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Purpose: A simple single-unit activity monitor (Activ8), which is based on a tri-axial accelerometer, measures specific body postures and movements, and has potential for research and clinical practice to monitor and optimize physical behavior of people with chronic conditions. However, the validity of the Activ8 in people with lower-limb amputation is unknown. Studying validity in this specific group is needed because they often have postures and movements that differ from the normal population, and which might affect validity. Therefore our study aimed to validate the Activ8 to measure body postures and movements in people with a lower-limb amputation. Methods: Thirty people with a unilateral lower-limb amputation and who are able to walk with a prosthesis completed two activity protocols in a simulated home setting: one with basic activities (only one posture or movement) and one with functional activities from daily living. Outcomes of the Activ8 (used in thigh-fixed position and pocket position) were compared to outcomes of video observation (the reference method). Primary analyses focused on the agreement in duration of merged measures of physical activity (walking, running, cycling, standing) and sedentary behavior (lying/sitting) with the Activ8 used in thigh-fixed position. Additional analyses included the detection of specific types of physical activity, the effects of amputation level and cause, and the validity of the Activ8 in pocket position. Results: Overall percentage time differences between Activ8 (thigh-fixed position) and video observation for merged measures of physical activity and sedentary behavior outcomes were -2.7% and 2.3%, respectively. These percentages were -1.6% and 1.3% for the basic protocol, and -3.9% and 3.6% for the functional protocol, respectively. For specific postures and movements, differences were larger (ranging from -12.6% to 7.1%). Conclusion: The Activ8 activity monitor has acceptable validity to measure physical activity and sedentary behavior in people with a unilateral lower-limb amputation. [ABSTRACT FROM AUTHOR]

The existing Air Quality Directive 2008/50/EC establishes within the European Union (EU) member states limit values for fine air particulate matter (PM2.5) including the possibility to discount natural sources of pollution when assessing compliance with the legislation. In proving this, EU member states shall determine, amongst others, the rural background concentration of some anions (Cl−, NO3− and SO42−) and cations (Na+, NH4+, K+, Ca2+ and Mg2+). To deliver reliable data and to comply with the data quality objectives of the legislation, environmental control laboratories should use certified reference materials (CRMs) to validate or verify the performance of their analytical methods. Since no CRMs for anions and cations in PM2.5 are presently available, we present the commutability issues encountered during the first attempt to develop such a material. We demonstrate that a dust, collected in a road tunnel and previously used for the production of two CRMs of a PM10-like material, does not behave as an authentic fine particulate matter collected according to EN12341:2014 when measured by an established method proposed by the European Committee for Standardization (CEN/TR 16269:2011). The water-soluble fractions of SO42−, NH4+, K+, Ca2+ and Mg2+ in a PM2.5-like candidate CRM produced from that road tunnel dust are only fully extracted after 3 h of sonication and not after 30 min, as stated in the method. Moreover, we found that the particle size of the test material influenced the extraction yield of K+, Ca2+ and Mg2+, suggesting that these ionic species were incorporated in the core of the particles and inaccessible to the extraction procedure. These particular features make the material unsuitable for the measurements of ions with the CEN method. The difference in the extraction time can be seen as a commutability issue and the candidate CRM should be considered as not commutable with routine samples. This demonstrates that commutability studies should not only be considered for clinical CRMs, but also for inorganic CRMs when they are intended to be used to quantify operationally defined analytes. [ABSTRACT FROM AUTHOR]

