IMEP-40: Determintion of trace elements in seawater

Fifty-three participants from twenty-nine countries registered to the exercise. Seven participants did not report results. The test item used was a seawater sample containing the trace elements As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se and Zn. Laboratories with demonstrated experience in the field provided results to establish the assigned values (Xref). The standard uncertainties associated to the assigned values (uref) were calculated according to ISO Guide 35. Laboratory results were rated with z- and zeta (ζ-) scores in accordance with ISO 13528. The standard deviation for the proficiency assessment, , for all elements was based on the experience in the Water Framework Directive and was set at 25 %. The trace elements were present in very low concentration levels (low μg L-1 range equal to natural contamination levels) and therefore many laboratories reported "lower than" values. The percentage of satisfactory z-scores ranged from 41 % (Cr, Fe) to 86 % (Mo). The low concentration levels of the trace elements in a difficult matrix (high saline content) need to be taken into consideration to understand the general low rate of satisfactory scores. Laboratories that score systematically too high should examine the cause of this positive bias.JRC.D.5-Standards for Food Bioscienc

IMEP-42: Determination of PFASs in fish

The Institute for Reference Materials and Measurements of the Joint Research Centre, a Directorate General of the European Commission (EC-JRC-IRMM) operates the International Measurement Evaluation Programme (IMEP). It organises interlaboratory comparisons (ILC's) in support to European Union (EU) policies. This report presents the results of a proficiency test (PT), IMEP-42, on the determination of perfluoroalkyl substances (PFASs) in fish tissue. The exercise was organised in support to the Commission Recommendation 2010/161/EU on the monitoring of perfluoroalkylated substances in food and the Water Framework Directive 2000/60/EC. Seventeen participants from thirteen countries registered to the exercise and all of them reported results. The test item was fish tissue (pike-perch) containing perfluoroalkyl carboxylates as perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA) or perfluorotetradecanoic acid (PFTeDA); perfluoroalkyl sulfonates as perfluorohexanesulfonate (PFHxS), linear perfluorooctane sulfonate (L-PFOS) or branched perfluorooctane sulfonate (br-PFOS); and, perfluoroalkyl sulphonamides as perfluorooctane sulphonamide (FOSA). The test item was a candidate certified reference material (CRM) produced by IRMM under ISO Guide 34 accreditation and in line with ISO Guide 35. Laboratories with demonstrated experience in the field provided results to establish the assigned values (Xref). The standard uncertainties associated to the assigned values (uref) were calculated according to the ISO Guide 35 by combining the uncertainty of the characterisation (uchar) with a contribution for homogeneity (ubb) and for stability (ust). Laboratory results were rated with z- and zeta (ζ-) scores in accordance with ISO 13528. The standard deviation for the proficiency assessment, σ ̂, for all elements was set at 25 % of the respective assigned value. The overall performance in this PT was good even though analyte dependent. High rates (78% - 100%) of satisfactory performances expressed as z-scores ≤ 2 were obtained for L-PFOS, PFDA, PFUnDA, PFDoDA, tot-PFOS and FOSA while the lowest rates of satisfactory performances (50%) were obtained for br-PFOS and PFTrDA. Many "less than X" values were reported for the three PFASs that could not be scored due to the high uncertainty on the assigned value (PFNA, PFTeDA and PFHxS). The results in this PT showed that the sensitivities of the methods used by the participants were fit for the purpose of measuring the legal limits set in legislation.JRC.D.5-Standards for Food Bioscienc

IMEP-37: Determination of pesticides in grapes - Interlaboratory Comparison Report

