1
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Jacob O, Stefaniak EA, Seghers J, La Spina R, Schirinzi GF, Chatzipanagis K, Held A, Emteborg H, Koeber R, Elsner M, Ivleva NP. Towards a reference material for microplastics' number concentration-case study of PET in water using Raman microspectroscopy. Anal Bioanal Chem 2024; 416:3045-3058. [PMID: 38546794 PMCID: PMC11045626 DOI: 10.1007/s00216-024-05251-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 04/28/2024]
Abstract
Increasing demand for size-resolved identification and quantification of microplastic particles in drinking water and environmental samples requires the adequate validation of methods and techniques that can be used for this purpose. In turn, the feasibility of such validation depends on the existence of suitable certified reference materials (CRM). A new candidate reference material (RM), consisting of polyethylene terephthalate (PET) particles and a water matrix, has been developed. Here, we examine its suitability with respect to a homogeneous and stable microplastic particle number concentration across its individual units. A measurement series employing tailor-made software for automated counting and analysis of particles (TUM-ParticleTyper 2) coupled with Raman microspectroscopy showed evidence of the candidate RM homogeneity with a relative standard deviation of 12% of PET particle counts involving particle sizes >30 µm. Both the total particle count and the respective sums within distinct size classes were comparable in all selected candidate RM units. We demonstrate the feasibility of production of a reference material that is sufficiently homogeneous and stable with respect to the particle number concentration.
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Affiliation(s)
- Oliver Jacob
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | | | - John Seghers
- Joint Research Centre (JRC), European Commission (EC), Geel, Belgium
| | - Rita La Spina
- Joint Research Centre (JRC), European Commission (EC), Geel, Belgium
| | | | | | - Andrea Held
- Joint Research Centre (JRC), European Commission (EC), Geel, Belgium
| | - Håkan Emteborg
- Joint Research Centre (JRC), European Commission (EC), Geel, Belgium
| | - Robert Koeber
- Joint Research Centre (JRC), European Commission (EC), Geel, Belgium
| | - Martin Elsner
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Natalia P Ivleva
- Institute of Water Chemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany.
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2
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Emteborg H, Seghers J, García-Ruiz S, Elordui-Zapatarietxe S, Breidbach A, Labibes K, Charoud-Got J, Koeber R. Paving the way for new and challenging matrix reference materials-particle suspensions at the core of material processing providing RMs for method development and method validation. Anal Bioanal Chem 2024; 416:2079-2088. [PMID: 37987767 PMCID: PMC10950969 DOI: 10.1007/s00216-023-05046-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/03/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023]
Abstract
Sufficient homogeneity of the certified parameter(s) over the whole fill series of a matrix reference material (RM) is a fundamental quality criterion. In practice, the heterogeneity of the target parameter is evaluated, whereby a relative value can be calculated of how much the target parameter is varying over the RM-batch. A high degree of homogeneity (low heterogeneity) is an inherent quality mark of a good RM. Here, we report how challenging matrix RMs were produced by using particle suspensions at the core of the material processing step. The examples of matrix RMs produced span from whole water reference materials for persistent organic pollutants, PM2.5-like atmospheric dust certified for specific ions to microplastic RMs. Most of these RMs were subsequently used in different phases of analytical method development or for method validation. Common to all these matrices is that they cannot be easily mixed, handled, or dosed to prepare larger sample batches. In all cases, a continuously stirred suspension of particles was used during material processing. In general, relative between-bottle heterogeneities from 1.6 to 6% were achieved for the target parameters in these matrix presentations. Concerning developments of new CRMs in emerging fields, the co-dependence between the availability of validated analytical methods with good repeatability and testing materials with a known and high homogeneity of the target parameter(s) becomes particularly challenging. This situation is an RM/Method causality dilemma. To overcome that hurdle, strategies are proposed for stepwise processes where RM producers and a network of analytical method developers could work hand in hand. In addition, development of a portfolio of inexpensive and well-homogenised common samples coupled with a reporting interface is suggested. This would benefit method developers and RM producers alike. As more and more data is compiled for a specific matrix, it paves the way for new and challenging RMs that can later be used by a wider community.
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Affiliation(s)
- Håkan Emteborg
- European Commission, Joint Research Centre (JRC), Geel, Belgium.
| | - John Seghers
- European Commission, Joint Research Centre (JRC), Geel, Belgium
| | | | | | | | | | | | - Robert Koeber
- European Commission, Joint Research Centre (JRC), Geel, Belgium
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3
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Gonçalves C, Bouten K, Dehouck P, Emteborg H, Stroka J, Vincent U, von Holst C. Determination of urea in pet feed: assessing the suitability of different analytical techniques using proficiency test data. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2024; 41:249-260. [PMID: 38324728 DOI: 10.1080/19440049.2023.2300741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/27/2023] [Indexed: 02/09/2024]
Abstract
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.
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Affiliation(s)
| | - Katrien Bouten
- Joint Research Centre (JRC), European Commission, Geel, Belgium
| | - Pieter Dehouck
- Joint Research Centre (JRC), European Commission, Geel, Belgium
| | - Håkan Emteborg
- Joint Research Centre (JRC), European Commission, Geel, Belgium
| | - Joerg Stroka
- Joint Research Centre (JRC), European Commission, Geel, Belgium
| | - Ursula Vincent
- Joint Research Centre (JRC), European Commission, Geel, Belgium
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4
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Ellisor DL, Bayless AL, Schock TB, Davis WC, Knott BT, Seghers J, Leys H, Emteborg H. Multi-omics characterization of NIST seafood reference materials and alternative matrix preparations. Anal Bioanal Chem 2024; 416:773-785. [PMID: 37723254 DOI: 10.1007/s00216-023-04928-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/25/2023] [Accepted: 08/29/2023] [Indexed: 09/20/2023]
Abstract
The National Institute of Standards and Technology (NIST) has prepared four seafood reference materials (RMs) for use in food safety and nutrition studies: wild-caught and aquacultured salmon (RM 8256 and RM 8257) and wild-caught and aquacultured shrimp (RM 8258 and RM 8259). These materials were characterized using genetic, metabolomic (1H-NMR, nuclear magnetic resonance and LC-HRMS/MS, liquid chromatography high-resolution tandem mass spectrometry), lipidomic, and proteomic methods to explore their use as matrix-matched, multi-omic differential materials for method development towards identifying product source and/or as quality control in untargeted omics studies. The results from experimental replicates were reproducible for each reference material and analytical method, with the most abundant features reported. Additionally, differences between the materials could be detected, where wild-caught and aquacultured seafood could be distinguished using untargeted metabolite, lipid, and protein analyses. Further processing of the fresh-frozen RMs by freeze-drying revealed the freeze-dried seafoods could still be reliably discerned. These results demonstrate the usefulness of these reference materials as tools for omics instrument validation and measurement harmonization in seafood-related studies. Furthermore, their use as differential quality control (QC) materials, regardless of preparation method, may also provide a tool for laboratories to demonstrate proficiency at discriminating between products based on source/species.