Study design:Cross-sectional.Objectives:To determine the prevalence and severity of fatigue in persons with subacute spinal cord injury (SCI), assess whether demographic and lesion characteristics are related to fatigue and determine the relationship with physical fitness and physical behavior.Setting:Measurements were performed 2 months before discharge from inpatient rehabilitation.Methods:Thirty-six persons with subacute SCI, dependent on a manual wheelchair, mean age 43±15 and 83% men, completed the Fatigue Severity Scale (FSS). FSS scores >4 indicated fatigue. We recorded age and lesion characteristics, measured body mass index, measured peak power output and peak oxygen uptake during a maximal handcycling test and determined physical behavior using an accelerometer-based activity monitor. T-tests were used to test for differences in fatigue between subgroups based on age and lesion characteristics, and regression analyses to assess the relationship with physical fitness and physical behavior.Results:Mean FSS was 3.3±1.3. Fatigue, including severe fatigue, was prevalent in 31% (95% confidence interval: 16-46) of participants compared with 18% in the general population. Furthermore, mean fatigue was significantly higher in persons with incomplete compared with complete lesions (t=2.22, P=0.03). Mean scores between other subgroups did not differ significantly. Of the physical fitness and physical behavior measures, only peak oxygen uptake tended to be related to more fatigue (B=−1.47, P=0.05).Conclusion:Fatigue was prevalent and is of concern in persons with subacute SCI. Those with incomplete lesions seem to be at higher risk. Because fatigue is known to persist among persons with SCI, interventions to reduce fatigue seem necessary. [ABSTRACT FROM AUTHOR]

