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The physicochemical properties of petroleum products in commercial transactions are crucial for quality control in the oil and gas industry. However, different laboratories often produce slightly different measurement results. These variations can be significant when approving or rejecting properties based on regulatory agency and environmental body specifications. A simple arithmetic average is typically used to determine the most probable value in disputes. This study proposed using a Data Reconciliation approach to address the disparity between the projected model and empirical data. An objective function was employed to optimize and evaluate parameters using maximum likelihood estimation, considering the experimental uncertainty values. This study found that the flash point of jet fuel, as determined by the Tag Closed Cup Tester, was within the specified range (maximum of 40 °C). The application of this tool resolved a dispute between a supplier and a customer, as the reconciled value with minimized uncertainty was determined to be 37.5 ± 2.0 °C. Additionally, the study utilized experimental results from 12 accredited laboratories to determine a single reconciled value for the final boiling point of gasoline. Despite the varying experimental uncertainties ranging from 6.0 °C to 13 °C, the reconciled uncertainty was minimized to 2.6 °C. The last case study identified that ASTM D4294 was incompatible with other test methods for evaluating the mass fraction in diesel oil. In this manner, Data Reconciliation enhanced the accuracy and effectively reduced measurement uncertainties, rendering it a potent tool for resolving legal disputes when evaluating the compliance of the physicochemical properties of petroleum products in commercial transactions. [ABSTRACT FROM AUTHOR]

Mycotoxins are toxic molecules produced by multiple fungal species, including Aspergillus and Fusarium. Fungal infection of crops can result in mycotoxins entering the animal and human food supply. Enzyme-linked immunosorbent assays and other immunological assays have been developed to detect mycotoxins in foods. To calibrate the response of those methods, reference materials with known amounts of homogeneously dispersed mycotoxins are often utilized, where the mycotoxin concentrations have been determined using high-performance liquid chromatography coupled with absorbance or fluorescence detection methods, or high-performance liquid chromatography coupled with mass spectrometry detection methods. Therefore, it is important that the analytical methods provide accurate and precise quantitation of mycotoxins. The reference materials must also contain homogeneously dispersed known quantities of mycotoxin. To evaluate the accuracy and precision of mycotoxin reference materials and the analytical methods, quantitative results from multiple laboratories were completed each year for several years on ground corn check samples containing known levels of mycotoxins. Results for the quantitation of aflatoxin-containing corn reference samples are presented in this article. [ABSTRACT FROM AUTHOR]

The inclusion of quantitative nuclear magnetic resonance (qNMR) spectroscopy in industry has historically been stifled by a lack of accessibility, caused in‐part by the large costs of traditional high‐field spectrometers, the maintenance required for these, and the expertise necessary to manage and use them. In recent years, the emergence of benchtop NMR technology, an accessible, affordable, and automatable alternative, has led to a more feasible incorporation of NMR into quality control spaces, an area traditionally reserved for other techniques such as gas chromatography and liquid chromatography, which are routinely combined with detection techniques such as mass spectrometry. While these techniques are commonly used in analyzer‐type applications using gold standard methods of analysis, wherein an instrument is dedicated to performing specific assays, this remains uncommon for NMR. Herein, we perform a full method verification using benchtop qNMR on a population of benchtop NMR instruments according to the ASTM designation E691–22, a standard used to determine the precision of a test method. To our knowledge, this is the first published example of this type of study for benchtop NMR spectroscopy. For this work, a total of five analysts performed assays on 23 different benchtop NMR instruments for the analysis of hydroxypropyl betadex according to the USP–NF method, and the results are compared using a variety of statistical methods. The results of this work demonstrate that benchtop NMR technology is effective and robust under repeatability and reproducibility conditions and is a powerful tool for these types of routine quality control analyses. [ABSTRACT FROM AUTHOR]

The physicochemical properties of petroleum products in commercial transactions are crucial for quality control in the oil and gas industry. However, different laboratories often produce slightly different measurement results. These variations can be significant when approving or rejecting properties based on regulatory agency and environmental body specifications. A simple arithmetic average is typically used to determine the most probable value in disputes. This study proposed using a Data Reconciliation approach to address the disparity between the projected model and empirical data. An objective function was employed to optimize and evaluate parameters using maximum likelihood estimation, considering the experimental uncertainty values. This study found that the flash point of jet fuel, as determined by the Tag Closed Cup Tester, was within the specified range (maximum of 40 °C). The application of this tool resolved a dispute between a supplier and a customer, as the reconciled value with minimized uncertainty was determined to be 37.5 ± 2.0 °C. Additionally, the study utilized experimental results from 12 accredited laboratories to determine a single reconciled value for the final boiling point of gasoline. Despite the varying experimental uncertainties ranging from 6.0 °C to 13 °C, the reconciled uncertainty was minimized to 2.6 °C. The last case study identified that ASTM D4294 was incompatible with other test methods for evaluating the mass fraction in diesel oil. In this manner, Data Reconciliation enhanced the accuracy and effectively reduced measurement uncertainties, rendering it a potent tool for resolving legal disputes when evaluating the compliance of the physicochemical properties of petroleum products in commercial transactions.

Recombinant human erythropoietin (EPO) is a biopharmaceutical frequently used in the treatment of anemia. It is a heavily glycosylated protein with a diverse and complex glycome. EPO N-glycosylation influences important pharmacological parameters, prominently serum half-life. Therefore, EPO N-glycosylation analysis is of the utmost importance in terms of controlling critical quality attributes. In this work, we performed an interlaboratory study of glycoanalytical techniques for profiling and in-depth characterization, namely (1) hydrophilic interaction liquid chromatography with fluorescence detection after 2-aminobenzamide labeling (HILIC-FLD(2AB)) and optional weak anion exchange chromatography (WAX) fractionation and exoglycosidase digestion, (2) HILIC-FLD after procainamide labeling (PROC) optionally coupled to electrospray ionization-MS and (3) matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS). All techniques showed good precision and were able to differentiate the unique N-glycosylation profiles of the various EPO preparations. HILIC-FLD showed higher precision, while MALDI-TOF-MS covered the most analytes. However, HILIC-FLD differentiated isomeric N-glycans, i.e., N-acetyllactosamine repeats and O-acetylation regioisomers. For routine profiling, HILIC-FLD methods are more accessible and cover isomerism in major structures, while MALDI-MS covers more minor analytes with an attractively high throughput. For in-depth characterization, MALDI-MS and HILIC-FLD(2AB)/WAX give a similar amount of orthogonal information. HILIC-FLD(PROC)-MS is attractive for covering isomerism of major structures with a significantly less extensive workflow compared to HILIC-FLD(2AB)/WAX. [ABSTRACT FROM AUTHOR]

The widespread use of liquid fuels can be monitored by their density and light fractions, which affect storage, combustion, handling, and contractual issues. The quantitative measurement of fuel density is carried out using an analytical procedure whose test method presents precision data (repeatability and reproducibility) at 15 °C, whereas Brazilian commercial legislation uses a base temperature of 20 °C. Therefore, the scope of this study was to evaluate whether there are statistically significant differences between these two temperatures. An interlaboratory study, considering homogeneity and stability checks, was carried out, and the data were treated using a one-way analysis of variance in a single-stage nested design for calculating the density precision data (under repeatability and reproducibility conditions). After using an F test to compare the variances at 15 °C and 20 °C, one concluded that these precision data are not always metrologically comparable. [ABSTRACT FROM AUTHOR]

