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Ocean alkalinity (A T) critically affects the buffering capacity and the precipitation and dissolution of calcium carbonate minerals in the ocean. However, our knowledge of A T is still incomplete because of limited investigations into the contributions of dissolved organic matter (DOM) to alkalinity (A DOM) across diverse ocean environments. Here, to improve the accuracy of seawater A DOM measurements, we have implemented three key modifications to the conventional method based on a second-HCl-titration. These modifications include: (1) determining concentrations and pK spectra of A DOM using the same NaOH-titration data; (2) routinely evaluating residual alkalinity (A C redidual) remaining in seawater; and (3) validating the accuracy of A DOM against known concentrations of acetate ions in sodium acetate (CH 3 COONa) solution, where only acetate ions contribute to A DOM. In experiments involving modification (3), the A DOM values obtained through NaOH-titration agreed with those obtained through standard HCl titration, showing an average difference of −0.4 ± 2.7 μmol kg−1. Modification (3) represents a critical improvement incorporated into the NaOH-titration method proposed here and can also improve the accuracy of A DOM obtained by the conventional second-HCl-titration method. Modification (2) would also enhance the A DOM accuracy because the uncertainty in A C residual can be directly translated into A DOM values. When applied to certified reference materials for A T and C T , aged local seawater, and deep waters of the East Sea, the NaOH-titration method consistently yielded A DOM values approximately 5 μmol kg−1 higher than those obtained for artificial seawater containing zero A DOM. This small yet significant A DOM value was attributed to the recalcitrant DOM component, which is widespread in the global ocean. [ABSTRACT FROM AUTHOR]

The use of reference materials (RMs) and certified reference materials (CRMs) is essential to guarantee the reliability of measurement procedures ‐ a major factor motivating the efforts of the geoanalytical community. This work quantifies trends and patterns in the scientific literature concerning RMs and CRMs in geochemistry for specific timespans, with the aim of evaluating historical developments, research fields, geographic shifts of research centres, and current trends. The Scopus database was surveyed for peer‐reviewed full‐texts (14,201 documents), which were subsequently exploited for statistical description, bibliometric mapping and cluster analysis. Mineral exploration and trace element geochemistry stimulated early research, whereas environmental subjects have grown in importance mainly since the year 2000. International standardisation was coincident with an increase of publications covering CRMs and geochemistry, and is thought to reflect the impact of ISO guidelines in this scientific activity. Other factors include investments in research facilities, creation of specialised geoanalytical journals and organisation of international meetings. The analysis shows that RMs are typically used for petrogenetic research topics, whereas CRMs are equally important for environmental sciences, chemistry and geosciences. Environmental sciences are mostly concerned with anthropogenic contamination of ecosystems by heavy metals, whereas geological interest is mainly driven by isotope geochemistry. Scientific frontiers in geoanalytical research comprise microanalytical methodologies, unconventional isotopes, rare earth elements and environmental monitoring. New trends in CRM applications also include biogeochemistry and radionuclides. [ABSTRACT FROM AUTHOR]

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This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were determined in interlaboratory tests. All results were assessed statistically for outliers. The results from three or more independent and different analytical methods were used for the calculations. In parallel homogeneity, the stability, and characterization standard uncertainties were calculated and used in the estimation of the final expanded uncertainties of the certified values. Finally, four new CRMs were assisted with the proper certificates according to ISO standards. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of N-{2-[4-(β-d-Glucopyranosyloxy)-2-methylphenyl]-1,1-dimethyl-2-oxoethyl}-3-methylthiophene-2-carboxamide (GPTC), a metabolite of the fungicide isofetamid. The authors describe the importance of certified reference materials (CRMs) for accurate analysis of toxic chemicals in food. They report a decagram-scale synthesis of GPTC to obtain a standard CRM for residue analysis in food. The synthesis involves several steps, including protection, amination, coupling, and glycosylation, resulting in the production of 25 grams of GPTC with a purity of 99.6%. The authors conclude that this synthetic approach can be used to establish a standard CRM for analyzing residues in food. [Extracted from the article]

Abstarct: Co(II), Cu(II), Ni(II), and Zn(II) ions from food and water sample have been separated and preconcentrated using a novel, straightforward, and precise carrier element-free coprecipitation approach. The suggested procedure relied on the utilization of 4-(5‑bromo-2-hydroxybenzylideneamino)-N-(pyrimidin-2-yl)-benzenesulfonamide (BHBAPBS) as a novel co-precipitant at neutral medium and the flame atomic absorption spectrometry identification of the studied metal ions under investigation. To obtain the metal ions for analysis, Several variables, like pH, volume of the sample, co-precipitant amount, and the speed and duration of centrifugation, were examined for their effects. The impact of coexisting ions was also being watched, but no interferences were discovered. The validity of the recommended strategy was examined using tests using certified reference materials. Analyte ion recovery values were calculated and found to be between 95 and 100 %. To assess the reliability of the suggested approach, the relative standard deviation was calculated and discovered to be 3.5 %. The detection limits were ranged between 0.3 and 0.6 μg L−1. Preconcentration factor has been determined to be 100. Results for the preconcentration and separation of trace levels of the investigated ions in environmental and certified reference materials samples were satisfactory.

