIVERSARY OF FOUNDATION. DEVELOPMENT AND PRODUCTION OF CERTIFIED REFERENCE MATERIALS FOR METALLURGICAL PRODUCTION

The Institute for Certified Reference Materials (ICRM) is going to celebrate the 55 th anniversary in March 2018. The results of the ICRM activities in development and production of the certified reference materials (CRM) of raw materials and materials of metallurgical production over the past five years are considered. The nomenclature of the CRM produced by the ICRM includes raw materials (ores and concentrates, ferroalloys and ligatures, fluxes, refractories), metals (cast iron, steel, nickel-base alloys) and waste of metallurgical production (slags and metallurgical fly ashes). To approve the competence, the ICRM has been accredited as a producer of reference materials (RMP) in accordance with the requirements of the International Standard ISO Guide 34:2009 (ISO Guide 34). Testing analytical center of the ICRM (TC) applies both classical methods of chemical analysis (methods of «wet chemistry») and modern physicochemical and physical methods. TC is accredited in accordance with GOST ISO/IEC 17025 – 2009 in the National accreditation system. The competence of Testing Centre has been repeatedly approved by the results of inter-laboratory comparative tests for certification of reference materials produced abroad including those from the European Union (ECRM). The inter-laboratory tests (proficiency tests — PT) are performed by the Provider, ICRM accredited in the National Accreditation System for compliance with the requirements of GOST ISO/IEC 17043:2013. We consider and analyze contradictions in the statutory regulation and resulting difficulties encountered in the activities of producers of reference materials in Russia. The approval of reference materials to be used in the state system for ensuring the uniformity of measurements is possible only on the basis of positive test results. This procedure (RM testing for type approval purposes) has no analogues in the world practice. In accordance with the Russian legislation, the ICRM has got accreditation to perform RM testing for the type approval purposes in 2015. In 2013 – 2017 the Institute developed and certified 7 CRM sets of steel and 3 CRM sets of cast iron for spectral analysis (solids), and 46 CRM for chemical analysis (in dispersed form), including carbon and alloyed steel, cast iron, ferroalloys, ore and concentrates, metallurgical slags.

Large-scale Cultivation of Gymnodinium Catenatum for Paralytic Shellfish Poisoning Toxin Standards.

An adequate supply of standard reference material for paralytic shellfish toxins (PSTs) is critical for the accurate chemical quantification using high performance liquid chromatography (HPLC) with fluorescent detection, liquid chromatography-tandem mass spectrometry (LC-MS/MS), biological analysis of these toxins using enzyme-linked immunosorbent assay (ELISA), and immunochromatography. Large batch cultivation for the chain forming species G. catenatum, producers of PSTs of N-sulfocarbamoyl-11-hydroxysulfate toxins (C1 and C2), gonyautoxin 5 (GTX5) and gonyautoxin 6 (GTX6), was investigated using 10 L round-bottom flasks with aeration for the production of GTX5 and GTX6. Aeration rates of 200 mL/min and 500 mL/min were compared, demonstrating that the 500 mL/min aeration rate was adequate to eliminate aggregation of cells. The highest cell density of G. catenatum in 500 mL/min aeration treatment was 9,878 ± 2,617 cells/ml on day 28. Total toxin yield during 10 L cultivation with 500 mL/min aeration was calculated at 30.9 ± 3.6 µmol on day 25, with GTX5 and GTX6 calculated at 3.9 ± 0.7 µmol and 11.4 ± 1.4 µmol, respectively. This simple aeration method will contribute to the more efficient production of PST reference materials.

Bayesian analysis of homogeneity studies in the production of reference materials

For almost two decades, the batch homogeneity in the production of reference materials has been evaluated using analysis of variance (ANOVA) to determine the between-bottle standard deviation. This approach replaced at that time the use of the F-test in ANOVA to determine whether the ratio of the mean squares $${MS}_{\mathrm {between}}/{MS}_{\mathrm {within}}$$ is statistically significant. Problems arise when $${MS}_{\mathrm {between}} < {MS}_{\mathrm {within}}$$ , because classical ANOVA provides a negative between-bottle variance, which is then often set to zero. By using a Bayesian hierarchical model, based on the same assumptions as traditional ANOVA, we show that even if $${MS}_{\mathrm {between}} < {MS}_{\mathrm {within}}$$ , there can be a relevant level of between-bottle inhomogeneity to account for. The Bayesian analysis produces a nonzero value for the between-bottle standard deviation, which dismisses the practice of setting this standard deviation to 0. At the same time, it dismisses the current guidance given in ISO Guide 35 under these circumstances. Finally, it is shown that traditional ANOVA, meta-analysis methods and Bayesian analysis give very similar answers as long as $${MS}_{\mathrm {between}} > {MS}_{\mathrm {within}}$$ , so there is no need to discourage using these methods in favour of a Bayesian analysis, provided that the repeatability of the measurement method used to conduct the between-bottle homogeneity study is sufficient to characterise the dispersion across the bottles (items) in a batch of a reference material.