A call for data on the occurrence of alkylfurans in food and feed from EFSA triggered the development of new methods to cover next to furan also 2- and 3-methylfuran, 2,5-dimethyl- and 2-ethylfuran as well as 2-pentylfuran. A significant variability was noticed when comparing analysis of 2-pentylfuran and furans in the same matrix performed by different laboratories. To assess the variability an interlaboratory study including eight laboratories was organised. The highest variabilities were observed when analysing cereals, with measurements of 2-pentylfuran indicating concentrations from 8 mg/kg up to more than 1000 mg/kg in the same sample. This study illustrates that the analysis of 2-pentylfuran requires special attention, and that additional method development would be necessary to ensure reliable and reproducible determination of 2-pentylfuran at contamination level. Moreover, a recent evaluation of the EFSA Panel on Food Additives and Flavourings indicates that concerns for genotoxicity, reason why it was grouped with the shorter alkylfurans, are now ruled out. We question the need and justification to include 2-pentylfuran in the analytical method as requested by EFSA, from both the analytical and the safety perspective. [ABSTRACT FROM AUTHOR]

Embryonic zebrafish represent a useful test system to screen substances for their ability to perturb development. The exposure scenarios, endpoints captured, and data analysis vary among the laboratories who conduct screening. A lack of harmonization impedes the comparison of the substance potency and toxicity outcomes across laboratories and may hinder the broader adoption of this model for regulatory use. The Systematic Evaluation of the Application of Zebrafish in Toxicology (SEAZIT) initiative was developed to investigate the sources of variability in toxicity testing. This initiative involved an interlaboratory study to determine whether experimental parameters altered the developmental toxicity of a set of 42 substances (3 tested in duplicate) in three diverse laboratories. An initial dose-range-finding study using in-house protocols was followed by a definitive study using four experimental conditions: chorion-on and chorion-off using both static and static renewal exposures. We observed reasonable agreement across the three laboratories as 33 of 42 test substances (78.6%) had the same activity call. However, the differences in potency seen using variable in-house protocols emphasizes the importance of harmonization of the exposure variables under evaluation in the second phase of this study. The outcome of the Def will facilitate future practical discussions on harmonization within the zebrafish research community. [ABSTRACT FROM AUTHOR]

For successful elucidation of a food-borne infection chain, the availability of highquality sequencing data from suspected microbial contaminants is a prerequisite. Commonly, those investigations are a joint effort undertaken by different laboratories and institutes. To analyze the extent of variability introduced by differing wet-lab procedures on the quality of the sequence data we conducted an interlaboratory study, involving four bacterial pathogens, which account for the majority of food-related bacterial infections: Campylobacter spp., Shiga toxin-producing Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The participants, ranging from German federal research institutes, federal state laboratories to universities and companies, were asked to follow their routine in-house protocols for short-read sequencing of 10 cultures and one isolated bacterial DNA per species. Sequence and assembly quality were then analyzed centrally. Variations within isolate samples were detected with SNP and cgMLST calling. Overall, we found that the quality of Illumina raw sequence data was high with little overall variability, with one exception, attributed to a specific library preparation kit. The variability of Ion Torrent data was higher, independent of the investigated species. For cgMLST and SNP analysis results, we found that technological sequencing artefacts could be reduced by the use of filters, and that SNP analysis was more suited than cgMLST to compare data of different contributors. Regarding the four species, a minority of Campylobacter isolate data showed the in comparison highest divergence with regard to sequence type and cgMLST analysis. We additionally compared the assembler SPAdes and SKESA for their performance on the Illumina data sets of the different species and library preparation methods and found overall similar assembly quality metrics and cgMLST statistics. [ABSTRACT FROM AUTHOR]

Mycotoxins are toxic molecules produced by multiple fungal species, including Aspergillus and Fusarium. Fungal infection of crops can result in mycotoxins entering the animal and human food supply. Enzyme-linked immunosorbent assays and other immunological assays have been developed to detect mycotoxins in foods. To calibrate the response of those methods, reference materials with known amounts of homogeneously dispersed mycotoxins are often utilized, where the mycotoxin concentrations have been determined using high-performance liquid chromatography coupled with absorbance or fluorescence detection methods, or high-performance liquid chromatography coupled with mass spectrometry detection methods. Therefore, it is important that the analytical methods provide accurate and precise quantitation of mycotoxins. The reference materials must also contain homogeneously dispersed known quantities of mycotoxin. To evaluate the accuracy and precision of mycotoxin reference materials and the analytical methods, quantitative results from multiple laboratories were completed each year for several years on ground corn check samples containing known levels of mycotoxins. Results for the quantitation of aflatoxin-containing corn reference samples are presented in this article.

A new quality control (QC) test sample for gas chromatography–mass spectrometry (GC–MS) was created and analysed to test the comparability and repeatability of chemical forensics results within the Organisation for the Prohibition of Chemical Weapons (OPCW)–designated laboratories. The QC test sample was designed in collaboration between four laboratories and consists of 27 compounds which evaluate the performance of GC–MS instruments. This solution was analysed with GC–MS(EI) in 11 laboratories, seven of which were OPCW designated. The participating laboratories analysed the sample multiple times on consecutive days, as well as after the analysis of a set of complex matrix samples. Retention times, retention indices, peak areas, peak tailing values, signal-to-noise ratios, and isotope ratios were extracted from the GC–MS data, and statistical multivariate analyses with principal component analysis and Hotelling's T2-tests were conducted. The results from these analyses indicate that differences between GC–MS analyses by multiple laboratories were not statistically significant at the 5% level, as the approximate p-value for the null hypothesis of “no differences between the runs” was 0.69. However, similar data processing methods and data normalisation are essential for enabling the reliable comparison of chemical fingerprints between laboratories. A composition for the QC sample and criteria for acceptable GC–MS performance for chemical forensics are proposed. The composition and criteria differ from the currently used chemical weapons verification analysis QC sample by e.g. broadening the range for retention index calculations by addition of new alkane compounds, including new chemicals with concentrations close to the limit of detection (10–100 ng/ml), and including compounds with higher polarity to emulate real-life forensic samples. The proposed criteria include monitoring of retention indices, isotope ratios, peak tailing, signal-to-noise ratios, peak height, mass spectra, and sensitivity of the instrument. The new compounds and criteria will be the subject of future confidence building exercises to validate their relevancy on a large scale.