Vinyl acetate is a restricted substance in food products. The quantification of the organic impurities in vinyl acetate is a major problem due to its activity, instability, and volatility. In this paper, while using the mass balance method to determine the purity of vinyl acetate, an improved method was established for the determination of the content of three impurities in vinyl acetate reference material, and the GC-FID peak area normalization for vinyl acetate was calibrated. The three trace organic impurities were identified by gas chromatography tandem high-resolution mass spectrometry to be methyl acetate, ethyl acetate, and vinyl propionate. The content and relative correction factors for the three organic impurities were measured. The purity of vinyl acetate determined by the mass balance method was 99.90% with an expanded uncertainty of 0.30%, and the total content of organic impurities was 0.08% with a relative correction factor of 1.23%. The vinyl acetate reference material has been approved as a national certified reference material in China as GBW (E) 062710. [ABSTRACT FROM AUTHOR]

The National Centre for Compositional Characterisation of Materials (NCCCM) / Bhabha Atomic Research Centre (BARC) and National Aluminium Company Limited (NALCO), India have produced an Indian origin bauxite certified reference material (CRM), referred to as BARC‐B1201, certified for major (Al2O3, Fe2O3, SiO2, TiO2, loss on ignition ‐ LOI) and trace contents (V2O5, MnO, Cr2O3, MgO). Characterisation was undertaken by strict adherence to ISO Guides. A method previously developed and validated in our laboratory, using single step bauxite dissolution and subsequent quantitation (of Al2O3, Fe2O3, SiO2, TiO2, V2O5, MnO, Cr2O3 and MgO) by ICP‐AES (SSBD ICP‐AES) was used for homogeneity studies and an inter‐laboratory comparison exercise (ILCE) of the candidate CRM. LOI was determined by thermo‐gravimetric analysis. Property values were assigned after an ILCE with participation from seventeen reputed government and private sector laboratories in India. The CRM was certified for nine property values: Al2O3, Fe2O3, SiO2, TiO2, V2O5, MnO, Cr2O3, MgO and LOI, which are traceable to SI units. [ABSTRACT FROM AUTHOR]

Due to an absence of domestic certified reference materials for coal on the Polish market, an attempt was made to manufacture a new and innovative product tailored to its needs. The chosen candidate material was hard coal acquired from Poland’s coal mines. A single reference material unit consisted of 50g of an analytical hard coal sample with a grain size below 0.2 mm. A manufacturing method was developed enabling production of matrix reference materials addressing the needs of the domestic solid fuel market, and was directed at research laboratories carrying out analyses of solid fuels for the energy and coking sectors. The adapted manufacturing scheme of a certified reference material for coal was presented with a description of the chosen critical steps of the process and discussion of the obtained results in terms of homogeneity, stability, characterisation of the reference material as well as assigned values to particular properties and their uncertainty budget. The results obtained during homogeneity, short-term and long-term stability assessments as well as reference material characterisation confirmed the feasibility of the investigated certified coal reference material manufacturing process. The obtained levels of relative expanded uncertainties of the measurements confirmed the feasibility of the manufactured certified reference material for establishing and maintaining metrological traceability of measurement results. The presented research establishes a base for planning out production of additional reference materials as well as providing the know-how for designing manufacturing schemes for reference materials for solid fuels, or waste related materials like fly ash, or furnace waste.

The relevance of the study is caused by the need to develop methodological solutions for the quantitative determination of gold content in ferromanganese formations and other geological objects due to the chemical and analytical difficulties that exist here and the insufficient number of certified reference materials of ferromanganese formations with a reliably certified gold content in them. The main aim is verification of the applicability of the gold extraction technique using petroleum sulfides (dibutyl sulfide in toluene) for determining gold in ferromanganese formations with electrothermal atomic absorption termination, along with the gold extraction method by its co-precipitation with tellurium. Objects: samples of ferromanganese formations from various regions of the North Pacific Ocean, as well as the Russian certified reference materials with a certified gold content OOPE 603 (SDO-6) and the USGS standard NOD-A-1. Methods. Gold was concentrated during its determination in ferromanganese formations by the methods of extraction with dibutyl sulfide in toluene and co-precipitation with tellurium and electrothermal atomic absorption analysis. Processing of the obtained results was carried out using the methods of mathematical statistics. Results. The method of gold extraction with dibutyl sulfide in toluene has shown its advantage for the purposes of analysis of ferromanganese formations in comparison with the procedure of co-precipitation with tellurium, due to its high selectivity, which makes it possible to get rid of the influence of matrix components, primarily iron, which forms an interfering superposition of spectral lines during atomic absorption determination of gold. The technique of gold extraction with dibutyl sulfide was tested for the analysis of ferromanganese formations samples from various regions of the North Pacific Ocean, as well as for the analysis of ferromanganese formations samples – the Russian OOPE 603 ​​(SDO-6) and the American standard NOD-A-1. The use of an air-dry sample of 2 g of the sample gave a satisfactory result in the analysis of the standard sample SDO-6, with a certified gold content of 10±6 ng/g, but did not allow successful analysis of the NOD-A-1 sample, for which irreproducible results were obtained. In this regard, the use of even larger weights is recommended for defining gold in this standard. Atomic absorption determination of gold in the studied ferromanganese formations samples using the proposed method gave results that meet the requirements of geochemical analysis, including in comparison with the ICP-MS method. However, an earlier electron microscopic study of ferromanganese crusts in the northwestern part of the Pacific Ocean showed the presence of native gold particles in them, which, in its turn, can cause methodological difficulties in the process of taking a representative sample and the procedure for preparing ferromanganese formations samples for analysis.