This report presents the results of a proficiency test exercise (PT) which focussed on the determination of pesticides in grapes in support of Regulation 396/2005/EC of the European Parliament and of the Council on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Eighty-seven participants from thirty-three different countries registered to the exercise, of which eighty-one reported results. From these eighty-one participants, forty were from EU countries while forty-one were from outside the EU. The test item was a grapes sample spiked with 20 selected pesticides. The assigned values were obtained as the average of results reported by five expert laboratories having demonstrated experience in the analysis of pesticides in vegetable and fruit matrices. The standard uncertainties related to the assigned values (Uref) were calculated by combining the uncertainty of the characterisation (Uchar) with a contribution for homogeneity (Ubb) and for stability (Ust). Uchar was calculated following the ISO guide 35. Laboratory results were rated with z- and zeta (ζ-) scores in accordance with ISO 13528 and ISO 17043. The z-score compares the participant's deviation from the reference value with the standard deviation for proficiency assessment (σp) used as common quality criterion, the ζ-score states if the laboratory result agrees with the assigned value within the respective uncertainty. The standard deviation for the proficiency assessment, σp, was set by the advisory board of this PT at 25% for the 20 measured pesticides based on previous experience with similar measurands. Participants were not scored for triadimenol due to the large Uref associated to the assigned value. According to the results obtained in the frame of the IMEP-37 study, the participants performed satisfactorily for the 19 scored pesticides ranging from 81 % (carbendazim) to 97 % (azoxystrobin, penconazole, pyrimethanil) of satisfactory z-scores. When analysing the results of the group of non-EU countries separately, similar results were obtained. It can be concluded that the performance in this PT is satisfactory for the laboratories world-wide.JRC.D.5-Standards for Food Bioscienc

EURL-HM-22 Proficiency test report: Determination of total As, Cd, Pb, Hg, MeHg and inorganic As in fish

The European Union Reference Laboratory for Heavy Metals in Feed and Food (EURL-HM) organised a proficiency test (EURL-HM-22) for the determination of total As, Cd, Pb, Hg and inorganic As (iAs) in fish to support the Commission Regulation (EC) 1881/2006 setting maximum levels for certain contaminants in foodstuffs. This PT was open only to National Reference Laboratories (NRLs). The reference material "IAEA-436" (Tuna fish flesh homogenate) was used as test item. The finely ground dry powder material was rebottled, relabelled and dispatched to the participants. The reference values of interest were provided by the IAEA, together with an informative value for total Pb. The University of Graz (Austria) was requested to analyse the mass fraction of iAs in the material and reported a truncated value ("less than" 0.005 mg kg-1). Forty two participants from 30 countries registered to the exercise (all EU Member States plus Iceland and Norway). Only one participant could not report results due to technical instrumental problems. Laboratory results were rated using z- (z'- for MeHg) and zeta scores in accordance with ISO 13528:2015. The following relative standard deviations for proficiency assessment (σpt) were set according to the modified Horwitz equation: 13% for total Hg and MeHg; 15% for total As; and 22% for total Cd. No scoring was provided for total Pb and iAs. More than 92% of the participating NRLs reported satisfactory results (according to the z-score) for total As, Cd, Hg and MeHg, thus confirming their ability in monitoring the maximum levels set by the European Regulation (EC) No 1881/2006 for fish commodities. However, only 9 (out of 41) participants reported results for MeHg. Most of the laboratories provided realistic estimates of their measurement uncertainties.JRC.F.5-Food and Feed Complianc

Review of analytical methods for the determination of pesticide residues in grapes

This review paper presents an overview of analytical methods used for the analysis of pesticide residues in grapes and by-products in the last decade. The most widely used detection technique used for the determination of pesticides in grapes is mass spectrometry combined with gas and/or liquid chromatography. Multi-residue methods with selective sample treatment methodologies have been developed for this purpose. However, this review focuses not only on these common multi-residue methods but also on specific methodologies for the analysis of pesticides in grapes and by-products. Finally the limitations of multi-residue methods and future perspectives and trends for pesticide residue analysis in grapes are reviewed.JRC.D.5-Standards for Food Bioscienc

The integration of quality management systems in testing laboratories: a practitioner's report

When routine laboratories merge or are taken over by larger entities their quality management systems usually need to be integrated. In many laboratories, quality management systems according to ISO/IEC 17025 are in place. The integration of the quality management systems is often advantageous in terms of efficiency of operations, reduction in number of processes and consequently amount of quality documentation. However, a number of practical problems, some of them hard to overcome, may be encountered. Examples are how to deal with multi-site activities showing technical and/or cultural differences, how to merge historically different ways of working and how to overcome psychological resistance to change from laboratory staff. This paper demonstrates a way of working used in our organisation to integrate successfully the quality management systems of several laboratories under one quality management system. The laboratories were located in two different countries (Belgium and Italy) and had activities under ISO/IEC 17025, ISO/IEC 17043 and ISO Guide 34 accreditation. Involvement of the laboratory staff was essential for obtaining a fast and efficient integration.JRC.F.5-Food and Feed Complianc