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Affiliation(s)
- Debra L Ellisor
- National Institute of Standards and Technology Materials Measurement Laboratory, Charleston, SC, USA.
| | - Amanda L Bayless
- National Institute of Standards and Technology Materials Measurement Laboratory, Charleston, SC, USA
| | - Tracey B Schock
- National Institute of Standards and Technology Materials Measurement Laboratory, Charleston, SC, USA
| | - W Clay Davis
- National Institute of Standards and Technology Materials Measurement Laboratory, Charleston, SC, USA
| | - B Trey Knott
- National Oceanic and Atmospheric Administration Northwest Fisheries Science Center Forensic Laboratory, Charleston, SC, USA
| | - John Seghers
- European Commission - Joint Research Centre, Directorate Health and Food, Geel, Belgium
| | - Hanne Leys
- European Commission - Joint Research Centre, Directorate Health and Food, Geel, Belgium
| | - Håkan Emteborg
- European Commission - Joint Research Centre, Directorate Health and Food, Geel, Belgium
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5
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Seghers J, Günther M, Breidbach A, Peez N, Imhof W, Emteborg H. Feasibility of using quantitative 1H-NMR spectroscopy and ultra-microbalances for investigation of a PET microplastic reference material. Anal Bioanal Chem 2023:10.1007/s00216-023-04567-0. [PMID: 36750474 DOI: 10.1007/s00216-023-04567-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/09/2023]
Abstract
Here, we report on the feasibility of using quantitative NMR and ultra-microbalances for additional measurements of the mass of poly-ethylene terephthalate (PET) particles in a reference material (RM). The microplastic (MP) PET particles were immobilised in solid NaCl following freeze-drying of a 1-ml NaCl suspension. The particles ranged from 30 to about 200 µm (Feretmin). In a 3-day process, more than 500 such units of PET particles in the NaCl carrier were prepared and later used in a large-scale inter-laboratory comparison. The homogeneity of PET in the salt carrier over these 500 units had previously been evaluated with respect to the mass of PET using an ultra-microbalance. In addition to the original results obtained by weighing, two independent results of quantitative 1H-NMR have been obtained for further investigation of this reference material together with one additional set of weighing data. The NMR data were used for confirmation of the weighed amount of PET (as weighing is non-specific for PET). Average masses of 0.293 ± 0.04 mg and 0.286 ± 0.03 mg of PET were obtained using two different ultra-microbalances (14% RSD for n = 14 and 9% RSD for n = 4, respectively). The corresponding 1H-NMR data was 0.300 ± 0.02 mg of PET (6.7% RSD for n = 5) and 0.345 ± 0.04 mg of PET (12.5% RSD for n = 14), respectively. The average mass of PET obtained by 1H-NMR measurements was in agreement with the weighed amounts within their standard deviations. A mean value of 0.306 mg PET with an expanded uncertainty of 0.058 mg (± 19% relative) was calculated, and it is traceable to the SI system of measurements. Measurement of PET by quantitative 1H-NMR spectroscopy is also reported for a water sample. The PET contained in one RM sample was transferred to 1 L of water to mimic a drinking water sample for microplastics.
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Affiliation(s)
- John Seghers
- Joint Research Centre (JRC), European Commission, Geel, Belgium
| | | | | | | | | | - Håkan Emteborg
- Joint Research Centre (JRC), European Commission, Geel, Belgium.
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6
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Jobbágy V, Dupuis E, Emteborg H, Hult M. Performance evaluation of a European wide proficiency test on gross alpha/beta activity determination in drinking water. Appl Radiat Isot 2022; 186:110304. [DOI: 10.1016/j.apradiso.2022.110304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/22/2022] [Accepted: 05/18/2022] [Indexed: 11/02/2022]
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7
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Dosis I, Ricci M, Emteborg H, Emons H. A journey towards whole water certified reference materials for organic substances: measuring polycyclic aromatic hydrocarbons as required by the European Union Water Framework Directive. Anal Bioanal Chem 2021; 413:2283-2293. [PMID: 33598757 PMCID: PMC7987604 DOI: 10.1007/s00216-021-03200-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/15/2021] [Accepted: 01/25/2021] [Indexed: 10/28/2022]
Abstract
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.
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Affiliation(s)
- Ioannis Dosis
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
- German Environment Agency, Wörlitzer Platz 1, 06844, Dessau-Roßlau, Germany
| | - Marina Ricci
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium.
| | - Håkan Emteborg
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
| | - Hendrik Emons
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
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8
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Seghers J, Stefaniak EA, La Spina R, Cella C, Mehn D, Gilliland D, Held A, Jacobsson U, Emteborg H. Preparation of a reference material for microplastics in water-evaluation of homogeneity. Anal Bioanal Chem 2021; 414:385-397. [PMID: 33547482 PMCID: PMC8748356 DOI: 10.1007/s00216-021-03198-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/18/2021] [Accepted: 01/23/2021] [Indexed: 11/29/2022]
Abstract
Validation of analytical methods for measurements of microplastics (MP) is severely hampered because of a general lack of reference materials, RM. There is a great need to develop such reference materials. This study presents a concept of three-component kit with immobilised MP in solid NaCl, a surfactant and clean water that can be applied for the production of many types of MP RMs. As proof of concept, an RM for polyethylene terephthalate (PET) particles in water was prepared and evaluated for its homogeneity. The particles ranged from 30 μm (Feretmin) to about 200 μm adapted by wet sieving. A specific number of PET particles were immobilized in about 0.29 g of solid NaCl by freeze-drying 1 mL of a NaCl suspension. By using manual and automated counting, twenty reconstituted 1-L water samples were evaluated for homogeneity with respect to number of PET particles from 30 μm to > 200 μm/L of water. The number of particles was 730 ± 120 (mean ± one standard deviation (SD); n = 10) and 865 ± 155 particles (n = 10) obtained by optical microscopy in two independent laboratories. This corresponded to relative SDs of 16.4 and 17.9% and a mean of 797 ± 151 particles (18.9% RSD, for n = 20). Homogeneity studies of the NaCl carrier without reconstitution resulted in 794 ± 60 particles (7.5% RSD). The homogeneity of PET in the salt carrier was also evaluated directly with respect to mass of PET per vial using an ultra-micro balance. An average mass of 293 ± 41 μg of PET was obtained (14, % RSD for n = 14). Micrographs were recorded to demonstrate the absence of major sources of contamination of the RM components. Information about the particle size distribution and particle shapes was obtained by laser diffraction (LD) and dynamic image analysis (DIA). In addition, the identity of the PET polymer was confirmed by Raman and FT-IR spectroscopy. The RM was developed for a large-scale inter-laboratory comparison of PET particles in water (ILC). Based on the homogeneity results, the material was found to be sufficiently homogeneous to be of meaningful use in the ILC. In a 3-day process, more than 500 samples of PET particles in the NaCl carrier were prepared with good potential for further upscaling with respect to the number of vials or with other kinds of polymers. The stability of PET was not evaluated but it was deemed to be stable for the duration of the ILC.
