The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate-General of the European Commission, operates the Community Reference Laboratory for Heavy Metals in Feed and Food (CRL-HM). One of its core tasks is to organise interlaboratory comparisons (ILCs) among appointed National Reference Laboratories (NRLs). This report presents the results of the fourth ILC of the CRL-HM which focused on the determination of total Cd, Pb, As, Hg and methylmercury (related to dry mass) in seafood. The test material used in this exercise was the Certified Reference Material (CRM) TORT-2, lobster hepatopancreas, of the National Research Council of Canada. The material was rebottled and relabelled to prevent recognition by the participants and it was dispatched on the first half of May 2008. Each participant received one bottle containing approximately 20 g of test material. Thirty-four participants from twenty-six countries registered to the exercise of which 33 sets of results were reported for Cd and total mercury, 32 for Pb, 27 for arsenic and 4 for methylmercury. One laboratory reported two sets of values for Cd, Pb, Hg and As obtained with two different techniques, respectively. The Assigned values were the certified values taken from the TORT-2 certificate. The uncertainties of the respective assigned values, uref, were taken directly from the CRM certificate as provided by the producer. Participants were invited to report the uncertainty on their measurements. This was done by all the laboratories taking part in this exercise. Laboratory results were rated with z and zeta scores in accordance with ISO 13528. Standard deviation for proficiency assessment (also called target standard deviation) were calculated using the modified Horwitz equation and were 9.76 % for total Cd, 18. 74 % for total Pb, 10 % for total As, 19.48 % for total Hg and 21.24 % for methylmercury. How to obtain EU publications Our priced publications are available from EU Bookshop (http://bookshop.europa.eu), where you can place an order with the sales agent of your choice. The Publications Office has a worldwide network of sales agents. You can obtain their contact details by sending a fax to (352) 29 29-42758. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC functions as a reference centre of science and technology for the Union. Close to the policy-making process, it serves the common interest of the Member States, while being independent of special interests, whether private or national. LA -N A -2305-EN -C
The key comparison CCQM-K108.2014 was organised by the Inorganic Analysis Working Group (IAWG) of CCQM to test the abilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of inorganic arsenic (i-As, sum of the amount of arsenite [As(III)] and arsenate [As(V)]), dimethylarsinic acid (DMAA), and total arsenic (total As) in brown rice flour. This was the follow-up comparison for the CCQM-K108 & CCQM-P147 (Cd, As, inorganic arsenic, and DMAA in brown rice flour). For total As, no strong outliers among the reported values were observed, and the distribution of the results was narrow, within 3% around the median. For i-As and DMAA, the distributions of the results were slightly wider than that for total arsenic, but no strong outliers among the reported values of i-As and DMAA were observed. Two potentially bias sources, an extraction efficiency of As species (the ratio of the sum of i-As and DMAA to total As) and the quality of primary standard of DMAA, were discussed. The extraction efficiency was estimated as the ratio of the sum of i-As and DMAA to total As. In the previous comparison (CCQM-K108 & CCQM-P147), the extraction efficiency was one of the largest bias sources for i-As and DMAA. However, in this study, all the extraction efficiencies estimated from the reported values were close to 100 %. Regarding the quality of the primary standard solutions, no significant difference was observed among the primary standard solution used by the participants. These results suggest the two potential bias sources mentioned above would not have been majors in this study, and then the technical issues in the previous comparison had been overcome. Accounting for relative expanded uncertainty, a comparability of measurement was successfully demonstrated by the participating NMIs and DIs for the measurement of total As at the level of less than 0.7 mg/kg, i-As at the level of less than 0.6 mg/kg, and DMAA at the level of less than 0.1 mg/kg. These are expected that total arsenic and i-As at mass fractions greater than 0.1 mg/kg and DMAA at mass fractions greater than 0.005 mg/kg in rice flour can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report. Furthermore, the results of this key comparison can be utilised along with the IAWG core capability approach. Main text To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ . The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Over the last several decades, considerable contamination by hexavalent chromium has resulted from the land disposal of Chromite Ore Processing Residue (COPR). COPR contains a number of hexavalent chromium-bearing compounds that were produced in high temperature industrial processes. Concern over the carcinogenic potential of this chromium species, and its environmental mobility, has resulted in efforts to remediate these waste sites. To provide support to analytical measurements of hexavalent chromium, a candidate National Institute of Standards and Technology (NIST) Standard Reference Material® (SRM 2701), having a hexavalent chromium content of approximately 500 mg kg−1, has been developed using material collected from a waste site in Hudson County, New Jersey, USA. The collection, processing, preparation and preliminary physico–chemical characterization of the material are discussed. A two-phase multi-laboratory testing study was carried out to provide data on material homogeneity and to assess the stability of the material over the duration of the study. The study was designed to incorporate several United States Environmental Protection Agency (USEPA) determinative methods for hexavalent chromium, including Method 6800 which is based on speciated isotope dilution mass spectrometry (SIDMS), an approach which can account for chromium species inter-conversion during the extraction and measurement sequence.