Synthetic opioids such as fentanyl account for over 71,000 of the approximately 107,000 overdose deaths reported in the United States in 2021. Fentanyl remains the fourth most identified drug by state and local forensic laboratories, and the second most identified drug by federal laboratories. The unambiguous identification of fentanyl‐related substances (FRS) is challenging due to the absence or low abundance of a molecular ion in a typical gas chromatography‐mass spectrometry (GC‐MS) analysis and due to a low number of fragment ions that are similar among the many potential isomers of FRS. This study describes the utility of a previously reported gas chromatography‐infrared (GC‐IR) library for the identification of FRS within a blind, interlaboratory study (ILS) involving seven forensic laboratories. Twenty FRS reference materials, including those with isomer pairs in the library, were selected based on either their presence in the NIST library and/or some similarity of the mass spectra information produced. The ILS participants were requested to use the Florida International University (FIU) GC‐MS and GC‐IR libraries supplied by FIU to search for matches to their unknown spectra generated from in‐house GC‐MS and GC‐IR analysis. The laboratories reported improvement in the positive identification of unknown FRS from ~75% using GC‐MS alone to 100% correct identification using GC‐IR analysis. One laboratory participant used solid phase IR analysis, which produced spectra incompatible with the vapor phase GC‐IR library to generate a good comparison spectrum. However, this improved when searched against a solid phase IR library. [ABSTRACT FROM AUTHOR]

For successful elucidation of a food-borne infection chain, the availability of high-quality sequencing data from suspected microbial contaminants is a prerequisite. Commonly, those investigations are a joint effort undertaken by different laboratories and institutes. To analyze the extent of variability introduced by differing wet-lab procedures on the quality of the sequence data we conducted an interlaboratory study, involving four bacterial pathogens, which account for the majority of food-related bacterial infections: Campylobacter spp., Shiga toxin-producing Escherichia coli, Listeria monocytogenes, and Salmonella enterica. The participants, ranging from German federal research institutes, federal state laboratories to universities and companies, were asked to follow their routine in-house protocols for short-read sequencing of 10 cultures and one isolated bacterial DNA per species. Sequence and assembly quality were then analyzed centrally. Variations within isolate samples were detected with SNP and cgMLST calling. Overall, we found that the quality of Illumina raw sequence data was high with little overall variability, with one exception, attributed to a specific library preparation kit. The variability of Ion Torrent data was higher, independent of the investigated species. For cgMLST and SNP analysis results, we found that technological sequencing artefacts could be reduced by the use of filters, and that SNP analysis was more suited than cgMLST to compare data of different contributors. Regarding the four species, a minority of Campylobacter isolate data showed the in comparison highest divergence with regard to sequence type and cgMLST analysis. We additionally compared the assembler SPAdes and SKESA for their performance on the Illumina data sets of the different species and library preparation methods and found overall similar assembly quality metrics and cgMLST statistics.

Glycosylation is a topic of intense current interest in the development of biopharmaceuticals because it is related to drug safety and efficacy. This work describes results of an interlaboratory study on the glycosylation of the Primary Sample (PS) of NISTmAb, a monoclonal antibody reference material. Seventy-six laboratories from industry, university, research, government, and hospital sectors in Europe, North America, Asia, and Australia submitted a total of 103 reports on glycan distributions. The principal objective of this study was to report and compare results for the full range of analytical methods presently used in the glycosylation analysis of mAbs. Therefore, participation was unrestricted, with laboratories choosing their own measurement techniques. Protein glycosylation was determined in various ways, including at the level of intact mAb, protein fragments, glycopeptides, or released glycans, using a wide variety of methods for derivatization, separation, identification, and quantification. Consequently, the diversity of results was enormous, with the number of glycan compositions identified by each laboratory ranging from 4 to 48. In total, one hundred sixteen glycan compositions were reported, of which 57 compositions could be assigned consensus abundance values. These consensus medians provide community-derived values for NISTmAb PS. Agreement with the consensus medians did not depend on the specific method or laboratory type. The study provides a view of the current state-of-the-art for biologic glycosylation measurement and suggests a clear need for harmonization of glycosylation analysis methods.

BackgroundMedical device manufacturers are obliged to prove the biocompatibility of their products when they come into contact with the human body. The requirements for the biological evaluation of medical devices are specified by the international standard series ISO 10993. Part five of this series describes the performance of in vitro cytotoxicity tests. This test evaluates the effects of medical device use on cell health. The existence of the specific standard suggests that the tests will produce reliable and comparable results. However, the ISO 10993-5 offers wide latitude in the test specifications. In the past, we noticed inconsistencies of the results from different laboratories.ObjectiveTo determine if the specifications of the standard ISO 10993-5 are explicit to ensure the comparability of test results and, if not, identify potential influencing factors.MethodsAn interlaboratory comparison was conducted for the in vitro cytotoxicity test according to ISO 10993-5. Fifty-two international laboratories evaluated the cytotoxicity for two unknown samples. One was polyethylene (PE) tubing, which is expected to be non-cytotoxic and the other was polyvinyl chloride (PVC) tubing, for which a cytotoxic potential was presumed. All laboratories were asked to perform an elution test with predefined extraction specifications. The other test parameters were freely chosen by the laboratories according to the guidelines set by the standard.ResultsTo our surprise only 58 percent of the participating laboratories identified the cytotoxic potential of both materials as expected. Particularly for PVC a considerable variation of the results between the laboratories was observed [mean = 43 ± 30 (SD), min = 0, max = 100]. We showed that ten percent serum supplementation to the extraction medium, as well as longer incubation of the cells with the extract, greatly increased the test sensitivity for PVC.ConclusionThe results clearly show that the specifications set by the ISO 10993-5 are not explicit enough to obtain comparable results for an identical medical device. To set requirements that ensure reliable cytotoxicity assessments, further research will be necessary to identify the best test conditions for specific materials and/or devices and the standard needs to be revised accordingly.

Many statistical methods (estimators) are available for estimating the consensus value (or average effect) and heterogeneity variance in interlaboratory studies or meta‐analyses. These estimators are all valid because they are developed from or supported by certain statistical principles. However, no estimator can be perfect and must have error or uncertainty (known as estimator uncertainty). For a given dataset, the consensus value and heterogeneity variance given by different estimators can often differ significantly. Consequently, the choice of different estimators can affect the conclusion of an interlaboratory study or meta‐analysis. However, there is no universally accepted metric for determining which estimator is optimal among a set of candidate estimators. Instead of selecting and using a single estimator, this paper proposes an estimator‐averaging approach to combine a set of individual estimators. The final averaged estimator is a linear combination of individual estimators, which accounts for three sources of uncertainties including the estimator uncertainty. Monte Carlo simulations were performed to examine the long‐run performance of four individual estimators and the proposed averaged estimators. A case study: the determination of the Newtonian constant of gravitation is presented, where 10 individual estimators (eight frequentist weighted average methods and two Bayesian methods) are combined using the proposed estimator‐averaging approach. [ABSTRACT FROM AUTHOR]

This paper reports the results of an international interlaboratory study sponsored by the Versailles Project on Advanced Materials and Standards (VAMAS) and led by the National Institute of Standards and Technology (NIST) on the measurement of water vapor sorption isotherms at 25 °C on a pelletized nanoporous carbon (BAM-P109, a certified reference material). Thirteen laboratories participated in the study and contributed nine pure water vapor isotherms and four relative humidity isotherms, using nitrogen as the carrier gas. From these data, reference isotherms, along with the 95% uncertainty interval (Uk=2), were determined and are reported in a tabular format. [ABSTRACT FROM AUTHOR]