Inconsistent quantification results obtained from various analytical methods for food allergen testing hamper an accurate quantitative risk assessment and its regulatory implementation. In order to overcome such problems, a concept aiming at ensuring the comparability of quantitative food allergen measurement results is presented here. It is based on an approach called reference measurement system for food allergens, which uses a commonly agreed reference, namely the 'mass fraction of total protein of the allergenic ingredient in food'. The necessary system components are outlined, consisting of a primary reference measurement method, a certified reference material and a reference laboratory. This metrology-based concept can be applied to quantify various food allergens determined with different analytical procedures. The example of 'milk in cookies' is used to demonstrate the approach., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: eHealth interventions can improve the health outcomes of people with a low socioeconomic position (SEP) by promoting healthy lifestyle behaviours. However, developing and implementing these interventions among the target group can be challenging for professionals. To facilitate the uptake of effective interventions, this study aimed to identify the barriers and facilitators anticipated or experienced by professionals in the development, reach, adherence, implementation and evaluation phases of eHealth interventions for people with a low SEP., Method: We used a Delphi method, consisting of two online questionnaires, to determine the consensus on barriers and facilitators anticipated or experienced during eHealth intervention phases and their importance. Participants provided open-ended responses in the first round and rated statements in the second round. The interquartile range was used to calculate consensus, and the (totally) agree ratings were used to assess importance., Results: Twenty-seven professionals participated in the first round, and 19 (70.4%) completed the second round. We found a consensus for 34.8% of the 46 items related to highly important rated barriers, such as the lack of involvement of low-SEP people in the development phase, lack of knowledge among professionals about reaching the target group, and lack of knowledge among lower-SEP groups about using eHealth interventions. Additionally, we identified a consensus for 80% of the 60 items related to highly important rated facilitators, such as rewarding people with a low SEP for their involvement in the development phase and connecting eHealth interventions to the everyday lives of lower-SEP groups to enhance reach., Conclusion: Our study provides valuable insights into the barriers and facilitators of developing eHealth interventions for people with a low SEP by examining current practices and offering recommendations for future improvements. Strengthening facilitators can help overcome these barriers. To achieve this, we recommend defining the roles of professionals and lower-SEP groups in each phase of eHealth intervention and disseminating this study's findings to professionals to optimize the impact of eHealth interventions for this group., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: To assess the cost-effectiveness of a cardiac rehabilitation (CR) program specifically designed for cardiac patients with obesity vs standard CR., Design: Cost-effectiveness analysis based on observations in a randomized controlled trial., Setting: Three regional CR centers in the Netherlands., Participants: Cardiac patients (N=201) with obesity (BMI≥30 kg/m 2 ) referred to CR., Interventions: Participants were randomized to a CR program specifically designed for patients with obesity (OPTICARE XL; N=102) or standard CR. OPTICARE XL included aerobic and strength exercise and behavioral coaching on diet and physical activity during 12 weeks, followed by a 9-month after-care program with "booster" educational sessions. Standard CR consisted of a 6- to 12-week aerobic exercise program, supplemented with cardiovascular lifestyle education., Main Outcome Measures: An economic evaluation, with an 18-month time horizon, in terms of quality-adjusted life years (QALYs) and costs from the societal perspective was performed. Costs were reported in 2020 Euros, discounted at a 4% annual rate, and health effects were discounted at a 1.5% annual rate., Results: OPTICARE XL CR and standard CR resulted in comparable health gain per patient (0.958 vs 0.965 QALYs, respectively; P=.96). Overall, OPTICARE XL CR saved costs (-€4542) compared with the standard CR group. The direct costs for OPTICARE XL CR were higher than for standard CR (€10,712 vs €9951), whereas indirect costs were lower (€51,789 vs €57,092), but these differences were not significant., Conclusions: This economic evaluation showed no differences between OPTICARE XL CR and standard CR in health effects and costs in cardiac patients with obesity., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The authorisation of genetically modified food and feed in the EU is subject to the provision of evidence of safety and of the availability of reliable analytical methods. These methods represent an essential tool for official laboratories to enforce a harmonised market control. Here the validation of droplet digital PCR (dPCR) methods has been performed for studying if the performance and acceptance parameters set by EU and other international guidelines for the analysis of genetically modified organisms (GMO) in food and feed are suitable and achievable also with such methods. The single-laboratory validation study showed that performance requirements set for GMO analysis by real time PCR can also be used to assess dPCR-based methods. Moreover, trueness and precision were assessed for both simplex and duplex formats in a multi-laboratory validation study organised according to international standards. Overall, the data on trueness, repeatability and reproducibility precision resulting from the collaborative study are satisfying the acceptance criteria for the respective parameters as stipulated in the EU and other international guidance such as the Codex Committee on Methods of Analysis and Sampling (CCMAS). For instance, the duplex droplet dPCR method for MON810 showed relative repeatability standard deviations from 1.8% to 15.7%, while the relative reproducibility standard deviation was found to be between 2.1% and 16.5% over the dynamic range studied. Moreover, the relative bias of the dPCR methods was well below 25% across the entire dynamic range. In addition, other aspects supporting the application of digital PCR for the control of GMOs on the market were experimentally assessed such as the conversion of the measurement results from copy number ratio to mass fraction, the influence of the DNA extraction step and of the ingredient content. It was found that the DNA extraction step added only a limited contribution to the variability of the measurement results under the studied conditions. The decreasing amount of the target ingredient content may decrease the level of precision of the method, although within the acceptance range of GMO performance parameters., Competing Interests: o This manuscript has not been submitted to, nor is under review at, another journal or other publishing venue. o The authors have no affiliation with any organization with a direct or indirect financial interest in the subject matter discussed in the manuscript., (© 2022 The Authors.)

Nowadays the quantification of the content of genetically modified (GM) constituents in food or feed products is performed by using either quantitative real-time PCR (qPCR) or digital PCR (dPCR). The latter is increasingly used. Therefore, experimental protocols for the quantification of 52 GM events authorised in the EU have been converted into a digital format and minimum performance characteristics for dPCR methods are detailed. Because of the need to harmonise the transformation of PCR results between two different measurement scales, 50 conversion factors for Certified Reference Materials (CF CRM ) have been experimentally determined by three and sometimes four independent expert laboratories. The uncertainty of each CF CRM has been estimated to express dPCR results in mass fraction with a consistent uncertainty contribution. In 38 out of 58 cases, the validated qPCR methods (for 52 event-specific and 6 taxon-specific measurements) could easily be transferred into dPCR methods by using the same oligo sequences, final oligo concentration or annealing temperatures for the dPCR procedure. Laboratories have nevertheless used different strategies to improve the resolution or to reduce the so-called rain in their dPCR outcome. Those modifications were needed for PCR procedures that could not be converted without changes into a digital format. Therefore, exclusion/quality criteria such as the maximum rate of partitions with intermediate fluorescence "rain", the minimum resolution and repeatability are suggested for dPCR methods. The CF CRM determined in this study were generally in agreement with the declared zygosity of the GM parental donor for hemizygous maize events. In a limited number of GM events the CF CRM values were significantly different when measured with different maize-specific ( ZmAdh1 or hmgA ) genes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)