Certified reference material production in Turkey

Certified reference material production in Turkey

Principles for the assessment of homogeneity and stability in the new ISO Guide 35:2017

The production of reference materials (RMs) is a key activity for the improvement and maintenance of a worldwide coherent measurement system. General requirements for all types of RM production are set out in ISO 17034. These general requirements include the assessment of homogeneity and stability. Technical detail is, however, left entirely to other guides, of which ISO Guide 35 is the most general and comprehensive. This paper provides an overview of the provisions for stability and homogeneity assessment in ISO Guide 35:2017, with particular attention to changes from the 2006 edition. Important changes include new guidance on the need for experimental studies when substantial prior experience is available; a larger range of homogeneity study designs; improved guidance on the use of accelerated stability studies; additional, and more flexible, guidance on within-unit homogeneity assessment; greater attention to post-certification monitoring; and new provisions for end-user storage and repeated sampling from individual RM units.

Optimizing High-Resolution Mass Spectrometry for the Identification of Low-Abundance Post-Translational Modifications of Intact Proteins.

Intact protein analysis by liquid chromatography-mass spectrometry (LC-MS) is now possible due to the improved capabilities of mass spectrometers yielding greater resolution, mass accuracy, and extended mass ranges. Concurrent measurement of post-translational modifications (PTMs) during LC-MS of intact proteins is advantageous while monitoring critical proteoform status, such as for clinical samples or during production of reference materials. However, difficulties exist for PTM identification when the protein is large or contains multiple modification sites. In this work, analyses of low-abundance proteoforms of proteins of clinical or therapeutic interest, including C-reactive protein, vitamin D-binding protein, transferrin, and immunoglobulin G (NISTmAb), were performed on an Orbitrap Elite mass spectrometer. This work investigated the effect of various instrument parameters including source temperatures, in-source CID, microscan type and quantity, resolution, and automatic gain control on spectral quality. The signal-to-noise ratio was found to be a suitable spectral attribute which facilitated identification of low abundance PTMs. Source temperature and CID voltage were found to require specific optimization for each protein. This study identifies key instrumental parameters requiring optimization for improved detection of a variety of PTMs by LC-MS and establishes a methodological framework to ensure robust proteoform identifications, the first step in their ultimate quantification.

Development of milk powder reference material and its use for evaluation of laboratory performance on analysis of mandatory nutrients for nutrition labelling in Thailand

This study investigated the laboratory performance on the analyses of mandatory nutrients for nutrition labelling in Thailand and aimed to upgrade the proficiency test (PT) material into a reference material (RM). This milk powder with sufficient homogeneity and multiple nutrient compositions provided an acceptable PT material. Twenty ISO 17025 accredited laboratories participated in this study, and analytical performance was investigated using ISO 17043 and ISO 13528 standards. Satisfactory performance (|z| ≤ 2, for both within- and between-laboratory variations) was found among participating laboratories on the analyses of total fat, saturated fat, cholesterol, protein, sugar, sodium, vitamin B1, vitamin B2, calcium, iron, moisture, and ash. The values of these nutrients (mean and standard deviation) were applied to upgrade the PT material to be used as a reference material. For a trial, moisture, vitamin B1, and vitamin B2 were selected as three representative nutrients to develop reference values as mean and uncertainty following ISO Guides 34 and 35 for RM production. The mean of moisture, vitamin B1, and vitamin B2 values of 2.34 g/(100 g), 0.64 mg/(100 g), and 0.78 mg/(100 g) were obtained with the relative expanded uncertainty of 12.2 %, 12.7 %, and 9.7 %, respectively. The developed RM can be used as quality control sample or as PT material with reference nutrient values among the laboratories in Thailand.

Variation in protein composition among wheat (Triticum aestivum L.) cultivars to identify cultivars suitable as reference material for wheat gluten analysis

Gluten proteins of certain cereals (wheat, rye and barley) can trigger hypersensitivity reactions. In special dietary products for people intolerant to gluten, their amount must not exceed the regulatory threshold levels. The source of gluten can influence gluten quantitation due to variability in protein profile of grain cultivars and species. A proper reference material is crucial for accurate measurement of gluten and evaluating assay performance. It should be as representative of the commodity as possible. In this study, protein content and composition of a set of 23 common wheat cultivars grown around the world were determined. According to qualitative and quantitative selection criteria, cultivars that possessed a typical gluten composition were identified. Five cultivars were selected for subsequent experiments to confirm their suitability as a basis for reference material production.