In the quest to market increasingly safer and more potent biotherapeutic proteins, the concept of the multi-attribute method (MAM) has emerged from biopharmaceutical companies to boost the quality-by-design process development. MAM strategies rely on state-of-the-art analytical workflows based on liquid chromatography coupled to mass spectrometry (LC–MS) to identify and quantify a selected series of critical quality attributes (CQA) in a single assay. Here, we aimed at evaluating the repeatability and robustness of a benchtop LC–MS platform along with bioinformatics data treatment pipelines for peptide mapping-based MAM studies using standardized LC–MS methods, with the objective to benchmark MAM methods across laboratories, taking nivolumab as a case study. Our results evidence strong interlaboratory consistency across LC–MS platforms for all CQAs (i.e., deamidation, oxidation, lysine clipping and glycosylation). In addition, our work uniquely highlights the crucial role of bioinformatics postprocessing in MAM studies, especially for low-abundant species quantification. Altogether, we believe that MAM has fostered the development of routine, robust, easy-to-use LC–MS platforms for high-throughput determination of major CQAs in a regulated environment. [ABSTRACT FROM AUTHOR]

The Particle Measurement Programme Informal Working Group (PMP-IWG) coordinated a global interlaboratory study (ILS) on brake wear particle emissions with the participation of 16 testing facilities. Two articles present the main outcomes of the ILS: (I) Particulate matter mass (PM), and (II) Particle Number (PN) emissions. The test matrix covered a wide variety of brake systems and configurations. The tested disc brakes were found to emit PM2.5 and PM10 that varied between 0.8–4.0 mg/km and 2.2–9.5 mg/km per brake, respectively, depending on the type of brake and the applied testing load. The drum brake emitted much lower PM due to its enclosed nature. Almost 37–45% of the emitted PM falls in the fine particle size with this fraction being higher for the drum brake. On the other hand, almost 50–65% of the total brake mass loss falls in particle sizes larger than 10 μm or gets lost before being measured. The most important loss mechanisms for PM in the proposed layout are being discussed. Finally, the PM measurement variability and lab-to-lab reproducibility are investigated. [ABSTRACT FROM AUTHOR]

The Particle Measurement Programme (PMP) informal working group co-ordinated a global interlaboratory study (ILS) on brake wear particle emissions with the participation of 16 laboratories in 2021. Two articles present the results of the ILS: (I) particulate matter mass (PM) and (II) particle number (PN) emissions. The test matrix covered different brake systems, including ECE and NAO pad materials with grey cast iron discs and a drum brake. Regarding PN, the study measured the total particle number from approximately 10 nm to 2.5 µm (TPN). Some testing facilities measured solid particle number emissions (SPN) in parallel. The mean TPN concentrations ranged from 9.1 × 108 #/km/brake to 1.1 × 1010 #/km/brake. TPN and SPN emission levels were comparable, except for one lab that measured very high volatile particle emissions for one brake system. The minimum and maximum SPN emissions for a given brake differed by a factor of 2.5 ± 0.5, comparable to data from exhaust SPN ILS measurements. This article provides an overview of lessons learned and subsequent measures incorporated in an upcoming global technical regulation to reduce measurement variability when sampling and measuring brake particle emissions for light-duty vehicles up to 3.5 t. [ABSTRACT FROM AUTHOR]

Embryonic zebrafish represent a useful test system to screen substances for their ability to perturb development. The exposure scenarios, endpoints captured, and data analysis vary among the laboratories who conduct screening. A lack of harmonization impedes the comparison of the substance potency and toxicity outcomes across laboratories and may hinder the broader adoption of this model for regulatory use. The Systematic Evaluation of the Application of Zebrafish in Toxicology (SEAZIT) initiative was developed to investigate the sources of variability in toxicity testing. This initiative involved an interlaboratory study to determine whether experimental parameters altered the developmental toxicity of a set of 42 substances (3 tested in duplicate) in three diverse laboratories. An initial dose-range-finding study using in-house protocols was followed by a definitive study using four experimental conditions: chorion-on and chorion-off using both static and static renewal exposures. We observed reasonable agreement across the three laboratories as 33 of 42 test substances (78.6%) had the same activity call. However, the differences in potency seen using variable in-house protocols emphasizes the importance of harmonization of the exposure variables under evaluation in the second phase of this study. The outcome of the Def will facilitate future practical discussions on harmonization within the zebrafish research community.

Determination of ornithine in bunashimeji mushrooms (Hypsizygus marmoreus) was examined. Quantitative values did not differ whether or not sample hydrolysis was implemented, and thus hydrolysis was not performed. The sample solution was obtained by shaking extraction with dilute hydrochloric acid, centrifugation, and filtration. Sample measurement using LC-MS / MS, HPLC (post-column derivatization method, HPLC (post)) and HPLC (pre-column derivatization method, HPLC (pre)) revealed a high quantitative value for HPLC (pre), and a significant difference was observed. It is presumed that pre-column derivatization increased the matrix effects. Therefore, measurement using LC-MS / MS or HPLC (post) was selected. To validate this analytical method, we conducted an interlaboratory study in which 10 participating laboratories independently analyzed five test materials (five pairs of blind duplicates). The repeatability (RSDr) and reproducibility (RSDR) were 1.4~3.7 % and 3.2~7.1 %, respectively, in a concentration range from 6.7 × 10² to 1.9 × 10³ (mg/kg fresh matter). The HorRat values were 0.61~1.3, indicating acceptable precision. This method is simple, versatile and can be used in many laboratories. [ABSTRACT FROM AUTHOR]

From reading William John "Jack" Youden's books and articles, Youden (1900-1971), an analytical chemist, becomes an applied statistician by the time he joins the National Bureau of Standards (NBS) in 1948. This article traces his transition from chemist to applied statistician and what his body of work mostly at NBS (1948-1965) demonstrates about his practice of statistics and the role that applied statistical research plays in it. There is much we can learn from a master applied statistician. [ABSTRACT FROM AUTHOR]

A collaborative interlaboratory study of the method of direct determination of volatile compounds in spirit drinks and alcoholic products was performed. The proposed method employs ethanol, the major volatile component of an alcoholic product, as an internal standard. For the experiment realization, 9 laboratories from 4 countries – Belarus, Czech Republic, Turkey, Russia – were supplied with standard solutions for gas chromatographic measurements. Five aqueous ethanol 40 % (v/v) standard solutions containing target compounds in concentrations ranging from 10 to 400 mg/L of absolute alcohol were gravimetrically prepared and delivered to the participants. The interlaboratory study was evaluated according to the ISO 5725 standards and the «EuroChem» guide. The repeatability limits (within-laboratory precision) varied between 0.4 and 7.5 % for all samples and compounds, showing a sufficiently high repeatability of the method. The reproducibility limits (between-laboratory precision) were found to vary within a satisfactory range of 0.5–10.0 %. Precision of the method was well within the range predicted by the Horwitz equation for all analytes. In the study experimental estimation of trueness was performed for the first time. Analysis of the obtained results showed that the bias of the method is insignificant at the significance level 5 %. The experimentally determined concentrations of the analytes compared well to the gravimetrical values, thus showing very satisfactory accuracy of the method. The results of the interlaboratory study confirmed that the method «ethanol as internal standard» is robust and reliable and can be used as a standard method for the determination of volatile compounds in water-ethanol samples. Moreover, this method can be validated in any one laboratory without performing additional experimental studies based on the results obtained by validation of the traditional method.