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Affiliation(s)
- John Seghers
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
| | | | - Rita La Spina
- European Commission, Joint Research Centre (JRC), 21027, Ispra, Italy
| | - Claudia Cella
- European Commission, Joint Research Centre (JRC), 21027, Ispra, Italy
| | - Dora Mehn
- European Commission, Joint Research Centre (JRC), 21027, Ispra, Italy
| | - Douglas Gilliland
- European Commission, Joint Research Centre (JRC), 21027, Ispra, Italy
| | - Andrea Held
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
| | - Ulf Jacobsson
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium
| | - Håkan Emteborg
- European Commission, Joint Research Centre (JRC), 2440, Geel, Belgium.
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9
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Sobiech-Matura K, Lutter G, Van Ammel R, Marissens G, Hult M, Emteborg H. Evaluation of a proficiency test of 131I, 134Cs and 137Cs in maize powder. Appl Radiat Isot 2020; 162:109156. [PMID: 32310089 DOI: 10.1016/j.apradiso.2020.109156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 01/03/2020] [Accepted: 03/24/2020] [Indexed: 10/24/2022]
Abstract
In 2017, JRC-Geel organised a proficiency test for 120 participants on the massic activity determination of 131I, 134Cs and 137Cs in maize powder. The proficiency test reference material was produced by spiking blank maize powder. The material was characterised for its radioactive content using γ-ray spectrometry. The z scores of the reported massic activity were acceptable in 92% of the results for 131I, and in 94% for both 134Cs and 137Cs. The ζ scores were consistent with the reference value for 66% of the results for 131I, 56% for 134Cs and 68% for 137Cs.
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Affiliation(s)
- K Sobiech-Matura
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium.
| | - G Lutter
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium
| | - R Van Ammel
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium
| | - G Marissens
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium
| | - M Hult
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium
| | - H Emteborg
- European Commission, Joint Research Centre, Retieseweg 111, B-2440, Geel, Belgium
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10
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González de la Huebra MJ, Robouch P, Emteborg H, Bellorini S, Cizek-Stroh A, von Holst C. Application of the CEN/ISO Standard for Phytase Activity Measurements to a New Phytase Product: Determination of a Robust Conversion Factor by an Interlaboratory Study for Screening Feed Samples. J AOAC Int 2019; 102:1808-1813. [PMID: 31248472 DOI: 10.5740/jaoacint.19-0107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background: Phytase-based preparations are important feed additives currently authorised in the European Union (EU). The European Standard (EN) and International Organization for Standardization (ISO) standard 30024 describes a harmonized method for the determination of phytase activity and is fit-for-purpose for official control of a group of phytase products. However, it is not suitable for the determination of the phytase activity of a new feed additive encoded as 4a16 in the EU Register of Feed Additives, to which a slightly different phytase activity definition has been attributed. Objective: To establish a robust conversion factor to support official control laboratories that apply the EN ISO method when monitoring feed products containing 4a16. Methods: The phytase activity of test materials was determined by the participants using the EN ISO and/or the "applicant" methods. Results: Robust relative SDs for repeatability and for reproducibility of the methods applied for the determination of the phytase activity in the materials containing the 4a16 feed additive ranged from 2.6 to 22% (EN ISO method) and from 2.4 to 39% (applicant method). Conclusions: The data obtained confirmed the performance characteristics published for other phytase-based feeds in the related standard methods. These results allowed us to estimate a factor of 2.68 to convert phytase activities measured with the EN ISO method into the enzyme activity measured with the applicant method. Highlights: The obtained conversion factor will allow EU official laboratories to screen feed samples supplemented with the 4a16 phytase by applying EN ISO Standard 30024.
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Affiliation(s)
| | - Piotr Robouch
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Håkan Emteborg
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Stefano Bellorini
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Aneta Cizek-Stroh
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Christoph von Holst
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
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11
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González de la Huebra MJ, Robouch P, Emteborg H, Bellorini S, Cizek-Stroh A, von Holst C. Application of the CEN/ISO Standard for Phytase Activity Measurements to a New Phytase Product: Determination of a Robust Conversion Factor by an Interlaboratory Study for Screening Feed Samples. J AOAC Int 2019. [DOI: 10.1093/jaoac/102.6.1808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Background: Phytase-based preparations are important feed additives currently authorised in the European Union (EU). The European Standard (EN) and International Organization for Standardization (ISO) standard 30024 describes a harmonized method for the determination of phytase activity and is fit-for-purpose for official control of a group of phytase products. However, it is not suitable for the determination of the phytase activity of a new feed additive encoded as 4a16 in the EU Register of Feed Additives, to which a slightly different phytase activity definition has been attributed. Objective: To establish a robust conversion factor to support official control laboratories that apply the EN ISO method when monitoring feed products containing 4a16. Methods: The phytase activity of test materials was determined by the participants using the EN ISO and/or the “applicant” methods. Results: Robust relative SDs for repeatability and for reproducibility of the methods applied for the determination of the phytase activity in the materials containing the 4a16 feed additive ranged from 2.6 to 22% (EN ISO method) and from 2.4 to 39% (applicant method). Conclusions: The data obtained confirmed the performance characteristics published for other phytase-based feeds in the related standard methods. These results allowed us to estimate a factor of 2.68 to convert phytase activities measured with the EN ISO method into the enzyme activity measured with the applicant method. Highlights: The obtained conversion factor will allow EU official laboratories to screen feed samples supplemented with the 4a16 phytase by applying EN ISO Standard 30024.
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Affiliation(s)
| | - Piotr Robouch
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Håkan Emteborg
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Stefano Bellorini
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Aneta Cizek-Stroh
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
| | - Christoph von Holst
- European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium
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12
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Cordeiro F, Bratinova S, Karasek L, Buttinger G, Stroka J, Emteborg H, Seghers J, Robouch P, Emons H. Can official control laboratories quantify reliably fipronil in eggs? Evidence from a proficiency testing round. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2019; 36:904-910. [PMID: 31009319 DOI: 10.1080/19440049.2019.1602885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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.