Proficiency test on the determination of polyethylene and polybutylene terephthalate cyclic oligomers in a food simulant

A proficiency test (PT) was organised by the European Union Reference Laboratory for Food Contact Materials (EURL-FCM) to assess the analytical performance of National Reference Laboratories (NRL) and Official Control Laboratories (OCL) in the determination of mass fractions of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) cyclic dimers and trimers in official food simulant. Homogeneity, stability and the assigned values of the test items were evaluated by EURL-FCM based on an in-house validated HPLC-UV method. The standard operating procedure was provided to participants as an alternative method to be used. Laboratory results were rated using z and ζ scores according to ISO 13528:2015. The PT assessment standard deviation (σpt) was set for the four oligomers investigated to 20 % of the assigned values. A total of 36 participants from 26 countries registered and reported results. They received two test items: - a food simulant fortified with a known mass fraction of the four oligomers, and - a fortified food simulant D1 after a migration experiment of a PET bottle. Most of the participating laboratories reported satisfactory results with z scores ranging from 70 to 85 %. This PT, organised for the first time at EU level, shows that most of the NRLs and OCLs are able to monitor the investigated measurands.JRC.F.5-Food and Feed Complianc

State of the art in the determination of trace elements in seawater: a worldwide proficiency test

This manuscript presents the results of the International Measurement Evaluation Programme 40 (IMEP-40) study, a proficiency test (PT) which was organized to assess the world-wide performance of laboratories for the determination of trace elements in seawater. This PT supports the implementation of the European Union Water Framework Directive 2000/60/EC, which aims at achieving a long-term high level protection of the aquatic environment, covering lakes, ground water and coastal waters. Forty-six participants reported results. The test item was seawater containing the trace elements As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se and Zn. The trace elements in the test item were present in very low concentrations to mimic natural levels. The results of the participants were rated with z- and zeta (ζ-) scores in accordance with ISO 13528 and ISO 17043. The standard deviation for proficiency assessment, σ̂, was set at 25 % of the respective assigned values for the 12 measured elements based on previous experience with similar PTs. The low levels of the trace elements combined with the high salt concentration of the seawater made the measurements challenging. Many laboratories were unable to detect or quantify the elements and reported "lower than X" values. The percentage of satisfactory performances (expressed as z-scores) ranged from 41% (Cr, Fe) to 86% (Mo). The PT study showed that the use of proper standard methods, like ISO 17294-2, and sensitive techniques, like inductively coupled plasma mass spectrometry (ICP-MS), contributed to performing well in this PT round.JRC.D.5-Standards for Food Bioscienc

Determination of urea in pet feed: assessing the suitability of different analytical techniques using proficiency test data

The determination of urea in pet feed at contaminant levels using the spectrophotometric method described in Commission Regulation (EC) No 152/2009 has been reported by several EU laboratories to lack the required selectivity. Whilst urea is not authorised as an additive in pet feed, the control of urea in pet feed is of economic importance, because the addition of urea may unlawfully increase the apparent protein content. To investigate the capabilities of different analytical techniques, a proficiency test was organised where the participants (EU official control laboratories, laboratories from the academia and private laboratories) were free to use their method of choice for analysing three dog feed test materials, two samples of which were spiked with urea. Twenty-one laboratories submitted results using the following techniques: spectrophotometry (Implementing Regulation (EC) No 152/2009), LC-MS/MS, HPLC-UV, enzymatic-colorimetry, gravimetry and an ‘in-house photometric’ method. Only two laboratories that used LC-MS/MS were able to quantify urea accurately in the test material containing a mass fraction of 18.9 mg kg−1 whereas satisfactory results at the level of 258.9 mg kg−1 were obtained by one participant that used an ‘in-house photometric method’ and one that used the enzymatic method, in addition to the five participants using LC-MS/MS. The technique that provided the highest success rate across the three test materials was LC-MS/MS, whereas spectrophotometry, the enzymatic-based and HPLC-UV methods led to overestimated results in addition to a dispersion of results not suitable for compliance analysis. To address the determination of urea in pet feed at low levels, a better performing method than the one described in the legislation is required.</p