Biopharmaceuticals such as monoclonal antibodies are required to be rigorously characterized using a wide range of analytical methods. Various material properties must be characterized and well controlled to assure that clinically relevant features and critical quality attributes are maintained. A thorough understanding of analytical method performance metrics, particularly emerging methods designed to address measurement gaps, is required to assure methods are appropriate for their intended use in assuring drug safety, stability, and functional activity. To this end, a series of interlaboratory studies have been conducted using NISTmAb, a biopharmaceutical-representative and publicly available monoclonal antibody test material, to report on state-of-the-art method performance, harmonize best practices, and inform on potential gaps in the analytical measurement infrastructure. Reported here is a summary of the study designs, results, and future perspectives revealed from these interlaboratory studies which focused on primary structure, post-translational modifications, and higher order structure measurements currently employed during biopharmaceutical development.

A laboratory method to simulate natural exposure of roofing materials has been reported in a companion article. In the current article, we describe the results of an international, nine-participant interlaboratory study (ILS) conducted in accordance with ASTM Standard E691-09 to establish the precision and reproducibility of this protocol. The accelerated soiling and weathering method was applied four times by each laboratory to replicate coupons of 12 products representing a wide variety of roofing categories (single-ply membrane, factory-applied coating (on metal), bare metal, field-applied coating, asphalt shingle, modified-bitumen cap sheet, clay tile, and concrete tile). Participants reported initial and laboratory-aged values of solar reflectance and thermal emittance. Measured solar reflectances were consistent within and across eight of the nine participating laboratories. Measured thermal emittances reported by six participants exhibited comparable consistency. For solar reflectance, the accelerated aging method is both repeatable and reproducible within an acceptable range of standard deviations: the repeatability standard deviation sr ranged from 0.008 to 0.015 (relative standard deviation of 1.2-2.1%) and the reproducibility standard deviation sR ranged from 0.022 to 0.036 (relative standard deviation of 3.2-5.8%). The ILS confirmed that the accelerated aging method can be reproduced by multiple independent laboratories with acceptable precision. This study supports the adoption of the accelerated aging practice to speed the evaluation and performance rating of new cool roofing materials.

A laboratory method to simulate natural exposure of roofing materials has been reported in a companion article. In the current article, we describe the results of an international, nine-participant interlaboratory study (ILS) conducted in accordance with ASTM Standard E691-09 to establish the precision and reproducibility of this protocol. The accelerated soiling and weathering method was applied four times by each laboratory to replicate coupons of 12 products representing a wide variety of roofing categories (single-ply membrane, factory-applied coating (on metal), bare metal, field-applied coating, asphalt shingle, modified-bitumen cap sheet, clay tile, and concrete tile). Participants reported initial and laboratory-aged values of solar reflectance and thermal emittance. Measured solar reflectances were consistent within and across eight of the nine participating laboratories. Measured thermal emittances reported by six participants exhibited comparable consistency. For solar reflectance, the accelerated aging method is both repeatable and reproducible within an acceptable range of standard deviations: the repeatability standard deviation sr ranged from 0.008 to 0.015 (relative standard deviation of 1.2-2.1%) and the reproducibility standard deviation sR ranged from 0.022 to 0.036 (relative standard deviation of 3.2-5.8%). The ILS confirmed that the accelerated aging method can be reproduced by multiple independent laboratories with acceptable precision. This study supports the adoption of the accelerated aging practice to speed the evaluation and performance rating of new cool roofing materials.

This paper describes the evaluation of petrographic textures in char and activated carbon derived from coal, coal by-products and biomass, formed during carbonization and activation processes. This work represents the results of interlaboratory exercises from 2016 to 2022 of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology. The interlaboratory exercises were run on photomicrograph samples. For textural characterization of carbon materials, the existing American Society for Testing and Materials (ASTM) classification system for metallurgical coke was applied. Morphological differences were evaluated in 29 carbon material types, including 22 char samples, and 7 activated carbon (AC) samples obtained experimentally using conventional direct/indirect and microwave heating technologies. This approach gives an extended view on the identification of microporous carbons, and how a certain heat treatment develops a certain optical texture and structure in a raw material. The requested evaluation of carbon materials was related to their porosity, origin, extent, and characteristics, which are particular to each carbon material type. Because carbon matrices can form a wide range of optical textures during heat treatment it is important to demonstrate which carbon occurrences will have a crucial role in industrial applications dominated by adsorption phenomena. The interlaboratory exercises included 17 participants from 14 laboratories. Four sets of digital black and white and colour photomicrographs were distributed, which in total comprised 184 fields of different types of carbon material. The results were evaluated based on four levels: (i) optical texture (isotropic/anisotropic), (ii) optical type and size (punctiform, mosaic, fiber, ribbon, domain), iii) morphology (porous, non-porous/massive), and (iv) particle origin (precursor type). The statistical method applied to evaluate the results was based on "raw agreement indices". Comparative analyses of the average values of the level of overall agreement showed homogeneity in the results, the mean value was 89%, with a minimum value of 87% and a maximum value of 91% for those who participated in at least three out of four exercises. • Char and activated carbon derived from coal and biomass are evaluated. • Classification of metallurgical coke optical texture is used for carbon materials. • Interlaboratory exercise results prove the homogeneity of participants' answers. • Results show a level of overall agreement mean value of 89%. • Optical microscopy can be used as a quality control method for carbon materials. [ABSTRACT FROM AUTHOR]

The performance characteristics of a multi-analyte method for the determination of all 10 carotenoids authorised as feed additives within the EU were assessed via an interlaboratory study. The analytical method is based on reversed phase high performance liquid chromatography (RP-HPLC) coupled to an optical detector set at 410 nm. The analysis is particularly challenging due to the presence of various stereoisomers of each carotenoid, and the use of these compounds via natural or synthetic formulations, requiring a special sample preparation. EU regulations specifying the conditions of use set legal limits for these substances in compound feedingstuffs ranging from 6 mg kg−1 to 138 mg kg−1, depending on the individual carotenoid and the target animal for which the feed is supplemented with this carotenoid. The purpose of the multi-analyte method validated in this paper is to facilitate the monitoring of carotenoids at relevant levels when used as feed additives in compound feedingstuffs and pre-mixtures. The interlaboratory study delivered precision data for 43 different analyte/mass fraction/matrix combinations, covering a mass fraction range of the target analytes from 2.6 mg kg−1 to 3861 mg kg−1. The relative standard deviations for repeatability (RSDr) varied from 2.2 to 16.2 % with a mean value of 6 %, while the relative standard deviations for reproducibility (RSDR) varied from 6.8 to 39 % with a mean value of 21 %. Given the broad scope of the method covering 10 carotenoids added to compound feedingstuffs and pre-mixtures via different formulations, this multi-analyte method is considered fit for the intended purpose. [ABSTRACT FROM AUTHOR]