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Affiliation(s)
| | | | - Lubomir Karasek
- a European Commission , Joint Research Centre , Geel , Belgium
| | | | - Joerg Stroka
- a European Commission , Joint Research Centre , Geel , Belgium
| | - Håkan Emteborg
- a European Commission , Joint Research Centre , Geel , Belgium
| | - John Seghers
- a European Commission , Joint Research Centre , Geel , Belgium
| | - Piotr Robouch
- a European Commission , Joint Research Centre , Geel , Belgium
| | - Hendrik Emons
- a European Commission , Joint Research Centre , Geel , Belgium
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Emteborg H, Florian D, Choquette S, Ellison SLR, Fernandes-Whaley M, Mackay L, McCarron P, Panne U, Sander SG, Kim SK, Held A, Linsinger T, Trapmann S. Cooperation in publicly funded reference material production. Accredit Qual Assur 2018; 23:10.1007/s00769-018-1349-1. [PMID: 34131366 PMCID: PMC8201643 DOI: 10.1007/s00769-018-1349-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/23/2018] [Indexed: 06/10/2023]
Affiliation(s)
- Håkan Emteborg
- European Commission Joint Research Centre (JRC), Geel, Belgium
| | - Doris Florian
- European Commission Joint Research Centre (JRC), Geel, Belgium
| | - Steven Choquette
- National Institute of Standards and Technology (NIST), Gaithersburg, USA
| | | | | | - Lindsey Mackay
- National Measurement Institute of Australia (NMIA), Lindfield, Australia
| | | | - Ulrich Panne
- Bundesanstalt für Materialforschung und –prüfung (BAM), Berlin, Germany
| | - Sylvia G. Sander
- International Atomic Energy Agency (IAEA) Environment Laboratories, Monaco City, Monaco
| | - Sook-Kyung Kim
- Korea Institute of Standards and Science (KRISS), Daejeon, South Korea
| | - Andrea Held
- European Commission Joint Research Centre (JRC), Geel, Belgium
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Dosis I, Ricci M, Majoros L, Lava R, Emteborg H, Held A, Emons H. Addressing Analytical Challenges of the Environmental Monitoring for the Water Framework Directive: ERM-CE100, a New Biota Certified Reference Material. Anal Chem 2017; 89:2514-2521. [DOI: 10.1021/acs.analchem.6b04682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ioannis Dosis
- European
Commission, Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
| | - Marina Ricci
- European
Commission, Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
| | - Laszlo Majoros
- European Chemicals
Agency, Annankatu 18, Helsinki 00121, Finland
| | - Roberto Lava
- Regional Environmental Protection and Prevention Agency for Veneto, Regional Laboratories Department, Via Lissa 6, 30174 Mestre-Venice, Italy
| | - Håkan Emteborg
- European
Commission, Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
| | - Andrea Held
- European
Commission, Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
| | - Hendrik Emons
- European
Commission, Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
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Fiamegos Y, Vahcic M, Emteborg H, Snell J, Raber G, Cordeiro F, Robouch P, de la Calle B. Determination of toxic trace elements in canned vegetables. The importance of sample preparation. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McCarron P, Wright E, Emteborg H, Quilliam MA. A mussel tissue certified reference material for multiple phycotoxins. Part 4: certification. Anal Bioanal Chem 2016; 409:95-106. [PMID: 27830316 DOI: 10.1007/s00216-016-0004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/04/2016] [Indexed: 11/26/2022]
Abstract
A freeze-dried mussel tissue (Mytilus edulis) reference material (CRM-FDMT1) was produced containing multiple groups of shellfish toxins. Homogeneity and stability testing showed the material to be fit for purpose. The next phase of work was to assign certified values and uncertainties to 10 analytes from six different toxin groups. Efforts involved optimizing extraction procedures for the various toxin groups and performing measurements using liquid chromatography-based analytical methods. A key aspect of the work was compensating for matrix effects associated with liquid chromatography-mass spectrometry through standard addition, dilution, or matrix-matched calibration. Certified mass fraction values are reported as mg/kg of CRM-FDMT1 powder as bottled for azaspiracid-1, -2, and -3 (4.10 ± 0.40; 1.13± 0.10; 0.96 ± 0.10, respectively), okadaic acid, dinophysistoxin-1 and -2 (1.59 ± 0.18; 0.68 ± 0.07; 3.57± 0.33, respectively), yessotoxin (2.49 ± 0.28), pectenotoxin-2 (0.66 ± 0.06), 13-desmethylspirolide-C (2.70 ± 0.26), and domoic acid (126 ± 10). Combined uncertainties for the certified values include contributions from homogeneity, stability, and characterization experiments. The commutability of CRM-FDMT1 was assessed by examining the extractability and matrix effects for the freeze-dried material in comparison with its equivalent wet tissue homogenate. CRM-FDMT1 is the first shellfish matrix CRM with certified values for yessotoxins, pectenotoxins or spirolides, and is the first CRM certified for multiple toxin groups. CRM-FDMT1 is a valuable tool for quality assurance of phycotoxin monitoring programs and for analytical method development and validation. Graphical Abstract CRM-FDMT1 is a multi-toxin mussel tissue certified reference material (CRM) to aid in development and validation of analytical methods for measuring the levels of algal toxins in seafood.
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Affiliation(s)
- Pearse McCarron
- Measurement Science and Standards, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada.
| | - Elliott Wright
- Measurement Science and Standards, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada
| | - Håkan Emteborg
- European Commission, Joint Research Centre, Directorate F - Health, Consumers, and Reference Materials, Retieseweg 111, 2440, Geel, Belgium
| | - Michael A Quilliam
- Measurement Science and Standards, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia, B3H 3Z1, Canada
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17
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Fiamegkos I, Cordeiro F, Robouch P, Vélez D, Devesa V, Raber G, Sloth JJ, Rasmussen RR, Llorente-Mirandes T, Lopez-Sanchez JF, Rubio R, Cubadda F, D'Amato M, Feldmann J, Raab A, Emteborg H, de la Calle MB. Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food: Outcome of the collaborative trial IMEP-41. Food Chem 2016; 213:169-179. [PMID: 27451169 DOI: 10.1016/j.foodchem.2016.06.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/22/2016] [Accepted: 06/12/2016] [Indexed: 10/21/2022]
Abstract
A collaborative trial was conducted to determine the performance characteristics of an analytical method for the quantification of inorganic arsenic (iAs) in food. The method is based on (i) solubilisation of the protein matrix with concentrated hydrochloric acid to denature proteins and allow the release of all arsenic species into solution, and (ii) subsequent extraction of the inorganic arsenic present in the acid medium using chloroform followed by back-extraction to acidic medium. The final detection and quantification is done by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). The seven test items used in this exercise were reference materials covering a broad range of matrices: mussels, cabbage, seaweed (hijiki), fish protein, rice, wheat, mushrooms, with concentrations ranging from 0.074 to 7.55mgkg(-1). The relative standard deviation for repeatability (RSDr) ranged from 4.1 to 10.3%, while the relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 22.8%.