Abstract Multivitamin tablet certified reference material (CRM, 108-10-019) was developed for the analysis of seven water-soluble vitamins, including thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxine, biotin, and folic acid. The CRM was prepared in powder form by grinding multivitamin tablets and then mixing, sieving, and bottling the powder. For the certification of each water-soluble vitamin, the isotope dilution mass spectrometry based on the liquid chromatography was applied. The methods for each analyte were validated by confirming the repeatability and reproducibility and by comparing with other CRMs. The property values and uncertainties for the vitamins were determined with 10 units from sample stored at − 20 °C. The homogeneity of each certified component was also examined in the range of 0.48–2.2%. All certified values for the seven water-soluble vitamins were stable for 3 or 6 years after the initial certification under storage conditions at − 20 °C. For fat-soluble vitamins, including retinol, α-tocopherol, cholecalciferol, and phylloquinone, two expert laboratories participated in analyses based on official methods, and the mean values of the reported results were assigned as reference values. The multivitamin tablet CRM (108-10-019) will be useful for validating analytical methods and for ensuring the quality of results for vitamin analysis in multivitamin tablets or similar products.

We propose that several different reactor irradiation times followed by assaying of activity for differential counting periods may be employed for quality control (QC) of neutron activation analysis (NAA) data of biological samples. It is also recommended that three to four reference materials (RMs) of similar matrix but from different agencies such as National Institute of Standards and Technology (NIST, USA), International Atomic Energy Agency (IAEA, Vienna), Institute of Nuclear Chemistry and Technology (INCT, Poland), and National Institute of Environmental Studies (NIES, Japan) including a synthetic multielemental primary standard should always be analyzed simultaneously along with the samples. Finally, the mean ± σ values so obtained may be considered as more reliable after statistical analysis. Our analytical data for Na and K in three RMs (SRM 1572, CRM H-9, and Bowen's Kale) using different irradiation periods of 15 m, 2 h, 6 h, and 1 day were comparable with the certified values within error range of + 0.2 to − 2.7%. We report our data for 20 elements in two candidate RMs corn flour (INCT-CF-3) and soya bean flour (INCT-SBF-4) from the INCT, Poland, where Z-score values for most elements are in reasonable range of certified values. [ABSTRACT FROM AUTHOR]

BACKGROUND Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have teratogenic, carcinogenic and mutagenic effects, which are priority pollutants. The formulation of pollution investigation and treatment measures depends on accurate analysis and test data, and certified reference materials (CRMs) are an important guarantee for data quality control. However, the existing relevant reference materials cannot meet the actual needs of pollution monitoring in China. OBJECTIVES To prepare four CRMs of sediments for analysis of PAHs, OCPs and PCBs, and to meet the needs of environmental monitoring and scientific research for the monitoring of priority pollutants in China. METHODS In this study, according to the specifications of certified reference materials (JJF 1006—1994, JJF1343—2012 and JJF 1646—2017), 4 CRMs of PAHs, OCPs and PCBs in different sediments (GBW07352-GBW07355) have been developed for Chinese environmental monitoring and scientific research. In the development process, in order to solve the technical difficulties of the stability of organic compound reference materials, the effects of 60Co sterilization and temperature on the stability of organic compounds were investigated. In view of the complex characteristics of the sediment sample matrix, different extraction and purification technologies were adopted to reduce or eliminate the influence of the complex matrix on the extraction solution and reduce the matrix effect of instrument measurement. Nine laboratories' collaborative analysis was carried out by using traditional methods including high performance liquid chromatography (HPLC), gas chromatography-electron capture detector (GC-ECD), gas chromatography-mass spectrometry (GC-MS) and new techniques of gas chromatography-isotope dilution mass spectrometry (GC-IDMS). RESULTS The sediment candidates have good homogeneity and stability. The certified values and expanded uncertainty for 16 PAHs, 3 OCPs and 3 PCBs are given, and the concentrations range from 9.0ng/g to 5.7μg/g, which meets the requirements of quality assurance and quality control for analysis of PAHs, OCPs and PCBs. CONCLUSIONS This series of reference materials has been approved as a national first-class reference material, numbered from GBW07352 to GBW07355. This series of CRMs can be used in analytical method validation, laboratory quality control, laboratory analysis ability assessment.

Multivitamin tablet certified reference material (CRM, 108-10-019) was developed for the analysis of seven water-soluble vitamins, including thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxine, biotin, and folic acid. The CRM was prepared in powder form by grinding multivitamin tablets and then mixing, sieving, and bottling the powder. For the certification of each water-soluble vitamin, the isotope dilution mass spectrometry based on the liquid chromatography was applied. The methods for each analyte were validated by confirming the repeatability and reproducibility and by comparing with other CRMs. The property values and uncertainties for the vitamins were determined with 10 units from sample stored at − 20 °C. The homogeneity of each certified component was also examined in the range of 0.48–2.2%. All certified values for the seven water-soluble vitamins were stable for 3 or 6 years after the initial certification under storage conditions at − 20 °C. For fat-soluble vitamins, including retinol, α-tocopherol, cholecalciferol, and phylloquinone, two expert laboratories participated in analyses based on official methods, and the mean values of the reported results were assigned as reference values. The multivitamin tablet CRM (108-10-019) will be useful for validating analytical methods and for ensuring the quality of results for vitamin analysis in multivitamin tablets or similar products. [ABSTRACT FROM AUTHOR]