We compared the consistency, accuracy and reproducibility of next-generation short read sequencing between ten laboratories involved in food safety (research institutes, state laboratories, universities and companies) from Germany and Austria. Participants were asked to sequence six DNA samples of three bacterial species (Campylobacter jejuni, Listeria monocytogenes and Salmonella enterica) in duplicate, according to their routine in-house sequencing protocol. Four different types of Illumina sequencing platforms (MiSeq, NextSeq, iSeq, NovaSeq) and one Ion Torrent sequencing instrument (S5) were involved in the study. Sequence quality parameters were determined for all data sets and centrally compared between laboratories. SNP and cgMLST calling were performed to assess the reproducibility of sequence data collected for individual samples. Overall, we found Illumina short read data to be more accurate (higher base calling accuracy, fewer miss-assemblies) and consistent (little variability between independent sequencing runs within a laboratory) than Ion Torrent sequence data, with little variation between the different Illumina instruments. Two laboratories with Illumina instruments submitted sequence data with lower quality, probably due to the use of a library preparation kit, which shows difficulty in sequencing low GC genome regions. Differences in data quality were more evident after assembling short reads into genome assemblies, with Ion Torrent assemblies featuring a great number of allele differences to Illumina assemblies. Clonality of samples was confirmed through SNP calling, which proved to be a more suitable method for an integrated data analysis of Illumina and Ion Torrent data sets in this study.

Background: The quality of Digital Volume Correlation (DVC) full-field displacement measurements depends directly on the characteristics of the X-ray Computed Tomography (XCT) equipment, and scan procedures used to acquire the tomographic images. Objective: We seek to experimentally study the effects of XCT equipment and tomographic scan procedures on the quality of these images for DVC analysis, and to survey the level of DVC error that may be achieved using standard XCT operating procedures. Methods: Six participants in an interlaboratory study acquired high-quality XCT scans of a syntactic foam before and after rigid body motion. The resulting images were correlated using commercial DVC software to quantify error sources due to random image noise, reconstruction artifacts, as well as systematic spatial or temporal distortion. Results: In the absence of rigid body motion, the standard deviation of the displacement measurements ranged from 0.012 to 0.043 voxels using a moderate subvolume size, indicating that subvoxel measurement resolution could readily be achieved with a variety of XCT equipment and scan recipes. Comparison of consecutive scans without rigid body motion showed transient dilatational displacement gradients due to self-heating of the X-ray source and/or thermal expansion of the foam. Evaluation of the scans after rigid body motion showed significant, machine-specific spatial distortion in the displacement fields of up to 0.5 voxels; new approaches to remove this error need to be developed. Conclusions: Analysis of the scan protocols used in the interlaboratory study, as well as a complementary parametric sensitivity study, showed that the DVC error was strongly influenced by the XCT equipment, but could be mitigated by adjusting the total scan duration. [ABSTRACT FROM AUTHOR]

In forensic analyses, determining the level of consensus among examiners for hair comparison conclusions and ancestry identifications is important for assessing the scientific validity of microscopical hair examinations. Here, we present data from an interlaboratory study on the accuracy of microscopical hair comparisons among a subset of experienced hair examiners currently analyzing hair in forensic laboratories across the United States. We examined how well microscopical analysis of hair can reliably be used to differentiate hair samples, many of which were macroscopically similar. Using cut hair samples, many sharing similar macroscopic and microscopic features, collected from individuals who share the same mitochondrial haplogroup as an indication of genetic relatedness, we tested multiple aspects that could impact hair comparisons. This research tested the extent to which morphological features related to ancestry and hair length influence conclusions. Microscopical hair examinations yielded accurate assessments of inclusion/exclusion relative to the reference samples among 85% of the pairwise comparisons. We found shorter hairs had reduced levels of accuracy and hairs from populations examiners were not familiar with may have impacted their ability to resolve features. The reliability of ancestry determinations is not yet clear, but we found indications that the existing categories are only somewhat related to current ethnic and genetic variation. Our results provide support for the continued utility of microscopical comparison of hairs within forensic laboratories and to advocate for a combined analytical approach using both microscopical analysis and mtDNA data on all forensic analyses of hair. [ABSTRACT FROM AUTHOR]

This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess methane adsorption isotherms on NIST Reference Material RM 8850 (Zeolite Y), at 25 °C up to 7.5 MPa. Twenty laboratories participated in the study and contributed over one-hundred adsorption isotherms of methane on Zeolite Y. From these data, an empirical reference equation was determined, along with a 95% uncertainty interval (Uk=2). By requiring participants to replicate a high-pressure reference isotherm for carbon dioxide adsorption on NIST Reference Material RM 8852 (ZSM-5), this interlaboratory study also demonstrated the usefulness of reference isotherms in evaluating the performance of high-pressure adsorption experiments. [ABSTRACT FROM AUTHOR]

We compared the consistency, accuracy and reproducibility of next-generation short read sequencing between ten laboratories involved in food safety (research institutes, state laboratories, universities and companies) from Germany and Austria. Participants were asked to sequence six DNA samples of three bacterial species (Campylobacter jejuni , Listeria monocytogenes and Salmonella enterica) in duplicate, according to their routine in-house sequencing protocol. Four different types of Illumina sequencing platforms (MiSeq, NextSeq, iSeq, NovaSeq) and one Ion Torrent sequencing instrument (S5) were involved in the study. Sequence quality parameters were determined for all data sets and centrally compared between laboratories. SNP and cgMLST calling were performed to assess the reproducibility of sequence data collected for individual samples. Overall, we found Illumina short read data to be more accurate (higher base calling accuracy, fewer miss-assemblies) and consistent (little variability between independent sequencing runs within a laboratory) than Ion Torrent sequence data, with little variation between the different Illumina instruments. Two laboratories with Illumina instruments submitted sequence data with lower quality, probably due to the use of a library preparation kit, which shows difficulty in sequencing low GC genome regions. Differences in data quality were more evident after assembling short reads into genome assemblies, with Ion Torrent assemblies featuring a great number of allele differences to Illumina assemblies. Clonality of samples was confirmed through SNP calling, which proved to be a more suitable method for an integrated data analysis of Illumina and Ion Torrent data sets in this study. [ABSTRACT FROM AUTHOR]