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Affiliation(s)
- I Fiamegkos
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 111 Retieseweg, 2440 Geel, Belgium
| | - F Cordeiro
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 111 Retieseweg, 2440 Geel, Belgium
| | - P Robouch
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 111 Retieseweg, 2440 Geel, Belgium
| | - D Vélez
- Metal Contamination Laboratory (IATA-CSIC), Avd. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - V Devesa
- Metal Contamination Laboratory (IATA-CSIC), Avd. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - G Raber
- Institute of Chemistry, University of Graz, Universitätsplatz 1, 8010 Graz, Austria
| | - J J Sloth
- Technical University of Denmark, National Food Institute, Division of Food Chemistry, Mørkhøj Bygade 19, 2860 Søborg, Denmark
| | - R R Rasmussen
- Technical University of Denmark, National Food Institute, Division of Food Chemistry, Mørkhøj Bygade 19, 2860 Søborg, Denmark
| | - T Llorente-Mirandes
- Department of Analytical Chemistry, University of Barcelona, Martí I Franque's 1-11, 08028 Barcelona, Spain
| | - J F Lopez-Sanchez
- Department of Analytical Chemistry, University of Barcelona, Martí I Franque's 1-11, 08028 Barcelona, Spain
| | - R Rubio
- Department of Analytical Chemistry, University of Barcelona, Martí I Franque's 1-11, 08028 Barcelona, Spain
| | - F Cubadda
- Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità-Italian National Health Institute, Viale Regina Elena 299, 00161 Rome, Italy
| | - M D'Amato
- Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità-Italian National Health Institute, Viale Regina Elena 299, 00161 Rome, Italy
| | - J Feldmann
- Trace Element Speciation Laboratory (TESLA), University of Aberdeen, College of Physical Science, Chemistry, Meston Walk, Aberdeen AB24 3UE, Scotland, United Kingdom
| | - A Raab
- Trace Element Speciation Laboratory (TESLA), University of Aberdeen, College of Physical Science, Chemistry, Meston Walk, Aberdeen AB24 3UE, Scotland, United Kingdom
| | - H Emteborg
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 111 Retieseweg, 2440 Geel, Belgium
| | - M B de la Calle
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 111 Retieseweg, 2440 Geel, Belgium.
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Jobbágy V, Merešová J, Dupuis E, Kwakman P, Altzitzoglou T, Rožkov A, Hult M, Emteborg H, Wätjen U. Results of a European interlaboratory comparison on gross alpha/beta activity determination in drinking water. J Radioanal Nucl Chem 2015; 306:325-331. [PMID: 26366031 PMCID: PMC4561063 DOI: 10.1007/s10967-015-3955-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Indexed: 11/11/2022]
Abstract
An interlaboratory comparison was organised by JRC-IRMM among environmental radioactivity monitoring laboratories for the determination of gross alpha/beta activity concentration in drinking water. Independent standard methods were used for the reference value determination. The performance of participating laboratories was evaluated with respect to the reference values using relative deviations. Sample preparation and measurement methods used by the participating laboratories are detailed, in particular in the view of method-dependency of the results. Many of the participants’ results deviate by more than two orders of magnitude from the reference values regardless of the techniques used. This suggests that gross methods need revision.
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Affiliation(s)
- Viktor Jobbágy
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium ; Waste and Disposal Expert Group, Institute for Environment, Health and Safety, SCK•CEN, Boeretang 200, 2400 Mol, Belgium
| | - Jana Merešová
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Edmond Dupuis
- Low Level Radioactivity Measurements Expert Group, Institute for Environment, Health and Safety, SCK•CEN, Boeretang 200, 2400 Mol, Belgium
| | - Pieter Kwakman
- Laboratory for Radiation Research, RIVM, PO Box 1, 3720 BA Bilthoven, The Netherlands
| | - Timotheos Altzitzoglou
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Andrej Rožkov
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Mikael Hult
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Håkan Emteborg
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Uwe Wätjen
- Joint Research Centre, Institute for Reference Materials and Measurements (JRC-IRMM), European Commission, Retieseweg 111, 2440 Geel, Belgium ; Kievermondeveld 74, 2440 Geel, Belgium
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Huertas-Pérez JF, Bordajandi LR, Sejerøe-Olsen B, Emteborg H, Baù A, Schimmel H, Dabrio M. PAHs in baby food: assessment of three different processing techniques for the preparation of reference materials. Anal Bioanal Chem 2015; 407:3069-81. [PMID: 25644522 PMCID: PMC4383830 DOI: 10.1007/s00216-015-8490-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/01/2015] [Accepted: 01/13/2015] [Indexed: 11/11/2022]
Abstract
A feasibility study for producing a matrix reference material for selected polycyclic aromatic hydrocarbons (PAHs) in baby food is reported. A commercially available baby food, containing carrots, potatoes, tomato, white beans and meat, was spiked with the so-called 15 + 1 PAHs included in the PAHs priority list for food of the EU, at a mass fraction level of 1 μg/kg. The contaminated baby food was further processed by autoclaving, freezing or freeze drying. The homogeneity of the three materials (bottle-to-bottle variation) and their short-term (4 weeks) and long-term (18 months) stability at different temperatures were assessed. To this end, an analytical method based on a solid–liquid extraction followed by cleaning up with gel permeation chromatography (GPC) and solid phase extraction (SPE) and GC-IDMS determination, was validated in-house. It could be demonstrated that the procedure fulfilled the demands for application to the homogeneity and isochronous stability studies for the candidate reference materials targeted here. All three materials proved to be sufficiently homogeneous for the intended use. Measurements on the autoclaved material provided the most promising results in terms of envisaged shelf life, although freeze drying was also found to be a suitable processing technique for most of the investigated PAHs. These results are an important step towards the development of a matrix reference material for PAHs in a processed food matrix in a presentation very similar to routine samples.
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Affiliation(s)
- José Fernando Huertas-Pérez
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440, Geel, Belgium,
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Cordeiro F, Llorente-Mirandes T, López-Sánchez J, Rubio R, Sánchez Agullo A, Raber G, Scharf H, Vélez D, Devesa V, Fiamegos Y, Emteborg H, Seghers J, Robouch P, de la Calle M. Determination of total cadmium, lead, arsenic, mercury and inorganic arsenic in mushrooms: outcome of IMEP-116 and IMEP-39. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014; 32:54-67. [PMID: 25365736 PMCID: PMC4299854 DOI: 10.1080/19440049.2014.966336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/12/2014] [Indexed: 12/04/2022]
Abstract
The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate General of the European Commission, operates the International Measurement Evaluation Program (IMEP). IMEP organises inter-laboratory comparisons in support of European Union policies. This paper presents the results of two proficiency tests (PTs): IMEP-116 and IMEP-39, organised for the determination of total Cd, Pb, As, Hg and inorganic As (iAs) in mushrooms. Participation in IMEP-116 was restricted to National Reference Laboratories (NRLs) officially appointed by national authorities in European Union member states. IMEP-39 was open to all other laboratories wishing to participate. Thirty-seven participants from 25 countries reported results in IMEP-116, and 62 laboratories from 36 countries reported for the IMEP-39 study. Both PTs were organised in support to Regulation (EC) No. 1881/2006, which sets the maximum levels for certain contaminants in food. The test item used in both PTs was a blend of mushrooms of the variety shiitake (Lentinula edodes). Five laboratories, with demonstrated measurement capability in the field, provided results to establish the assigned values (Xref). The standard uncertainties associated 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), whilst uchar was calculated following ISO 13528. Laboratory results were rated with z- and zeta (ζ)-scores in accordance with ISO 13528. The standard deviation for proficiency assessment, σp, ranged from 10% to 20% depending on the analyte. The percentage of satisfactory z-scores ranged from 81% (iAs) to 97% (total Cd) in IMEP-116 and from 64% (iAs) to 84% (total Hg) in IMEP-39.