As an emerging neurodegenerative disease, Alzheimer's disease (AD) has become a leading cause of dementia in older adults. Visinin-like protein-1 (VILIP-1) is an increasingly used biomarker for AD besides the widely accepted Aβ1-40, Aβ1-42, and tau. However, significant variations exist in the commercial immuno-based assays for VILIP-1 quantification, underlining the necessity to establish a traceability chain. Certified reference materials (CRMs) located at the top of the traceability chain are traceability sources for relevant matrix standard materials. In this work, VILIP-1 solution CRM with a certified value and uncertainty of 39.82±1.52 μg·g−1 was developed and certified using amino acid-based isotope dilution mass spectrometry (AA-ID-MS) and sulfur-based isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Certified values from both strategies showed great consistency, with traceability to SI units. Moreover, the candidate VILIP-1 CRM shows excellent homogeneity and can be stable for at least 7 days at −20°C and 12 months at −70°C. The VILIP-1 CRM developed can be used in value assignment to secondary calibrators and clinical matrix CRMs, showing prospects in early diagnosis and disease monitoring for AD. [ABSTRACT FROM AUTHOR]

The "purity" of an organic compound typically refers, in practice, to an assignment of the mass fraction content of the primary organic component present in the material. The "purity" value of an organic primary calibrator material is the ultimate source of metrological traceability of any quantitative measurement of the content of that compound in a given matrix. The primary calibrator may consist of a Certified Reference Material (CRM) whose purity has been assigned by the CRM producer or a laboratory may choose to value-assign a material to the extent necessary for their intended application by using appropriately valid methods. This report provides an overview of the approach, performance and applicability of the principal methods used to determine organic purity including mass balance, quantitative NMR, thermal methods and direct-assay techniques. A statistical section reviews best practice for combination of data, value assignment as the upper limit values corresponding to 100 % purity are approached and how to report and propagate the standard uncertainty associated with the assigned values. [ABSTRACT FROM AUTHOR]

A new, simple, and accurate carrier element-free coprecipitation method has been developed to separate and preconcentrate of Cd(II), Cu(II), Ni(II), and Pb(II) ions from water and food samples. The proposed method was based on utilisation of 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-thiol (BNBATT) as a new organic co-precipitant at pH 7.0 and the determination of the metal ions being examined using FAAS. To recover the metal ions analysed, The influencce of many parameters including pH, sample volume, co-precipitant quantity, and the rate and time of centrifugation, was tested. There was also monitoring the effect of matrix ions, and no interferences were found. The validity of the proposed method was verified by test of certified reference materials. The analyte ions recovery values were measured and found to be in the range of 95–100%. The relative standard deviation (RSD%) was measured to determine the precision of the proposed approach and was found to be ≤ 5.0%. The limits of detection (K = 3.0, N = 10), were determined in the range of 0.3–0.8 μg L−1. The calculated preconcentration factor was 100 for Cd(II), Cu(II) and Ni(II) and 80 for Pb(II). Satisfactory results for separation and preconcentration trace amounts of the studied metal ions in water, food, and certified reference materials samples. [ABSTRACT FROM AUTHOR]

Improved methods employed at Los Alamos National Laboratory for 231Pa/235U radiochronometry are outlined. We present elution curves obtained during 233Pa tracer preparation from 237Np. Additionally, we report model ages for uranium certified reference materials (CRMs) exhibiting a range of 235U enrichments including the first 231Pa/235U model ages for CRMs U200 and U900. Our results enable these CRMs to be used, with increased confidence, as quality control materials during nuclear forensics investigations. [ABSTRACT FROM AUTHOR]

Amounts typically used for separations prior to analysis by thermal ionization mass spectrometry for plutonium isotopic analysis at LANL are typically about 20 micrograms of plutonium. We performed a scaled-up separation experiment using 20 milligrams, in an effort to check the separation efficiency using the larger amounts. Results from this separation experiment demonstrated that Pu decay products (241Am, and 234U, 235U, 236U isotopes produced from the decay of 241Pu, 238Pu, 239Pu, and 240Pu) can be cleanly separated using the same columns we use for separation of the 20 µg quantities. The results of the scaled up separation experiments, funded through NBL as part of the DOE Office of Science project are discussed. LA-UR-22-22151. [ABSTRACT FROM AUTHOR]

The establishment of reference systems for the standardization of hemoglobin A 2 (HbA 2 ) and fetal hemoglobin (HbF), both critical for improving diagnostic accuracy in conditions such as β-thalassemia and sickle cell disease, are described. Efforts were led by the IFCC and other groups to address and reduce the variability in laboratory measurements of these hemoglobins. This document outlines the production of certified reference materials (CRMs) for HbA 2 and the development of a reference measurement procedure using isotope dilution mass spectrometry. Similarly, standardizing HbF is essential for supporting diagnostic and therapeutic strategies, particularly in managing sickle cell disease. HbF levels can predict disease outcomes and guide treatment plans. Significant challenges remain in achieving consistent measurement across laboratories, and the process for standardization for this minor hemoglobin has just begun. We are confident that the implementation of these reference systems will provide improved accuracy and traceability in the future., Competing Interests: Declaration of competing interest A. Mosca and R.P. are components of the University of Milano, carrying out researches on clinical studies, methods development and validation for diabetes and hemoglobin related disorders, sometimes sponsored by various Companies. Both have received speakers’ honoraria or consulting fees from Menarini Diagnostics, Sebia, and Tosoh Bioscience., (Copyright © 2024. Published by Elsevier B.V.)

