Metrological tools for quality control in distilled beverages with a focus on the development of reference materials and proficiency tests

Ensuring metrological traceability and result validity is a critical aspect of testing laboratories to obtain reliable results and ensure comparability. A survey was conducted in testing laboratories to assess the extent of traceability and result validity assurance through the utilization of certified reference materials and the implementation of quality assurance. The objective of this survey is to determine the necessary types of reference materials and proficiency tests, particularly for air and exhaust gas laboratories, in order to enhance the development of reference materials and proficiency testing services. The survey involved distributing a questionnaire regarding the utilization of certified reference materials and the implementation of quality assurance to accredited air and exhaust gas testing laboratories. The findings revealed that out of the 25 participating laboratories, a significant portion had not yet incorporated the use of certified reference materials in their testing processes. Although internal quality control measures were generally implemented across laboratories, only 40% had adopted external quality control methods, such as comparative and proficiency tests. Consequently, it is evident that there is an urgent need to develop reference materials for all parameters of air and exhaust gas testing, and there is a requirement for updated information for proficiency test providers.

WFSR report 2021.014 | 9 Summary National Reference Laboratories (NRLs) are part of the system responsible for the control and enforcement of EU food and feed law. Wageningen Food Safety Research (WFSR) has been designated as the NRL for thirteen subjects. The tasks of a NRL depend on its research fields. This report gives an overview of the activities performed by all of NRLs of WFSR in 2020. These NRLs are for: milk and milk products, marine biotoxins, animal proteins, certain substances and residues thereof as laid down in Directive 96/23/EC, additives for use in animal nutrition (feed additives), genetically modified organisms (GMOs) in food and feed, pesticides, metals and nitrogenous substances in feed and food, mycotoxins and plant toxins in food and feed, processing contaminants, halogenated persistent organic pollutants in food and feed, food borne viruses and water content of poultry. This report first gives an overview of relevant legislation and information on the networks of EURLs, NRLs and OLs. For every NRL, a description is then given of all activities performed in the EURL-NRL network such as participation in EURL-NRL workshops, working groups, and proficiency and comparative tests. This is followed by a description of the assistance given to OLs in the form of quality control and/or advice. Finally, the scientific and technical support given to the competent authority is discussed. In some cases, the contact with other NRLs is discussed. An important NRL task is to stay up to date with current developments within its NRL domain. Every EURL organises one or two meetings (workshops) every year for that purpose. Participation in these EURL-NRL workshops is mandatory. In 2020, due to COVID-19, most of these workshops were online. All workshops have been attended by NRLs of WFSR. Additionally, the NRLs have actively participated in EURL working groups, to improve analytical methods. To test the analytical capabilities of NRLs, the EURLs organise proficiency tests. Due to EURL proficiency tests sometimes being limited in their scope, the NRLs have also participated in proficiency tests organised by other organizations if thought to be relevant. Most results (z-scores) in these proficiency tests were good; only a few ‘questionable’ and a few ‘unsatisfactorily’ result were reported. Follow-up actions were implemented in those cases. The performance of the OLs has been assured by checking the results of their performance in proficiency tests (organised by other laboratories or the NRL) or by sending assurance-samples. Some OLs have also received technical support with regard to their analyses.

Development and application of proficiency testing (PT) to evaluate the diagnostic capacity of SARS-CoV-2 by RT-qPCR - A practical and metrological approach