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Affiliation(s)
- F. Cordeiro
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | | | - J.F. López-Sánchez
- Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain
| | - R. Rubio
- Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain
| | | | - G. Raber
- Institute of Chemistry, Karl Franzes University Graz, Graz, Austria
| | - H. Scharf
- BAM Federal Institute for Materials Research and Testing, Division 1.6: Inorganic Reference Materials, Berlin, Germany
| | - D. Vélez
- Metal Contamination Laboratory (IATA-CSIC), Paterna, Valencia, Spain
| | - V. Devesa
- Metal Contamination Laboratory (IATA-CSIC), Paterna, Valencia, Spain
| | - Y. Fiamegos
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - H. Emteborg
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - J. Seghers
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - P. Robouch
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - M.B. de la Calle
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
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Emteborg H, Zeleny R, Charoud-Got J, Martos G, Lüddeke J, Schellin H, Teipel K. Infrared thermography for monitoring of freeze-drying processes: instrumental developments and preliminary results. J Pharm Sci 2014; 103:2088-2097. [PMID: 24902839 PMCID: PMC4303947 DOI: 10.1002/jps.24017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/03/2014] [Accepted: 05/02/2014] [Indexed: 11/21/2022]
Abstract
Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from −40°C to 25°C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5°C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8°C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13°C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10°C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. © 2014 European Union 103:2088–2097, 2014
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Affiliation(s)
- Håkan Emteborg
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, (IRMM) Retieseweg 111, B-2440 Geel, Belgium.
| | - Reinhard Zeleny
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, (IRMM) Retieseweg 111, B-2440 Geel, Belgium
| | - Jean Charoud-Got
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, (IRMM) Retieseweg 111, B-2440 Geel, Belgium
| | - Gustavo Martos
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, (IRMM) Retieseweg 111, B-2440 Geel, Belgium
| | - Jörg Lüddeke
- Martin Christ Gefriertrocknungsanlagen GmbH, An der Unteren Söse 50, D-37520 Osterode, Germany
| | - Holger Schellin
- InfraTec GmbH Infrarotsensorik und Messtechnik, Gostritzer Str. 61-63, D-01217 Dresden, Germany
| | - Katharina Teipel
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, (IRMM) Retieseweg 111, B-2440 Geel, Belgium
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Wätjen U, Spasova Y, Vasile M, Szántó Z, Emteborg H, Voitsekhovych O. Certification of the reference material IRMM-426 for radionuclides in dried bilberries. Appl Radiat Isot 2014; 87:475-9. [DOI: 10.1016/j.apradiso.2013.11.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/27/2013] [Indexed: 10/25/2022]
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Fiamegos Y, Cordeiro F, Robouch P, Emteborg H, Charoud-Got J, Omberg LG, Rodushkin I, de la Calle B. Feed premix: a difficult matrix for the accurate determination of trace elements - the outcome of IMEP-114 and IMEP-36. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 31:63-72. [PMID: 24195486 DOI: 10.1080/19440049.2013.861083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This paper presents the outcome of two proficiency tests (IMEP-114/36) running in parallel, which focused on the determination of total As, Cd, Pb, Hg and Sn in feed premixes. Both exercises aimed to test the performance of laboratories measuring trace elements in feed, in compliance with Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. IMEP-114 was run for the European Union National Reference Laboratories, while IMEP-36 was open to all food control laboratories that wished to participate. In total 80 laboratories from 37 countries registered to both proficiency tests, from which 75 laboratories reported results. The test material used in this exercise was commercially available feed premix, which was processed, bottled, labelled and dispatched to participants. The performance of the participating laboratories was similar in both proficiency tests and was very good in the case of total Cd and less satisfactory for total As and total Pb. For total Sn only one-third of the participants reported results, from which 33% performed satisfactorily. Thirty-four participants reported results for total Hg, although the expert laboratories stated that the mass fraction for that measurand was below the limit of detection of the method used. An evaluation of the reasons that could be at the basis of unsatisfactory results has been carried out and is presented here.
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Affiliation(s)
- Yiannis Fiamegos
- a European Commission , Directorate General Joint Research Centre, Institute for Reference Materials and Measurements , Geel , Belgium
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Cordeiro F, Baer I, Robouch P, Emteborg H, Can SZ, Krata A, Zampella M, Quétel CR, Hearn R, De la Calle B. Setting maximum limits for trace elements in baby food in European legislation: the outcome of International Measurement Evaluation Programme®-33. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 30:678-86. [PMID: 23544660 DOI: 10.1080/19440049.2013.775605] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate-General of the European Commission, operates the International Measurement Evaluation Programme® (IMEP). It organises various types of inter-laboratory comparisons in support of European Union policies. This paper presents the results of a proficiency testing exercise (PT) focusing on the determination of total cadmium (Cd) and total lead (Pb) mass fractions in baby food in support to Commission Regulation (EC) 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. The test material used in this exercise was soya-based baby food formula purchased in a local pharmacy and prepared by the Reference Materials Unit of the IRMM for this exercise. Sixty-six laboratories from 23 countries registered to the exercise and 61 of them reported results. Each participant received one bottle containing approximately 15 g of test material. Participants were asked to quantify the measurands in the powder and in the reconstituted formula. Reference values independent from the participants' results were established using isotope dilution inductively coupled plasma mass spectrometry. The total Cd mass fraction was determined by IRMM and LGC Ltd (UK), while the total Pb was determined by IRMM. The standard deviation for proficiency assessment σ^ was set at 22% of the assigned value for all measurands. Laboratories were rated with z- and ζ- (zeta) scores in accordance with ISO 13528. The outcome of this exercise is clearly influenced by the very low level of Cd and Pb content in the test material which triggered: a high number of 'less than' values; overestimated values especially for Pb very likely due to contamination; and a visible method influence in the case of Pb (methods based on atomic absorption were not sensitive enough to attain such low limits of detection). The results were also evaluated with regard to the reported limit of detection and some incoherencies were observed.
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Affiliation(s)
- F Cordeiro
- European Commission, Directorate General Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium.