The use of Certified Reference Materials (CRMs) is of utmost importance to achieve the comparability and traceability of data, which are essential features of measurement results in environmental and climate fields. The present paper focuses on the generation of gas mixtures at known composition of carbon dioxide at atmospheric amount-of-substance fraction in synthetic air by means of a dynamic dilution system, designed and implemented at the Istituto Nazionale di Ricerca Metrologica (INRiM). The validation of the dynamic system in terms of amount-of-substance fraction is presented. The system was also used to verify the carbon dioxide amount-of-substance fraction of a suite of gas mixtures gravimetrically prepared at INRiM in the framework of the EMPIR Joint Research Project 19ENV05 – STELLAR. Dynamic dilution proved to be an effective tool for the preparation and certification of CRMs for gaseous pollutants (i.e. carbon dioxide, nitrogen oxides) relevant for monitoring environmental pollution and climate changes.

Vinyl acetate is a restricted substance in food products. The quantification of the organic impurities in vinyl acetate is a major problem due to its activity, instability, and volatility. In this paper, while using the mass balance method to determine the purity of vinyl acetate, an improved method was established for the determination of the content of three impurities in vinyl acetate reference material, and the GC-FID peak area normalization for vinyl acetate was calibrated. The three trace organic impurities were identified by gas chromatography tandem high-resolution mass spectrometry to be methyl acetate, ethyl acetate, and vinyl propionate. The content and relative correction factors for the three organic impurities were measured. The purity of vinyl acetate determined by the mass balance method was 99.90% with an expanded uncertainty of 0.30%, and the total content of organic impurities was 0.08% with a relative correction factor of 1.23%. The vinyl acetate reference material has been approved as a national certified reference material in China as GBW (E) 062710.

Traceability and reliable results are the two pillars of analytical methods; certified reference materials (CRMs) meet this requirement. ISO 17034:2016 credentials provide brief information on general requirements for the competence of Reference Material Producers (RMPs). The different types of CRMs have been produced in recent years for chemical analysis in food, water, soil, and sediment matrices in recent years. This review provides a detailed overview of the development of CRMs in the field of marine environment, as matrix CRMs play an important role in the field of environmental monitoring. COMAR database, EVISA database: materials, LGC standards, and JRC catalogs are very helpful online resources to find various types of CRMs according to the application requirements. The classification of certified reference materials (CRMs) in the field of marine environment is presented; General information about the production and characteristics of CRMs is discussed; Examples of use of existing marine CRMs are described in detail; Importance of CRMs for QA/QC and CRMs development for chemical analysis is presented; The parameters that characterize the CRMs: representativeness, homogeneity, stability, and certified value are provided. [ABSTRACT FROM AUTHOR]

BACKGROUND From 1986 to 2007, different grades of trace gold certified reference materials (background grade, anomaly grade, medium grade and high grade) and mineral gold certified reference materials (mineralization grade, cutoff grade and concentrate grade) had been developed by IGGE and used for regional geochemical survey, mineral exploration and evaluation, mining and smelting. With the increase of the service life period and the consumption of recent years, most of the gold certified reference materials has been used up or almost used up. New gold standard materials need to be developed urgently. OBJECTIVES To develop a new gold certified reference material and compare it with the original gold certified reference material. METHODS The trace gold certified reference materials in 7 levels and mineral gold certified reference materials in 3 levels were prepared in strict accordance with relevant specifications. The collected candidates were sampled from different types of deposits and different matrices. The collected candidates were prepared through coarse crushing, drying, composite configuration, fine crushing, sieving, blending and other steps. After the particle size inspection, the cumulative content of the sample with a particle size of 0.74μm reached more than 99%, which met the requirements of the specifications. 25 bottle samples of each grade were randomly selected. Homogeneity testing was carried out by ICP-MS, FAAS and GFAAS. RESULTS The relative standard deviation (RSD) was less than 10%, and the F values of the variance test were less than the one-tailed critical value F0.05(24, 25) of 1.98, indicating that the sample uniformity was good. During the one-year investigation period, no significant changes in statistical significance were found in the fixed value components, which proved that the stability of the sample was good. Five highly experienced and skilled laboratories in geology gold samples testing in CHN were invited to evaluate the gold certified reference materials by classically reliable analytical methods. The original data conformed to the normal distribution after statistical inspection and the suspicious values were eliminated. The arithmetic mean was used as the standard value, and the uncertainty was evaluated in detail, in accordance with the latest specifications. The certified value of the copied standard material was accurate and reliable, and the uncertainty was reasonable. It was approved as a national first-level standard material in 2019. Compared with the original batch, the certified values of the two batches were basically the same, and the standard deviation of the fixed value data showed a shrinking trend, which met the requirements for copying standard materials. CONCLUSIONS This series of gold standard materials has a wide content range, and meets the value comparison and analysis monitoring of different content levels. Moreover, it has good applicability, and meets the needs of geological and mineral research, regional geochemical investigation, gold mine exploration and evaluation.

• Water content measurement requirements for plant-origin bulk materials are shown. • Development of plant-matrix CRMs by Karl Fischer titration method is needed. • Plant-matrix CRM can support a fair-trade in the grain market. • Improvement of accuracy and reliability in moisture content measurement is foreseen. • Identification of a method providing the best metrological traceability. This paper explains advantages and disadvantages of the measurement methods for moisture and water content determinations in plant-based materials, in order to identify the method providing the best metrological features. The term "moisture" is generic and it does not identify a specific measurand. In this sense, to declare proper Calibration and Measurement Capabilities (CMCs) and to develop Certified Reference Materials (CRMs), a better specification of the measurand should be given. Currently, no CMCs for moisture or water content measurements in the plant-origin bulk materials, as well as respective CRMs, are available in the Key Comparison Database (KCDB) published on the website of the Bureau International del Poids et Mesures (BIPM). Undoubtedly, those CMCs and CRMs, characterised for water content, are crucial and essential to provide metrological traceability of measurement results for the quality assessment of plant-origin bulk materials in the agricultural sector. [ABSTRACT FROM AUTHOR]