Background: Alternaria toxins are ubiquitous contaminants in highly consumed food products. Therefore, they are candidates to be regulated by EU legislation. In this context, the availability of reliable analytical methods is a keystone both for protecting the health of citizens and smooth functioning of the European market., Objective: This paper describes an advanced LC-MS/MS method based on isotope dilution quantification suitable for the determination of altenuene, alternariol, alternariol monomethyl ether, tenuazonic acid, and tentoxin in tomato puree, wheat, and sunflower seeds., Methods: The method has been validated in an interlaboratory study that included the analysis of both spiked and naturally contaminated food commodities. Twenty-three participants contributed with analytical data., Results: The average recoveries and relative standard deviations for repeatability and reproducibility obtained across the tested matrixes were: 97, 8.0, and 23%, for altenuene, respectively; 95, 9.2, and 17% for alternariol, respectively; 98, 6.4, and 13% for alternariol monomethyl ether, respectively; 97, 4.2, and 9.3% for tenuazonic acid, respectively; and 102, 5.6, and 15% for tentoxin, respectively. The method enabled the determination of all tested Alternaria toxins close to or below 1 µg/kg., Conclusion: Overall, the method showed a satisfactory trueness and precision, complying with the requirements for the monitoring of mycotoxins in food in the EU. It is currently under evaluation by the European Committee for Standardization for adoption as a standard method., Highlights: Isotope dilution mass spectrometry method for the determination of Alternaria toxins in food., (© AOAC INTERNATIONAL 2021.)

A HPLC-UV/FLD method was validated for the quantification of six polyethylene terephthalate (PET) and four polybutylene terephthalate (PBT) oligomers. PBT oligomers are EU regulated, while the PET ones are considered non-intentionally added substances (NIAS). LOQs were higher than 0.4 and 3.5 μg kg -1 for the simulants and in the polymer extracts, respectively. Recoveries ranged from 95 to 114 % with RSDs below 12%. Migration testing of PBT and polypropylene coffee capsules were performed with H 2 O and simulant C, and extracts were obtained with accelerated solvent extraction (ASE). For the latter legislative limits weren't surpassed. As no migration limits are existing for the analytes, both EFSA's toxicological threshold of concern (TTC) and sum of oligomers approaches were applied. The majority of oligomers were below the TTC (90 µg/person/day), but the limit value of 50 µg/kg food was surpassed for some capsules, which indicates a significant intake in both single and multiple consumption., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In 2000, the Water Framework Directive (WFD) came into force in the European Union with the aim of protecting and improving water quality. The priority substances established to be monitored are predominantly organic compounds, for which the WFD sets the requirement of 'whole water sample' analysis. This legislative requirement poses analytical challenges for the monitoring laboratories as well as technical challenges for reference materials producers. In the past, there were attempts to produce reference materials as quality assurance/quality control tools for measuring organic priority substances in whole water. A critical reflection on the approaches and solutions applied to prepare such kind of matrix reference materials is presented along with a discussion on the difficulties encountered by the analytical laboratories in analysing such complex matrices. The Certified Reference Material (CRM) ERM-CA100 can be considered as a pioneer for a 'whole water' CRM (containing humic acids) and has been designed for the analysis of polycyclic aromatic hydrocarbons (PAHs). Further developments seem to be necessary to upgrade the design towards a CRM which will also include suspended particulate matter, another basic constituent of natural surface water samples.