Immunochemical methods (in particular immunoassays) have been applied to spring and surface water samples, respectively, which were set-up as reference materials (RM) within two proficiency testing campaigns. For the first set of proficiency tests (PTs) described here (which were actually the second round of PTs organized, spring 2005), three ELISAs (enzyme-linked immunosorbent assays) were employed in the enzyme tracer format for isoproturon, diuron, and atrazine, respectively. Results were evaluated in comparison with conventional reference methods (LC, GC). Based on their Z-score laboratory performances, the results for isoproturon and diuron were satisfactory, both for fortified spring water and for the blind solution. The results for atrazine were strongly influenced by other triazines present and needed detailed interpretation. For the second set of PTs described here (which were actually the third round of PTs organized, spring 2006), two ELISAs in the coating antigen format were used for isoproturon and diuron, and the result was included with the results obtained by conventional methods during the PTs. The results (the Z-scores) for isoproturon were again classified as satisfactory, in both fortified surface water and blind solution. The results for diuron in ELISA showed an influence of the water matrix, while the analysis of the blind solution was satisfactory. In addition, an ELISA in the enzyme tracer format was applied to analyze isoproturon, diuron, and atrazine in surface water samples, which had been set-up and spiked during a field trial (tank experiment) at the Maas River at Eijsden, The Netherlands. The immunoassay results were compared with those from an in-house on-line SPE LC/MS-MS used as reference. Although the immunochemical results were sometimes higher than those determined in the reference analysis, the general concentration trends in the samples were similar. The contribution of immunochemical methods to the implementation of the European Water Framework Directive is also discussed.

Proficiency testing (PT) plays a vital role in the plywood manufacturing industry, acting as a quality assurance tool to maintain high standards in product consistency and reliability. This study evaluates the effectiveness of PT in identifying and addressing quality issues within plywood production, focusing on three main objectives: assessing PT’s role in uncovering quality problems, analyzing root causes, and proposing targeted solutions for process improvement. The research involved eight laboratories evaluating the Modulus of Rupture (MoR) and Modulus of Elasticity (MoE) of plywood samples, with results statistically analyzed to measure inter-laboratory consistency and identify performance gaps. To ensure reliable testing, the PT samples were prepared in line with IS 303:1989 standards, emphasizing homogeneity and stability. Statistical analyses revealed variability among laboratories, highlighting areas for improvement in material handling and testing protocols. The study found that PT is instrumental for the industry, not only in identifying discrepancies but also in fostering a culture of continuous quality enhancement. Recommendations for improvement include refining the adhesive application, optimizing pressing parameters, ensuring accurate layer alignment, and implementing thorough end-of-line inspections. Quality control measures such as random sampling, supplier audits, and traceability systems are also recommended to maintain consistency. The study advocates for comprehensive employee training and cross-functional collaboration across production, quality assurance, and R&D teams to enhance overall product quality. By addressing critical process variables and leveraging PT as a benchmarking tool, plywood manufacturers can meet regulatory standards and customer expectations. This research underscores the importance of PT in delivering actionable insights for improving product quality and reliability, ultimately supporting the industry’s growth and commitment to safe, high-quality plywood products.

The 2010 CCQM-K79 'Comparison of value-assigned CRMs and PT materials: Ethanol in aqueous media' is the second key comparison directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs). CCQM-K79 compared the assigned ethanol values of proficiency test (PT) and certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Nine NMIs submitted 27 CRM or value-assigned PT materials for evaluation. These materials represent many of the higher-order reference materials then available for this commercially and forensically important measurand.The assigned ethanol mass fraction in the materials ranged from 0.1 mg/kg to 334 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analytical team using a gas chromatography with flame ionization detection (GC-FID) method of demonstrated trueness and precision.Given the number of materials and the time required for each analysis, the majority of the measurements were made in two measurement campaigns ('runs'). Due to a shipping delay from one NMI, an unanticipated third campaign was required. In all three campaigns, replicate analyses (three injections of one preparation separated in time) were made for one randomly selected unit of each of the 27 materials. Nine of the 27 materials were gravimetrically diluted before measurement to provide solutions with ethanol mass fraction in the established linear range of the GC-FID method. The repeatability measurement value for each analyzed solution was estimated as the mean of all replicate values. The within- and between-campaign variance components were estimated using one-way ANOVA. Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals for the mean values.Uncertainty-weighted generalized distance regression was used to establish the key comparison reference function (KCRF) relating the assigned values to the repeatability measurements. On the basis of leave-one-out cross-validation, all of the assigned values for all 27 materials were deemed equivalent at the 95% level of confidence. These materials were used to define the KCRF.Parametric bootstrap Monte Carlo was used to estimate 95% level-of-confidence coverage intervals for the degrees of equivalence of materials, d ± U95(d), and of the participating NMIs, D ± U95(D). Because of the very wide range of ethanol mass fraction in the materials, these degrees of equivalence are expressed in percent relative form: %d ± U95(%d) and %D ± U95(%D). The median of the absolute values of the %D for the participating NMIs is less than 0.05% with a median U95(%D) of less than 1%. These results demonstrate that the participating NMIs have the ability to correctly value-assign CRMs and proficiency test materials for ethanol in aqueous media and similar measurands.Main text.To 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).