Apparent amylose content (AAC) is one of the most important parameters in rice quality evaluation. In this study, four rice reference materials used to test rice AAC were developed. The AAC of rice reference materials were measured by a spectrophotometric method with a defatting procedure, calibrated from potato amylose and waxy rice amylopectin at the absorption wavelengths of 620 and 720 nm. Homogeneity test (n = 20) was judged by F-test based on the mean squares of among and within bottles, and short- and long-term stability monitoring was performed by T-test to check if there was significant degradation at the delivery temperature of under 40 °C (14 days) and at 0–4 °C storage condition (18 months), respectively. After joint evaluation by ten laboratories, Dixion and Cochran statistical analyses were presented. The expanded uncertainties were calculated based on the uncertainty of homogeneity, short- and long-term stability, and inter-laboratory validation containing factor k = 2. It found that the four reference materials were homogenous and stable, and had the AAC (g/100 g, k = 2) of 2.96 ± 1.01, 10.68 ± 0.66, 17.18 ± 1.04, and 16.09 ± 1.29, respectively, at 620 nm, and 1.46 ± 0.49, 10.44 ± 0.56, 16.82 ± 0.75, and 24.33 ± 0.52, respectively, at 720 nm. It was indicated that 720 nm was more suitable for the determination of rice AAC with lower uncertainties. The determinations of the AAC of 11 rice varieties were carried out by two methods, the method without defatting and with calibration from the four rice reference materials and the method with a defatting procedure and calibrating from potato amylose and waxy rice amylopectin. It confirmed that the undefatted rice reference materials could achieve satisfactory results to test the rice samples with the AAC ranging from 1 to 25 g/100 g. It would greatly reduce the time cost and improve testing efficiency and applicability, and provide technical support for the high-quality development of the rice industry. [ABSTRACT FROM AUTHOR]

Natural water certified reference materials (CRMs) are mostly available in a liquid form, and they are produced starting from suitable environmental samples. Many precautions are usually needed to avoid biological or physical degradation, including filtration, acidification, and sterilization. In this study, the drawbacks associated with liquid-based seawater CRMs were tackled by developing a salt-based seawater proxy for nutrients that could be reconstituted in water solution just before use. Phosphate, silicate, and nitrate were chosen as target analytes. Sea salt mimicking the composition of seawater was spiked with an aqueous solution of the analytes and homogenized using a high-energy planetary ball mill (uhom < 1.2%). The salt powder CRM SALT-1 (https://doi.org/10.4224/crm.2022.salt-1) demonstrated good short- and long-term stability for nutrients. When the SALT-1 was reconstituted in water at the 4.0% w/w level, the resulting solution had similar properties with respect to typical seawater in terms of major constituents (± 20%), trace metals, density (1.023 g/mL), pH (8.8–9.0), and optical properties relevant to the photometric characterization. Phosphate and silicate were quantified by photometry (molybdenum blue method, batch mode), whereas nitrate was quantified by isotope dilution GC−MS (uchar < 1.2%). In the SALT-1 reconstituted seawater solution at the 4.0% w/w salt level, the nutrient amount concentration was w(phosphate, PO43−) = 1.615 ± 0.030 μmol/L, w(silicate as SiO2) = 8.89 ± 0.31 μmol/L, and w(nitrate, NO3−) = 18.98 ± 0.45 μmol/L at the 95% confidence (k = 2). Overall, the SALT-1 CRM exhibits similar nutrient profile and general analytical characteristics as the MOOS-3 CRM. However, the SALT-1 has much reduced preparation, storage, and distribution cost, likely much better long-term stability, and it could enable the production of lower cost and more accessible seawater reference materials. [ABSTRACT FROM AUTHOR]

The pure materials play a pivotal role in controlling the quality of pharmaceutical products, ensuring comparability and metrological traceability of test results, and performance evaluation of measuring instruments. Herein, the purity characterization of chronic hepatitis C virus sofosbuvir and ledipasvir pharmaceuticals was established based on the assessment of mass fractions of potential impurities in the material including heavy metals, residual solvents, and water content, as well as structurally related organic impurities. The combined estimate of these impurities by mass balance approach led to indirect purity determination of sofosbuvir and ledipasvir materials. The impurities mass fractions in each material were assigned by validated chromatographic methods, Karl Fisher titrator, and inductively coupled plasma-based method. The certified purity values of sofosbuvir and ledipasvir and their corresponding expanded uncertainties (k =2.0 at 95% CL) were found (99.79±0.03) %, (99.69±0.04) %, respectively. The developed certified reference materials (CRMs) with small uncertainty values will support pharmaceutical testing laboratories in their efforts to maintain and improve the quality of results and provide them with high-order CRMs for the accurate determination of both analytes in raw materials and finished products. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have teratogenic, carcinogenic and mutagenic effects, which are priority pollutants. The formulation of pollution investigation and treatment measures depends on accurate analysis and test data, and certified reference materials (CRMs) are an important guarantee for data quality control. However, the existing relevant reference materials cannot meet the actual needs of pollution monitoring in China. OBJECTIVES: To prepare four CRMs of sediments for analysis of PAHs, OCPs and PCBs, and to meet the needs of environmental monitoring and scientific research for the monitoring of priority pollutants in China. METHODS: In this study, according to the specifications of certified reference materials (JJF 1006-1994, JJF1343-2012 and JJF 1646-2017),4 CRMs of PAHs, OCPs and PCBs in different sediments (GBW07352 - GBW07355) have been developed for Chinese environmental monitoring and scientific research. In the development process, in order to solve the technical difficulties of the stability of organic compound reference materials, the effects of 6° Co sterilization and temperature on the stability of organic compounds were investigated. In view of the complex characteristics of the sediment sample matrix, different extraction and purification technologies were adopted to reduce or eliminate the influence of the complex matrix on the extraction solution and reduce the matrix effect of instrument measurement. Nine laboratories' collaborative analysis was carried out by using traditional methods including high performance liquid chromatography (HPLC), gas chromatography - electron capture detector (GC - ECD), gas chromatography - mass spectrometry (GC - MS) and new techniques of gas chromatography - isotope dilution mass spectrometry (GC - IDMS). RESULTS: The sediment candidates have good homogeneity and stability. The certified values and expanded uncertainty for 16 PAHs, 3 OCPs and 3 PCBs are given, and the concentrations range from 9. Ong/g to 5. 7μg/g, which meets the requirements of quality assurance and quality control for analysis of P AHs, OCPs and PCBs. CONCLUSIONS: This series of reference materials has been approved as a national first - class reference material, numbered from GBW07352 to GBW07355. This series of CRMs can be used in analytical method validation, laboratory quality control, laboratory analysis ability assessment. [ABSTRACT FROM AUTHOR]