Escherichia albertii is an emerging enteropathogen. Although E. albertii -specific detection and isolation methods have been developed, their efficiency on food samples have not yet been systematically studied. To establish a series of effective methods for detecting E. albertii in food, an interlaboratory study was conducted in 11 laboratories using enrichment with modified E. coli broth supplemented with cefixime and tellurite (CT-mEC), real-time PCR assay, and plating on four kinds of selective agars. This study focused on the detection efficiency of an E. albertii -specific real-time PCR assay (EA-rtPCR) and plating on deoxycholate hydrogen sulfide lactose agar (DHL), MacConkey agar (MAC), DHL supplemented with rhamnose and xylose (RX-DHL), and MAC supplemented with rhamnose and xylose (RX-MAC). Chicken and bean sprout samples were inoculated with E. albertii either at 17.7 CFU/25 g (low inoculation level) or 88.5 CFU/25 g (high inoculation level), and uninoculated samples were used as controls. The sensitivity of EA-rtPCR was 1.000 for chicken and bean sprout samples inoculated with E. albertii at low and high inoculation levels. The Ct values of bean sprout samples were higher than those of the chicken samples. Analysis of microbial distribution by 16S rRNA gene amplicon sequencing in enriched cultures of bean sprout samples showed that approximately >96 % of the population comprised unidentified genus of family Enterobacteriaceae and genus Acinetobacter in samples which E. albertii was not isolated. The sensitivity of the plating methods for chicken and bean sprout samples inoculated with a high inoculation level of E. albertii was 1.000 and 0.848–0.970, respectively. The sensitivity of the plating methods for chicken and bean sprout samples inoculated with a low inoculation level of E. albertii was 0.939–1.000 and 0.515–0.727, respectively. The E. albertii -positive rate in all colonies isolated in this study was 89–90 % in RX-DHL and RX-MAC, and 64 and 44 % in DHL and MAC, respectively. Therefore, the sensitivity of RX-supplemented agar was higher than that of the agars without these sugars. Using a combination of enrichment in CT-mEC and E. albertii isolation on selective agars supplemented with RX, E. albertii at an inoculation level of over 17.5 CFU/25 g of food was detected with a sensitivity of 1.000 and 0.667–0.727 in chicken and bean sprouts, respectively. Therefore, screening for E. albertii -specific genes using EA-rtPCR followed by isolation with RX-DHL or RX-MAC is an efficient method for E. albertii detection in food. • An interlaboratory study with E. albertii was conducted with 11 laboratories. • Sensitivities of >0.667 were detected in E. albertii (17.5 CFU)-inoculated foods. • Food matrix might influence the isolation of E. albertii. • Selective agars of RX-DHL and RX-MAC were superior than DHL and MAC. • EA-rtPCR-screening followed by isolation is efficient for E. albertii detection. [ABSTRACT FROM AUTHOR]

Short-chained chlorinated paraffins (SCCP) and medium-chained chlorinated paraffins (MCCPs) are two of the main groups currently used to classify chlorinated paraffins (CPs). Since only SCCPs have been restricted by the Stockholm Convention, a robust but selective analysis with comparable results especially for SCCPs, but also for all other CPs is needed to ensure official controls to enforce future resulting food legislation. Failing that, expansion of the legislation towards total CP or to include MCCPs and other main groups needs to be considered. A survey taken amongst official and private laboratories in the EU and beyond revealed a large variety of methods currently in use or in planning stages for CP analysis. In June 2017, spiked samples of coconut fat were sent to 27 registered participants from 18 countries for an interlaboratory study. In July 2018, lard samples spiked with CPs, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were sent to 13 registered participants from 11 countries. In both cases, more than 55% of participants had a satisfactory overall performance (AZ2<3, σ = 25%). The greatest challenge seemed to be correct quantification of SCCP and MCCP mixtures, hinting at future problems with the through biodegradation much more complex food samples. Of the wide variety of methods being used, GC-MS based methods were favoured. Both HRMS and LRMS methods were able to perform satisfactorily. Identified influencing factors included choice of instrument, choice of standards and data processing strategy. These factors need to be further investigated in future interlaboratory studies. Image 1 • First interlaboratory study scheme on CPs in food matrices. • Method survey shows effectivity of quantification and instruments. • More than 55% overall satisfactory participation. • Problems with mixtures of SCCPs and MCCPs were observed for all methods. • High- and low-resolution instrumentation was represented. [ABSTRACT FROM AUTHOR]

The relative contribution of brake emissions to traffic-induced ambient Particulate Matter (PM) concentrations has increased over the last decade. Nowadays, vehicles’ brakes are recognised as an important source of non-exhaust emissions. Up to now, no standardised method for measuring brake particle emissions exists. For that reason, the Particle Measurement Programme (PMP) group has been working on the development of a commonly accepted method for sampling and measuring brake particle emissions. The applied braking cycle is an integral part of the overall methodology. In this article, we present the results of an interlaboratory study exploring the capacity of existing dynamometer setups to accurately execute the novel Worldwide Harmonised Light-Duty Vehicles Test Procedure (WLTP)–brake cycle. The measurements took place at eight locations in Europe and the United States. Having several dynamometers available enabled the coordination and execution of the intended exercise, to determine the sources of variability and provide recommendations for the correct application of the WLTP–brake cycle on the dyno. A systematic testing schedule was applied, followed by a thorough statistical analysis of the essential parameters according to the ISO 5725 standards series. The application of different control programmes influenced the correct replication of the cycle. Speed control turned out to be more accurate and precise than deceleration control. A crucial output of this interlaboratory study was the quantification of standard deviations for repeatability (between repeats), sample effect (between tests), laboratory effect (between facilities), and total reproducibility. Three critical aspects of the statistical analysis were: (i) The use of methods for heterogeneous materials; (ii) robust algorithms to reduce the artificial increase in variability from values with significant deviation from the normal distribution; and (iii) the reliance on the graphical representation of results for ease of understanding. Even if the study of brake emissions remained out of the scope of the current exercise, useful conclusions are drawn from the analysis of the temperature profile of the WLTP–brake cycle. Urban braking events are generally correlated to lower disc temperature. Other parameters affecting the brake temperature profile include the correct application of soak times, the temperature measurement method, the proper conditioning of incoming cooling air and the adjustment of the cooling airspeed.

Abstract The methods for the detection and enumeration of Enterobacteriaceae , described in EN ISO 21528, parts 1 and 2, were validated by order of the European Commission under the mandate M/381. Fourteen laboratories from seven European countries participated in the collaborative trials, organized by The Netherlands Food and Consumer Product Safety Authority (Wageningen/Utrecht, The Netherlands). Five different matrices from different food categories were selected to be tested in the collaborative trials, in order to validate the method horizontally, according to ISO 16140. The matrices included meat, tiramisu, infant formula, liquid egg, smoked salmon (detection method only) and animal feed (enumeration method only). The raw meat and liquid egg were naturally contaminated and the other matrices were artificially contaminated with a cocktail of four different Enterobacteriaceae strains. The samples used in the trial were tested for homogeneity and stability before distribution. The method for detection of Enterobacteriaceae showed a specificity and sensitivity above 95% for all matrices. The method for the enumeration had a repeatability limit r of 0.37 (expressed as a difference between log 10 -transformed test results) and a reproducibility limit R of 0.87 (expressed as a difference between log 10 -transformed test results). The validation data were incorporated in the newly published ISO standards EN ISO 21528:2017- Microbiology of the food chain - Horizontal methods for the detection and enumeration of Enterobacteriaceae - Part 1: Detection method, and Part 2: Colony-count technique. [ABSTRACT FROM AUTHOR]