The establishment of a reference method for the determination of the allergen protein content in a processed food material has been explored. An analytical approach was developed to enable the comparability of food allergen measurement results expressed in a decision-relevant manner. A proof of concept is here presented, resulting in quantity values for the common measurand, namely 'mass of total allergen protein per mass of food'. The quantities are determined with SI traceability to enable the comparability of reported results. A method for the quantification of total milk protein content in an incurred baked food at a concentration level clinically relevant is presented. The strategy on how to obtain the final analytical result is outlined. Challenges associated with this method are discussed, in particular the optimal extraction of the marker proteins, the complete digestion and release of the peptides in an equimolar fashion, the use of conversion factors to translate the amount of measured proteins into total milk protein and the estimation of the uncertainty contributions as well as of the combined uncertainty of the final result. The implementation of such a reference method for the determination of the total allergen content in a processed food is an important step, which will provide comparable measurement data of relevance to risk assessors. Graphical abstract.

Introduction: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aβ)1-42 (Aβ 42 ). They are intended to be used to calibrate diagnostic assays for Aβ 42 ., Methods: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays., Results: The certified Aβ 42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22 μg/L, respectively, with expanded uncertainties (k = 2) of 0.07, 0.11, and 0.18 μg/L, respectively. Before re-calibration, a good correlation (Pearson's r > 0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to < 5%., Discussion: The Aβ 42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aβ 42 ., (© 2020 European Commission - Joint Research Centre. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Chemical substances shall not migrate from food contact materials (FCM) at levels that are potentially harmful for the consumers. Each of the current analytical methods applied to verify the migration of substances from FCM covers only one or few substances. There is a very limited number of publications on the development of analytical methods allowing the simultaneous determination of several classes of FCM substances, and almost none of them reported methods entirely dedicated to the ones in the positive list of Commission Regulation (EU) No. 10/2011 for plastic FCMs. Therefore, a simple, sensitive and reliable multi-analyte method was developed for the analysis of FCM substances in food simulants. It employs an optimised liquid-liquid extraction with dichloromethane as extraction solvent in the presence of 10% m/v NaCl, followed by quantitative analysis with gas chromatography coupled to mass spectrometry (GC-MS). A combination of total ion chromatograms (TICs) and extracted ion chromatograms (EICs) was used. The optimisation and validation of the method have been carried out according to current international guidelines. Adequate sensitivity was demonstrated in the selected concentration ranges for most of the analytes, with limits of quantification (LOQs) at least three times lower than the legislative limit, when existing. The results showed that the method is sufficiently accurate for the majority of substances, with recoveries between 70 and 115% and relative standard deviations (RSDs) smaller than 20% at three concentration levels. The method was applied to the analysis of some FCM multilayers. The method allows, for the first time, the simultaneous quantification of 84 FCM substances in two of the official food simulants (A and C) at levels of a few ng g -1 . Graphical abstract.

National Reference Laboratories (NRLs) in the Member States of the European Union (EU) monitor the implementation of the EU legislation on the presence of genetically modified organisms (GMOs) in food and feed. The EU Reference Laboratory for GM Food and Feed (EURL GMFF) supports the harmonisation of measurement procedures and the improvement of the analytical performance of these laboratories, among others through the organisation of a proficiency testing (PT) scheme. The PT results reported over 10 years have been analysed using common criteria applied to the reported data. The outcome revealed a gradual decrease of the relative standard deviation within the sets of the reported data with time. The extent of the deviation of the results from the assigned value also diminished between 2010 and 2019. The average deviation from the assigned value was independent of the GM content in the later PT rounds but it was affected by the complexity of the test item matrix. Performance scores were calculated for all results reported by the 62 NRLs. The number of unsatisfactory performance scores obtained decreased with time. The trends observed indicate an improvement in the analytical performance and an increased harmonisation of GMO testing within the EU enforcement laboratories., Competing Interests: The authors declare that they have no conflict of interests., (© 2020 The Authors.)