BACKGROUND: One Rb-Sr certified reference materials (GBW04411) and one Sm-Nd certified reference materials (GBW04419) for geological age, which are potash feldspar and basalt respectively, were produced and certified about 30 years ago. They have only one certified value and their matrices differ from many other geological samples. To better assess the quality of chromatographic separation, measurement procedures and mass spectrometry performance when analyzing Rb-Sr and Sm-Nd, three CRMs which are peridotite, eclogite and granite for Rb-Sr and Sm-Nd analysis were produced, and labelled GBW04139, GBW04140 and GBW04141 respectively.OBJECTIVES: To prepare certified reference materials for analysis of Rb-Sr and Sm-Nd isotopes of different types of rocks.METHODS: Peridotite, eclogite and granite from typical areas in China were used as candidates. Referring to ‘Determinations for isotopes of lead, strontium and neodymium in rock samples (GB/T 17672-1999)’, ‘Determination of Rb-Sr isotopic geological age and Sr isotope ratio in rocks and minerals (DZ/T 0184.4-1997)’, ‘Determination of Sm-Nd isotopic geological age and Nd isotope ratio in rocks and minerals (DZ/T 0184.6-1997)’, Rb, Sr, Sm and Nd were purified by chromatographic separation, and their concentrations were analyzed by ID-TIMS, 87Sr/86Sr and 143Nd/144Nd ratios were determined by TIMS and MC-ICP-MS, respectively.RESULTS: For homogeneity testing of the three CRMs, fifteen bottles of each were randomly selected (from the 200 bottles prepared) for analysis. F-testing was used to study homogeneity. The result was insignificant (1 < F < Fcritical (vamong, vwithin), demonstrating that the three CRMs had very good homogeneity. On the basis of the homogeneity study, the minimum sample required to ensure homogeneity was 1g for Peridotite, and 0.3g for Eclogite and Granite. The long-term stability of the samples was evaluated five times over 26 months. A linear model was used as a basic model for evaluating stability of Rb, Sr, Sm, Nd concentration and 87Sr/86Sr, 143Nd/144Nd. Given that|b1|

The relevance of the study is caused by significant interest of scientists working in the field of coal geology and specialists of chemical and analytical laboratories practicing quantitative elemental analysis of environmental objects, to the problem of high-precision determination of low concentrations of chemical elements in coals and coal materials for the subsequent use of the obtained data in solving scientific and various technological tasks. The main aim is to consider and generalize the most frequently used methodological approaches to the determination of chemical elements in a wide range of their contents in coals (coal materials), as well as to assess the precision and accuracy of the ICP-MS method results obtained after open acid decomposition of samples and their fusion with lithium metaborate, comparing data with the INAA results method and statistical data processing. Objects: coals, carbonaceous siltstones and coalified timber from the Spetsugli germanium deposit, located on the southwestern edge of the Khanka massif in the eastern part of the Pavlovskoe coal-bearing depression, Primorsky Krai. Methods: inductively coupled plasma mass spectrometry (ICP-MS), applied after transferring the studied samples to a dissolved form, and a non-destructive quantitative method of instrumental neutron activation analysis (INAA). Methods of mathematical statistics were used to process the obtained results. Results. The results of ICP-MS analysis of three certified reference materials (CRM) of fly ash from KATEK GSO 9237-2008 (ZUK-2), brown coal ash from the Azeiskoe coal deposit GSO 7177-95 (ZUA-1) and bituminous CLB-1 coal of the US Geological Survey were obtained, presented in the form of data on their trace element composition in comparison with the certified and recommended values. The results of the determination of some elements given in the paper supplement the data on these CRMs presented in the certificate. Comparison of ICP-MS analysis results for samples of coals and carbonaceous rocks after different methods of chemical sample preparation: technique of open acid digestion and fusion with lithium metaborate, was carried out. The behavior of individual elements during these processes has been studied. Matching the obtained data by ICP-MS and INAA methods is performed. All results were processed metrologically and their permissible discrepancy was shown.