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de la Calle MB, Baer I, Robouch P, Cordeiro F, Emteborg H, Baxter MJ, Brereton N, Raber G, Velez D, Devesa V, Rubio R, Llorente-Mirandes T, Raab A, Feldmann J, Sloth JJ, Rasmussen RR, D'Amato M, Cubadda F. Is it possible to agree on a value for inorganic arsenic in food? The outcome of IMEP-112. Anal Bioanal Chem 2012; 404:2475-88. [PMID: 22986988 DOI: 10.1007/s00216-012-6398-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/24/2012] [Accepted: 08/29/2012] [Indexed: 11/24/2022]
Abstract
Two of the core tasks of the European Union Reference Laboratory for Heavy Metals in Feed and Food (EU-RL-HM) are to provide advice to the Directorate General for Health and Consumers (DG SANCO) on scientific matters and to organise proficiency tests among appointed National Reference Laboratories. This article presents the results of the 12th proficiency test organised by the EU-RL-HM (IMEP-112) that focused on the determination of total and inorganic arsenic in wheat, vegetable food and algae. The test items used in this exercise were: wheat sampled in a field with a high concentration of arsenic in the soil, spinach (SRM 1570a from NIST) and an algae candidate reference material. Participation in this exercise was open to laboratories from all around the world to be able to judge the state of the art of the determination of total and, more in particular, inorganic arsenic in several food commodities. Seventy-four laboratories from 31 countries registered to the exercise; 30 of them were European National Reference Laboratories. The assigned values for IMEP-112 were provided by a group of seven laboratories expert in the field of arsenic speciation analysis in food. Laboratory results were rated with z and ζ scores (zeta scores) in accordance with ISO 13528. Around 85 % of the participants performed satisfactorily for inorganic arsenic in vegetable food and 60 % did for inorganic arsenic in wheat, but only 20 % of the laboratories taking part in the exercise were able to report satisfactory results in the algae test material.
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Affiliation(s)
- M B de la Calle
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, Geel, Belgium.
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26
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Wätjen U, Altzitzoglou T, Ceccatelli A, Dikmen H, Emteborg H, Ferreux L, Frechou C, La Rosa J, Luca A, Moreno Y, Oropesa P, Pierre S, Schmiedel M, Spasova Y, Szántó Z, Szücs L, Wershofen H, Yücel Ü. Results of an international comparison for the determination of radionuclide activity in bilberry material. Appl Radiat Isot 2012; 70:1843-9. [DOI: 10.1016/j.apradiso.2012.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Accepted: 02/16/2012] [Indexed: 10/28/2022]
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27
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de la Calle Guntiñas M, Semeraro A, Wysocka I, Cordeiro F, Quétel C, Emteborg H, Charoud-Got J, Linsinger T. Proficiency test for the determination of heavy metals in mineral feed. The importance of correctly selecting the certified reference materials during method validation. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2011; 28:1534-46. [DOI: 10.1080/19440049.2011.590455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Baer I, Emteborg H, de la Calle B. Results from two interlaboratory comparisons on the measurement of trace element contents in food supplements – State of the art of control laboratories in Europe. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.12.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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de la Calle M, Emteborg H, Linsinger T, Montoro R, Sloth J, Rubio R, Baxter M, Feldmann J, Vermaercke P, Raber G. Does the determination of inorganic arsenic in rice depend on the method? Trends Analyt Chem 2011. [DOI: 10.1016/j.trac.2010.11.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McCarron P, Emteborg H, Giddings SD, Wright E, Quilliam MA. A mussel tissue certified reference material for multiple phycotoxins. Part 3: homogeneity and stability. Anal Bioanal Chem 2011; 400:847-58. [PMID: 21380752 DOI: 10.1007/s00216-011-4787-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 02/06/2011] [Accepted: 02/07/2011] [Indexed: 11/27/2022]
Abstract
A candidate certified reference material (CRM) for multiple shellfish toxins (domoic acid, okadaic acid and dinophysistoxins, pectenotoxins, yessotoxin, azaspiracids and spirolides) has been prepared as a freeze-dried powder from mussel tissues (Mytilus edulis). Along with the certified values, the most important characteristics for a reference material to be fit-for-purpose are homogeneity and stability. Acceptable between-bottle homogeneity was found for this CRM. Within-bottle homogeneity was assessed using domoic acid, and it was shown that repeated subsampling of the CRM can be performed precisely down to 0.35 g. Both short- and long-term stability studies carried out under isochronous conditions demonstrated excellent stability of the various toxins present in the material. While degradation of some analytes was observed at +60°C in short-term studies, it was determined that shipping at ambient temperature is adequate. No instability was detected in long-term stability studies, and it was shown that the material can be held at +18°C safely for up to 1 year. To guarantee stability of the CRM over its lifetime the stock will be maintained at -20°C. The results of the homogeneity and stability testing show that CRM-FDMT1 is appropriate for its intended use in quality assurance and quality control of shellfish toxin analysis methods.
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Affiliation(s)
- Pearse McCarron
- National Research Council Canada, Institute for Marine Biosciences, Halifax, NS, Canada.
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de la Calle Guntiñas M, Wysocka I, Quétel C, Vassileva E, Robouch P, Emteborg H, Taylor P. Proficiency test for heavy metals in feed and food in Europe. Trends Analyt Chem 2009. [DOI: 10.1016/j.trac.2009.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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32
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Kestens V, Charoud-Got J, Bau’ A, Bernreuther A, Emteborg H. Online measurement of water content in candidate reference materials by acousto-optical tuneable filter near-infrared spectrometry (AOTF-NIR) using pork meat calibrants controlled by Karl Fischer titration. Food Chem 2008. [DOI: 10.1016/j.foodchem.2007.01.081] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Broothaerts W, Corbisier P, Emons H, Emteborg H, Linsinger TPJ, Trapmann S. Development of a certified reference material for genetically modified potato with altered starch composition. J Agric Food Chem 2007; 55:4728-34. [PMID: 17508757 DOI: 10.1021/jf0701584] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The presence of genetically modified organisms (GMOs) in food and feed products is subject to regulation in the European Union (EU) and elsewhere. As part of the EU authorization procedure for GMOs intended for food and feed use, reference materials must be produced for the quality control of measurements to quantify the GMOs. Certified reference materials (CRMs) are available for a range of herbicide- and insect-resistant genetically modified crops such as corn, soybean, and cotton. Here the development of the first CRM for a GMO that differs from its non-GMO counterpart in a major compositional constituent, that is, starch, is described. It is shown that the modification of the starch composition of potato (Solanum tuberosum L.) tubers, together with other characteristics of the delivered materials, have important consequences for the certification strategy. Moreover, the processing and characterization of the EH92-527-1 potato material required both new and modified procedures, different from those used routinely for CRMs produced from genetically modified seeds.
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Affiliation(s)
- Wim Broothaerts
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel, Belgium.