The validation of diagnostic methods (and the subsequent results generated by a laboratory) are improved through participation in inter-laboratory comparisons (IC), such as proficiency-testing (PT) programmes and other exercises referred to as 'ring tests' or 'ring trials' (RTs). This is a requirement to comply with international quality standards. Validating a method is a continuous process and taking part in ongoing PT programmes supports the management of a method's life cycle, providing continuing assessment of fitness (sometimes referred to as the 'validation retention status'). Proficiency-testing panel designs ensure that the methods used, particularly diagnostic specificity and sensitivity, are suitably challenged. Appraising PT results over time can illustrate whether the laboratory's performance is stable, improving or worsening, and proficiency tests can also highlight variations in the performance of assays. The development of new proficiency tests can support the implementation of novel diagnostics technologies, such as whole genome sequencing and point-of-care testing, and assist in cross-sectoral partnerships focusing on One Health approaches, which are high on the agenda for infectious disease control. For example, the rapid design and distribution of emergency exempted assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) means that these assays were not as rigorously evaluated as assays for established infectious diseases. Therefore, participation in PT programmes for SARS-CoV-2 is essential to understand the performance of these assays. While other mechanisms help to underpin laboratory activities, PT has been, and should remain, an integral part of laboratory quality assurance. Resources must be directed towards increasing and improving the quality of PT (for example, availability and accessibility of suitable biological and reference materials are essential for a PT provider to execute its duties), to support established and novel methods such as genomic and point-of-care tests.

This article deals with the performance of testing laboratories in proficiency testing (EP) conducted by the Network Metrológica of Rio Grande do Sul (RMRS). The EP are used by laboratories, clients, accreditation bodies and regulatory authorities as a tool for control and verification of the technical capacity of the laboratory. The RMRS, non-profit technical association, has been promoting since 1997 the implementation of programs for the testing of proficiency (PEP). In 2007, fourteen EP will be promoted by RMRS. Among them, destaca PEP in microbiological analysis of natural waters, which is the only one in Brazil, which has the scope to microbiological analysis of natural waters. This article presents the trend of the results obtained by the laboratories participating in the PEP’s RMRS of microbiological analysis in natural waters over the years. Keywords: tests of proficiency (EP), performance, testing laboratories, microbiological analysis of natural waters.

Hemoglobin A1C (HbA1C) is used to evaluate glycemic control over a three-month period. Blood matrix-based HbA1C materials are needed for quality control and evaluation of HbA1C measurements. This study investigated the commutability of blood materials (BMs) and aimed to upgrade BMs for HbA1C testing for use as proficiency test (PT) material. We measured BMs from a DM blood donor (n = 1), an in vitro glycation procedure (n = 3), and from commercial sources (n = 2) for HbA1C in parallel with fresh unprocessed BMs (n = 3) and clinical blood samples (n = 25). Two NGSP-certified methods, including a turbidimetric and an enzymatic immunoassay, were used for HbA1C determinations. Commutability as investigated according to CLSI EP14-Ed4 guidelines. The commutable BMs exhibited a mean paired difference of 0% to 9% when compared to reference methods, whereas the non-commutable BMs represented a mean paired difference of 3% to 11%. Fresh, unprocessed BMs with a low HbA1C of 6.0% were more commutable than BMs with a high HbA1C. The values of HbA1C in BMs (mean and uncertainty following ISO Guide 35 for RM production) were applied to upgrade the PT material to be used as a reference material. The relative uncertainty of BM-Ndm-1 and BM-Gcb-3 were 1 and 0.4%, respectively. The commutability of hemoglobin in BMs is dependent on the preparation process. Blood materials with a high HbA1C content are usually less commutable versus materials with low HbA1C content when prepared by the same process. Our study showed BMs can be successfully used as quality control or PT materials.