Introduction: The metabolomics quality assurance and quality control consortium (mQACC) is enabling the identification, development, prioritization, and promotion of suitable reference materials (RMs) to be used in quality assurance (QA) and quality control (QC) for untargeted metabolomics research. Objectives: This review aims to highlight current RMs, and methodologies used within untargeted metabolomics and lipidomics communities to ensure standardization of results obtained from data analysis, interpretation and cross-study, and cross-laboratory comparisons. The essence of the aims is also applicable to other 'omics areas that generate high dimensional data. Results: The potential for game-changing biochemical discoveries through mass spectrometry-based (MS) untargeted metabolomics and lipidomics are predicated on the evolution of more confident qualitative (and eventually quantitative) results from research laboratories. RMs are thus critical QC tools to be able to assure standardization, comparability, repeatability and reproducibility for untargeted data analysis, interpretation, to compare data within and across studies and across multiple laboratories. Standard operating procedures (SOPs) that promote, describe and exemplify the use of RMs will also improve QC for the metabolomics and lipidomics communities. Conclusions: The application of RMs described in this review may significantly improve data quality to support metabolomics and lipidomics research. The continued development and deployment of new RMs, together with interlaboratory studies and educational outreach and training, will further promote sound QA practices in the community. [ABSTRACT FROM AUTHOR]

In this study, data from thirteen laboratories from around the world are presented for a successful certification of uranium isotope ratios in uranium ore concentrate (UOC) certified reference materials from the National Research Council Canada. Different mass spectrometric measurement principles (including SF‐ICP‐MS, quadruple ICP‐MS, TIMS, MC‐ICP‐MS, SIMS and AMS) and measurement procedures were employed. In general, data from all sources exhibit good consistency with TIMS and MC‐ICP‐MS showing superior performance. The three candidate UOC CRMs (UCLO‐1, UCHI‐1 and UPER‐1) have natural uranium isotope ratios with certified values of 0.5304(7) × 10−4, 0.5475(2) × 10−4 and 0.5361(4) × 10−4 for n(234U)/n(238U) and 0.007 2563(13), 0.007 2563(10) and 0.007 2542(11) for n(235U)/n(238U), respectively, with expanded uncertainty (k = 2) applicable to the last digit of the value given in the parentheses. Information values for n(236U)/n(238U) in these three CRMs, measured by AMS, are also provided: 10 × 10−12, 200 × 10−12 and 22 × 10−12. The uncertainties of the proposed certified values of uranium isotope ratios in UOC CRMs are superior to available reference materials, and the values of n(234U)/n(238U) and n(236U)/n(238U) show significant variation among the three CRMs. [ABSTRACT FROM AUTHOR]

Through high fidelity measurements of four different plutonium certified reference material standards from New Brunswick Laboratory, the mass fractionation correction factor for the 240Pu/239Pu major isotope ratio measurements by the total evaporation methodology using thermal ionization mass spectrometer instruments is shown to depend on the elapsed time since separation of the decay products from the analyzed plutonium fraction. Systematic biases arising from this matrix dependence of the mass fractionation correction factor are larger than the precision obtained in routine TE measurements of the 240Pu/239Pu major isotope ratio using thermal ionization mass spectrometry regarded as the gold standard for these measurements. LA-UR-21–21,941. [ABSTRACT FROM AUTHOR]

Silicon (Si) is the second most abundant element in the continental crust. Studies have illustrated that silicon isotopes have a potential to be tracers in the biogeochemical silica cycle. This paper details a developed method for the production and certification of a new Si reference material with natural‐like isotopic composition using a fully calibrated multi‐collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS). To correct for the mass bias effect, three blend solutions were gravimetrically prepared with isotopically enriched 28Si, 29Si and 30Si materials. Homogeneity and stability tests were performed, and no significant influences were found. Uncertainties of property values were evaluated, and the traceability to the International System of Units (SI) was established. The developed certified reference material (GBW04503) is a silicon powder (≈ 300 mesh) with high purity (≈ 0.999 99 kg kg−1), which can be used in silicon isotopic measurement to support validation of analytical procedures and/or quality control of gas source mass spectrometry (GS‐MS) or MC‐ICP‐MS. The certified isotope amount ratios of n(29Si)/n(28Si) and n(30Si)/n(28Si) are 0.050291(12) mol mol−1 and 0.033397(16) mol mol−1, respectively, (k = 2), and the certified isotope amount fractions of silicon are 92.2776(20)% (28Si), 4.6407(10) % (29Si) and 3.0818(14)% (30Si) (k = 2). Meanwhile, the delta value of δ30/28SiNBS 28 = 1.679(17)‰ was obtained (k = 2). [ABSTRACT FROM AUTHOR]

Many countries are currently focused on expanding the range of national means for measurement unit transfer characterized by established metrological traceability within international organizations. As well as demonstrating the high level of measurement capabilities provided by organizations and countries, such activities facilitate a solution to the global problem of ensuring the comparability of measurement results obtained for different objects at various times in diverse parts of the world. The present article highlights issues involved in establishing the metrological traceability of physicochemical measurement results. Curent international practice in establishing traceability of reference material certified values is described. In addition, the authors provide a brief overview of internationally recognized concepts related to the metrological traceability of reference materials. [ABSTRACT FROM AUTHOR]

The article describes an approach to establishing the metrological traceability of reference materials adopted by TC 1.12 Reference Materials of the Euro-Asian Cooperation of National Metrological Institutions (COOMET). Specific examples of the production of COOMET reference materials are given. Approaches to demonstrating metrological traceability of reference materials depending on the method of their characterization are considered, i.e., the application of state measurement standards, interlaboratory experiments, as well as primary reference measurement procedures for characterizing reference materials when no state standards for measurement units are available. [ABSTRACT FROM AUTHOR]