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Krska R, Schubert-Ullrich P, Josephs RD, Emteborg H, Buttinger G, Pettersson H, van Egmond HP, Schothorst RC, Macdonald S, Chan D. Determination of molar absorptivity coefficients for major type-B trichothecenes and certification of calibrators for deoxynivalenol and nivalenol. Anal Bioanal Chem 2007; 388:1215-26. [PMID: 17551715 DOI: 10.1007/s00216-007-1369-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 05/07/2007] [Accepted: 05/11/2007] [Indexed: 11/24/2022]
Abstract
This paper presents results from the European Commission-funded project Doncalibrant, the objective of which was to produce calibrators with certified mass fractions of the Fusarium toxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-Ac-DON), 15-acetyldeoxynivalenol (15-Ac-DON), and nivalenol (NIV), in acetonitrile. The calibrators, available in ampoules, were sufficiently homogeneous, with between-bottle variations (s (bb)) of less than 2%. Long-term stability studies performed at four different temperatures between -18 and 40 degrees C revealed no significant negative trends (at a confidence level of 95%). Molar absorptivity coefficients (in L mol(-1) cm(-1)) were determined for all four toxins (DON: 6805 +/- 126, NIV: 6955 +/- 205, 3-Ac-DON: 6983 +/- 141, 15-Ac-DON: 6935 +/- 142) on the basis of a mini-interlaboratory exercise. The overall uncertainty of the calibrators' target values for DON and NIV were evaluated on the basis of gravimetric preparation data and include uncertainty contributions from possible heterogeneity, storage, and transport. The Doncalibrant project resulted in the production of calibrators for DON (IRMM-315) and NIV (IRMM-316) in acetonitrile with certified mass fractions of 25.1 +/- 1.2 microg g(-1) and 24.0 +/- 1.1 microg g(-1), respectively. Both CRMs became commercially available from the Institute for Reference Materials and Measurements (IRMM, Geel, Belgium) at the beginning of 2007.
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Affiliation(s)
- Rudolf Krska
- Centre for Analytical Chemistry, University of Natural Resources and Applied Life Sciences Vienna, Department for Agrobiotechnology (IFA Tulln), Konrad Lorenz Strasse 20, Tulln, Austria.
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McCarron P, Emteborg H, Hess P. Freeze-drying for the stabilisation of shellfish toxins in mussel tissue (Mytilus edulis) reference materials. Anal Bioanal Chem 2007; 387:2475-86. [PMID: 17256111 DOI: 10.1007/s00216-006-1104-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 12/16/2006] [Accepted: 12/18/2006] [Indexed: 11/29/2022]
Abstract
Two samples of mussels (Mytilus edulis) were collected from the southwest of Ireland. One sample contained domoic acid, the other sample contained okadaic acid, dinophysistoxin-2 and azaspiracid-1, -2 and -3. Wet and freeze-dried reference materials were prepared from each of the two samples to test for differences in homogeneity, stability and extractability of the analytes in either condition. Wet materials were homogenised, aliquoted and hermetically sealed under argon and subsequently frozen at -80 degrees C. Dry materials were similarly homogenised but frozen in flat cakes prior to freeze-drying. After grinding, sieving and further homogenisation, the resulting powder was aliquoted and hermetically sealed. Domoic acid materials were characterised using HPLC-UV, while LC-MS was used for the determination of lipophilic toxins. The extractabilities of all phycotoxins studied were comparable for wet and freeze-dried materials once a sonication step had been carried out for reconstitution of the freeze-dried materials prior to extraction. Homogeneity was assessed through replicate analysis of the phycotoxins (n = 10), and was found to be similar for wet and freeze-dried materials, for both hydrophilic and lipophilic toxins. Water contents were determined for both wet and freeze-dried materials, and particle size was determined for the freeze-dried materials. Stability was evaluated isochronously over eight months at four temperatures (-20, +4, +20 and +40 degrees C). The freeze-dried material containing domoic acid was stable over the whole duration at all temperatures, while in the wet material domoic acid degraded to some extent at all temperatures except -20 degrees C. In freeze-dried and wet materials containing lipophilic toxins, okadaic acid, dinophysistoxin-2, azaspiracid-1 and azaspiracid-2 were stable over the whole duration at all conditions, while concentrations of azaspiracid-3 changed significantly in both materials at some storage temperatures. Figure Aliquots of freeze-dried and wet mussel tissue reference materials containing the various shellfish toxins examined in the study.
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Affiliation(s)
- Pearse McCarron
- Marine Institute, Marine Environment and Food Safety Service, Rinville, Oranmore, Galway, Ireland.
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36
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Emteborg H, Bordin G. Speciation of organic and inorganic selenium in a biological certified reference material based on microbore ion-exchange chromatography coupled to inductively coupled plasma atomic emission spectrometry via a direct injection nebulizer or coupled to electrothermal atomic absorption spectrometry. Analyst 1998. [DOI: 10.1039/a705967a] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Emteborg H, Bordin G, Rodriguez AR. Speciation of selenium in aqueous and biological matrices by microbore ion chromatography coupled with electrothermal atomic absorption spectrometry via ultra low volume fraction collection†. Analyst 1998. [DOI: 10.1039/a707450f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Emteborg H, Björklund E, Ödman F, Karlsson L, Mathiasson L, Frech W, Baxter DC. Determination of methylmercury in sediments using supercritical fluid extraction and gas chromatography coupled with microwave-induced plasma atomic emission spectrometry. Analyst 1996. [DOI: 10.1039/an9962100019] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Hänström S, Briche C, Emteborg H, Baxter DC. Large-volume injections in capillary gas chromatography using a separately heated packed pre-column: application to mercury speciation in natural water. Analyst 1996. [DOI: 10.1039/an9962101657] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Bulska E, Emteborg H, Baxter DC, Frech W, Ellingsen D, Thomassen Y. Speciation of mercury in human whole blood by capillary gas chromatography with a microwave-induced plasma emission detector system following complexometric extraction and butylation. Analyst 1992; 117:657-63. [PMID: 1580415 DOI: 10.1039/an9921700657] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Methyl- and inorganic mercury were extracted from human whole blood samples, as their diethyldithiocarbamate complexes, into toluene and butylated by using a Grignard reagent. The mercury species were then separated by gas chromatography (on a 12 m non-polar DB-1 capillary column) and detected by a microwave-induced plasma atomic emission spectrometric (GC-MPD) system. The accuracy and precision of the proposed method were established by the analysis of Seronorm lyophilized human whole blood standards for methyl- and inorganic mercury. No statistical difference (t-test) between the sum of these two species determined by the GC-MPD based method and the recommended total mercury concentrations in the Seronorm samples was observed. Results for the determination of methyl- and inorganic mercury in 60 controls and 90 previously occupationally exposed (to inorganic mercury) workers are presented to illustrate the practical utility of the proposed method. No significantly elevated inorganic mercury concentrations between the two groups were evident.
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Affiliation(s)
- E Bulska
- Department of Analytical Chemistry, University of Umeå, Sweden
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