Abstract EN ISO 10273 method for the detection of pathogenic Yersinia enterocolitica in foods was validated in the project Mandate M/381 funded by European Commission. A total of 14 laboratories from five European countries participated in the interlaboratory study (ILS) organized during 2013 and 2014. Before the ILS, the method was revised by an international group of experts and the performance of the revised method was assessed in an ILS study. The results are published as a part of the standard EN ISO 10273 revision. The study included three rounds with different sample types; raw milk, iceberg lettuce and minced meat, inoculated with a low and high level of pathogenic Y. enterocolitica strains representing major pathogenic bioserotypes 4/O:3 and 2/O:9. The homogeneity and stability of the samples were verified before dispatching them to the laboratories. The results demonstrated the method sensitivity of 96% in raw milk, 97% in minced meat, and 98% in lettuce at high inoculation level of pathogenic Y. enterocolitica. The specificity was 100% in raw milk, 96% in minced meat, and 98% in lettuce. The level of detection, LOD 50 , varied between study rounds, being 9.4 CFU/25 ml in raw milk, 9.9 CFU/25 g in minced meat and 63 CFU/25 g in lettuce samples. During the study, confirmation by using real-time PCR method ISO/TS 18867 together with pyrazinamidase testing was also validated, as alternative to conventional biochemical confirmation. When comparing different isolation steps used in the revised method during the study rounds, PSB enrichment and plating on CIN after alkaline (KOH) treatment showed the highest sensitivity (52–92%) in raw milk and minced meat samples. In lettuce samples, however, ITC with KOH treatment before plating on CIN showed higher sensitivity (64% at low level; 82% at high level) than plating on CIN from PSB with KOH treatment (44% at low level; 74% at high level). Statistical analysis of different isolation steps supported the use of two enrichment media, PSB and ITC, in the revised method. Recovery of pathogenic Y. enterocolitica on CIN was most efficient after KOH treatment and, based on the analysis, plating on CIN agar without KOH treatment could be left as optional procedure in the method. [ABSTRACT FROM AUTHOR]

A high‐resolution 31P NMR method for determining the concentration of phospholipid (PL) species in krill oil was proficiency tested using an international interlaboratory study. Fourteen laboratories from five countries tested five different krill oil samples providing 17 datasets. Krill oil samples were prepared by the organizer using liquid–liquid extraction and sent to the participants who ran the nuclear magnetic resonance (NMR) analysis and evaluated the spectra. The relative standard deviation (RSD) among all the results provided by the participants varied between 2.1% and 3.3% for the phosphatidylcholine (PtdCho) content and between 2.8% and 12.3% for the sum of other PL. Afterward, an automated procedure was applied to all collected NMR data, which significantly improved the RSD values and provided reliable quantitative results for specific PL (PtdCho, 1‐lysophosphatidylcholine [LPC], 2‐LPS, PtdEtn, acylphosphatidylethanolamine [APE], and lysophosphatidylethanolamine [LPE]). The RSD varied between 1.6% and 2.7% for PtdCho and between 1.6% and 2.9% for the total phosphorus. Higher but acceptable values were obtained for 1‐LPC (5.1% to 8.9%), PtdEtn (7.0% to 10.5%), and LPE (5.7% to 16.5%) due to their small concentrations. The influence of different magnetic field strengths (400–600 MHz), probes, and slight differences in acquisition parameters was assessed as nonsignificant. PtdCho hydrolysis during 14 weeks before measurements was the major factor that affects the result distribution. This method was submitted to the AOCS to become an official AOCS method for krill oil analysis. [ABSTRACT FROM AUTHOR]

Highlights • Results are described for two interlaboratory studies, NIST MIX05 and MIX13. • With MIX05, 69 laboratories interpreted two-person DNA mixtures from four mock sexual assault cases with different contributor ratios. • In MIX13, 108 laboratories evaluated five case scenarios involving two, three, or four contributors. • Study design, variation observed among and within laboratories, and lessons learned are described. Abstract Interlaboratory studies are a type of collaborative exercise in which many laboratories are presented with the same set of data to interpret, and the results they produce are examined to get a "big picture" view of the effectiveness and accuracy of analytical protocols used across participating laboratories. In 2005 and again in 2013, the Applied Genetics Group of the National Institute of Standards and Technology (NIST) conducted interlaboratory studies involving DNA mixture interpretation. In the 2005 NIST MIX05 study, 69 laboratories interpreted data in the form of electropherograms of two-person DNA mixtures representing four different mock sexual assault cases with different contributor ratios. In the 2013 NIST MIX13 study,108 laboratories interpreted electropherogram data for five different case scenarios involving two, three, or four contributors, with some of the contributors potentially related. This paper describes the design of these studies, the variations observed among laboratory results, and lessons learned. [ABSTRACT FROM AUTHOR]

Highlights • The design of the interlaboratory exercise NIST MIX13 is discussed. • NIST MIX13 interlaboratory is analyzed using four different probabilistic genotyping software. • PG performs well on all five cases. • For case 3, the background information suggests assuming victim and consensual partner. • Three of the PG include the constructed reference 5C (a non-donor) in over engineered case 5. Abstract MIX13 was an interlaboratory exercise directed by NIST in 2013. The goal of the exercise was to evaluate the general state of interpretation methods in use at the time across the forensic community within the US and Canada and to measure the consistency in mixture interpretation. The findings were that there was a large variation in analysts' interpretations between and within laboratories. Within this work, we sought to evaluate the same mock mixture cases analyzed in MIX13 but with a more current view of the state-of-the-science. Each of the five cases were analyzed using the Identifiler™ multiplex and interpreted with the combined probability of inclusion, CPI, and four different modern probabilistic genotyping systems. Cases 1–4 can be interpreted without difficulty by any of the four PG systems examined. Cases 1 and 4 could also be interpreted successfully with the CPI by assuming two donors. Cases 2 and 3 cannot be interpreted successfully with the CPI because of potential of allele dropout. Case 3 demonstrated the need to consider relevant background information before interpretation of the profile. This case does not show that there is some barrier to interpretation caused by relatedness beyond the increased allelic overlap that can occur. Had this profile been of better template it might have been interpreted using the CPI despite the (potential) relatedness of contributors. Case 5 suffers from over-engineering. It is unclear whether reference 5C, a non-donor, can be excluded by manual methods. Inclusion of reference 5C should be termed an adventitious match not a false inclusion. Beyond this statement this case does not contribute to the interlaboratory study of analyst/laboratory interpretation method performance, instead, it explores the limits of DNA analysis. Taken collectively the analysis of these five cases demonstrates the benefits of changing from CPI to a PG system. [ABSTRACT FROM AUTHOR]

This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[-ln(P)+a/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d = 3.87] along with the 95% uncertainty interval (Uk = 2 = 0.075 mmol/g) were determined for the reference isotherm using a Bayesian, Markov Chain Monte Carlo method. Together, this zeolitic reference material and the associated adsorption data provide a means for laboratories to test and validate high-pressure adsorption equipment and measurements. Recommendations are provided for measuring reliable high-pressure adsorption isotherms using this material, including activation procedures, data processing methods to determine surface excess uptake, and the appropriate equation of state to be used. [ABSTRACT FROM AUTHOR]