The outcome of proficiency tests (PTs) is influenced, among others, by the evaluation procedure chosen by the PT provider. In particular for PTs on GMO testing a log-data transformation is often applied to fit skewed data distributions into a normal distribution. The study presented here has challenged this commonly applied approach. The 56 data populations from proficiency testing rounds organised since 2010 by the European Union Reference Laboratory for Genetically Modified Food and Feed (EURL GMFF) were used to investigate the assumption of a normal distribution of reported results within a PT. Statistical evaluation of the data distributions, composed of 3178 reported results, revealed that 41 of the 56 datasets showed indeed a normal distribution. For 10 datasets, the deviation from normality was not statistically significant at the raw or log scale, indicating that the normality assumption cannot be rejected. The normality of the five remaining datasets was statistically significant after log-data transformation. These datasets, however, appeared to be multimodal as a result of technical/experimental issues with the applied methods. On the basis of the real datasets analysed herein, it is concluded that the log transformation of reported data in proficiency testing rounds is often not necessary and should be cautiously applied. It is further shown that the log-data transformation, when applied to PT results, favours the positive performance scoring for overestimated results and strongly penalises underestimated results. The evaluation of the participants' performance without prior transformation of their results may highlight rather than hide relevant underlying analytical problems and is recommended as an outcome of this study. Graphical abstract.

The unintentional presence of even trace amounts of certain foods constitutes a major hazard for those who suffer from food allergies. For many food industries, product and raw ingredient surveillance forms part of their risk assessment procedures. This may require the detection of multiple allergens in a wide variety of matrices. Mass spectrometry offers a possible solution for the quantification of multiple allergens in a single analysis. The capability of MS to quantify many peptides from a complex protein digestion is well known. However, a lack of matrix certified reference materials has made the optimisation of extraction and digestion conditions for multiplexed allergen quantification difficult to assess. Here, we report a systematic study, using preliminary screening followed by a Design of Experiments approach, to find the optimal buffer and digestion conditions for detecting milk and egg protein markers in a model processed food matrix. Five of the most commonly used buffers, two chaotropic reagents and two reducing reagents were assessed for the optimal extraction of multiple protein markers. While the choice of background buffer had little impact, the use of chaotropic and reducing reagents showed significant benefits for the extraction of most proteins. A full factorial design experiment was applied to the parameters shown to have a significant impact on protein recovery. These studies suggest that a single optimal set of extraction conditions enabling the quantitative recovery of all proteins is not easily achieved. Therefore, although MS is capable of the simultaneous quantification of many peptides in a single run, greater consideration of protein extraction is required before these are applied for multiplex allergen quantification in food matrices. Graphical abstract.

A proficiency testing (PT) round dedicated to assess the competence of European Union (EU) National Reference Laboratories (NRLs), EU Official Control Laboratories (OCLs) and OCLs from associated countries for the determination of the insecticide fipronil in eggs is described. The content of the target analytes (sum of fipronil plus its metabolite fipronil sulfone, expressed as fipronil in the PT test material) was set around the regulated Maximum Residue Level (MRL) set by EU legislation. The PT was organised by the European Commission's (EC) Directorate General (DG) Joint Research Centre (JRC) - in agreement with the EC DG for Health and Food Safety (SANTE) - following a request by the Belgian Authorities. Eighty-six NRLs and OCLs from 22 EU Member States, Norway, Serbia and Albania participated. The test items used were two materials made of frozen liquid eggs, processed and characterised at the JRC facilities in Geel (Belgium). The majority of the participants (94%) were shown to have a satisfactory performance, expressed as z scores, thus demonstrating the analytical capability of most of the participating NRLs and OCLs to enforce the relevant EU Regulations ((EC) 396/2005 and 1127/2014). Furthermore, 93% of the participants who provided a compliance statement classified, correctly, one of the test items as non-compliant.