Quantification of phosphatidylethanol combining dried blood spots sampling with Orbitrap-based LC-HRMS platform: Method validation and proficiency testing

Comprehensive assessment of antimalarial drug resistance should include measurements of antimalarial blood or plasma concentrations in clinical trials and in individual assessments of treatment failure so that true resistance can be differentiated from inadequate drug exposure. Pharmacometric modeling is necessary to assess pharmacokinetic-pharmacodynamic relationships in different populations to optimize dosing. To accomplish both effectively and to allow comparison of data from different laboratories, it is essential that drug concentration measurement is accurate. Proficiency testing (PT) of laboratory procedures is necessary for verification of assay results. Within the Worldwide Antimalarial Resistance Network (WWARN), the goal of the quality assurance/quality control (QA/QC) program is to facilitate and sustain high-quality antimalarial assays. The QA/QC program consists of an international PT program for pharmacology laboratories and a reference material (RM) program for the provision of antimalarial drug standards, metabolites, and internal standards for laboratory use. The RM program currently distributes accurately weighed quantities of antimalarial drug standards, metabolites, and internal standards to 44 pharmacology, in vitro, and drug quality testing laboratories. The pharmacology PT program has sent samples to eight laboratories in four rounds of testing. WWARN technical experts have provided advice for correcting identified problems to improve performance of subsequent analysis and ultimately improved the quality of data. Many participants have demonstrated substantial improvements over subsequent rounds of PT. The WWARN QA/QC program has improved the quality and value of antimalarial drug measurement in laboratories globally. It is a model that has potential to be applied to strengthening laboratories more widely and improving the therapeutics of other infectious diseases.

The participation in proficiency testing (PT) is essential for testing laboratories to prove their technical competence. The aim of this study was to produce a quantitative reference material (RM) for PT containing Bacillus cereus in milk powder. A sterile solution of 10% skim milk containing 100 mM sucrose was contaminated with a B. cereus strain in a specific concentration. The homogenized matrix was distributed into vials and freeze-drying. The batch produced was considered sufficiently homogeneous assigning a target standard deviation of 0.25. The RM was stable at ≤ -70 ºC and (-20 ± 4) ºC for 1,058 and 60 days, respectively. In the evaluation of temperatures for the transport of material, the RM was stable at 4, 25 and 35 ºC during four days. It is concluded that the batch produced had all the necessary requirements to be used as items of PT.

This study explores whether a Truku Seediq kindergarten immersion program in Taiwan has contributed to stemming indigenous language erosion. The preliminary results suggest areas for improvement in the ongoing project, and may serve as a starting point for future preschool indigenous language immersion programs. The project centers on five activities: (1) weekly culture-based language classes, (2) bimonthly teachers’ empowerment workshops, (3) online documentation of teaching processes and activities, (4) advisory visits and evaluations, and (5) development of pedagogical materials. Data were collected through focus group interviews, observations, advisory visits, and proficiency tests. The results show both that the immersion program improves the children’s proficiency and that it faces obstacles: lack of qualified teachers proficient in the language and culture-based teaching, insufficient hours of immersion and co-teaching with elders, imperfect communication in the administrative system, obstacles to collaboration with families and communities, and lack of effective pedagogical materials and proficiency tests.

Asia-Pacific Metrology Program (APMP) and Asia-Pacific Laboratory Accreditation Cooperation (APLAC) joint proficiency testing with metrological reference values for hazardous elements in cabbage

Proficiency test in Japan for the elements in tea-leaf powder