The use of polybutylene terephthalate (PBT) as a food contact material is increasing over the last years. Typical contaminations in the final PBT product include its cyclic oligomers, which are allowed as additives in food contact plastics according to Regulation (EU) No. 10/2011. Their investigation is currently limited by the lack of analytical standards and physical-chemical information. Therefore, four PBT cyclic oligomers have been isolated and purified from a PBT raw material with an automated preparative HPLC-DAD system. Comprehensive characterization of the compounds was performed using Ultra-High Performance Liquid Chromatography (UHPLC) with high resolution time-of-flight mass spectrometry, Fourier-Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Nuclear Magnetic Resonance (NMR) spectroscopy. The purity of each oligomer was assessed using a ¹H qNMR method and ranged from 96.1% to 97.0% for PBT tetramer and trimer respectively. The availability of pure and well characterized PBT cyclic oligomer standards will facilitate future studies of release from plastic food packaging materials.

The GM content in a food or feed product produced from or containing genetically modified organisms (GMO) has to be expressed in Europe in the form of a GM mass fraction. However, the most widely used quantification methods, based on PCR, are basically counting PCR-amplifiable DNA fragments in a sample extract. This paper outlines the requirements for obtaining comparable measurement results which are fit for regulatory decision-making. It introduces the concept of a reference measurement system which enables GMO analysis laboratories to relate their results to a universally accessible reference, thus establishing metrological traceability to a unique reference point. The conversion factors required for transforming data from one measurement unit into the other have to carry a minimum uncertainty and are anchored to specified certified reference materials. The establishment of such conversion factors and related calibration approaches to achieve comparable GM quantification results are sketched. Graphical abstract ᅟ.

Knowledge of the number of DNA sequences targeted by the taxon-specific reference assays is essential for correct GM quantification and is key to the harmonisation of measurement results. In the present study droplet digital PCR (ddPCR) was used to determine the number of DNA target copies of taxon-specific assays validated for real-time PCR for the four main genetically modified (GM) crops. The transferability of experimental conditions from real-time PCR to ddPCR was also explored, as well as the effect of DNA digestion. The results of this study indicate that for each crop at least one taxon-specific assay can be identified as having a single DNA target. A short list of taxon-specific reference assays is proposed as best candidates for the relative quantification of GM events for soybean, maize, cotton and oilseed rape. The investigated assays could be in most cases transferred to ddPCR without further optimisation. The use of DNA digestion did not improve ddPCR characteristics such as rain and resolution at the conditions tested.

An HPLC method with fluorescence detection has been developed and validated for the quantification of six fluorescent whitening agents (FWA) in plastic beverage cups after extraction and in food simulants after migration at 70°C for 2 h. The sensitivity of the method was high with LODs ranging from 0.053 to 0.251 μg kg -1 and LOQs from 0.107 to 0.504 μg kg -1 . Accuracy and precision were highly acceptable, with recoveries greater than 82% and RSDs (%) below 16%. The expanded combined uncertainty was found to be less than 23% for the measurements of all studied FWAs. In extracting the analytes from food contact materials (FCM), accelerated solvent extraction (ASE) and Soxhlet extraction were applied using ethanol as the extraction solvent. The results obtained for FWA in 10 different food plastic cups, made from different polymers, were compared. The ASE technique proved to be faster, more effective and efficient than Soxhlet extraction. Migration tests with official food simulants from Regulation (EU) No 10/2011 showed that the substances studied could potentially migrate using the selected migration conditions. The most pronounced effect was observed in case of simulant D1 (50% w/v ethanol in water). The analytical method proved to be a simple, fast, sensitive and reliable tool for the simultaneous quantification of six of the most used FWAs in both FCM extracts and food simulants after migration experiments.