Trace elemental speciation analysis is assuming more critical importance in nutritional and toxicological assessments, and despite the necessity to quantitatively differentiate elemental species in environmental and clinical samples, there are a limited number of reference materials suitable for this purpose. A whole blood certified reference material, SRM 955c Toxic Elements in Caprine Blood was developed for the determination of toxic metals in whole blood including mercury. The certification of methylmercury, ethylmercury, and inorganic mercury was carried out by triple spike speciated isotope dilution inductively coupled plasma mass spectrometry (TS-SID-GC/ICP-MS) and represents the first whole blood material certified for three mercury species. The certified values (±expanded uncertainty) of methylmercury, ethylmercury, inorganic mercury and total mercury in SRM 955c are 4.5 ± 1.0 µg L−1, 5.1 ± 0.5 µg L−1, 9.0 ± 1.3 µg L−1, and 17.8 ± 1.6 µg L−1 respectively.
SRM 2569 Lead Paint Films for Children's Products is a new Standard Reference Material (SRM) developed for use primarily with X‐ray fluorescence spectrometry (XRF) instrumentation. It consists of three paint coatings, with nominally 0, 90, and 300 mg/kg of Pb added, on polyester substrates. The levels of Pb are appropriate for use when validating test methods intended for testing product compliance with the Consumer Product Safety Improvement Act. The Pb mass fraction, mass Pb per unit area, paint density, and paint thickness are all characterized to make these materials useful to users of different XRF instrumentation. These parameters are consistent with one another and can be used to demonstrate mathematical conversions between units of mass fraction and mass per unit area. The assigned values for these parameters were obtained through direct determinations using instrumental methods and via calculations using measured values for paint ingredients, paint composition, and physical properties. The paints are highly homogeneous among units, although within units, some localized areas enriched in Pb can be observed using microbeam XRF instrumentation. For this reason, SRM 2569 is not recommended for use with measured areas smaller than 1 mm diameter. The development of SRM 2569 is a good case study for the use of multiple, interrelated parameters and test methods to demonstrate the comparability of values derived from a variety of measurement processes. Published 2012. This article is a US Government work and is in the public domain in the USA.
Abstract A joint U.S. Environmental Protection Agency (U.S. EPA)—AOAC interlaboratory method validation study was conducted on U.S. EPA method 200.8, Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma–Mass Spectrometry. The purpose of the study was to determine and compare the mean recovery and precision of the inductively coupled plasma–mass spectrometry (ICP–MS) analyses for 20 trace elements in reagent water, drinking water, and groundwater. The formal study was based on Youden’s nonreplicate plan for collaborative tests of analytical methods. The test waters were spiked with the 20 trace elements at 6 concentration levels in the 0.8–200 μg/L range, prepared as 3 Youden pairs. Thirteen collaborators spiked 100 mL aliquots of the test waters, acidified them with 1 mL concentrated HNO3 and 0.5 mL concentrated HCl, reduced the volume to 20 mL by heating in an open beaker at 85°C, refluxed them for 30 min at 95°C, and diluted them to 50 mL. After centrifuging or settling the samples, a 20 mL portion of the supernatant was diluted to 50 mL and analyzed by ICP–MS. Related experiments evaluated the method performance in wastewater and wastewater digestate at a single concentration pair, and an alternative nitric acid digestion procedure. Mean recoveries for reagent water, drinking water, and groundwater were generally 95–105% with between-laboratory relative standard deviations about 4–8%. The method also worked well with wastewaters and digestate, with between-laboratory relative standard deviations averaging 8% and recoveries averaging 100%. Recoveries of silver, however, were low in all matrixes at concentrations over 100 μg/L. The nitric acid digestion procedure was comparable in accuracy and precision to the mixed-acid digestion in U.S. EPA method 200.8. The method was adopted first action by AOAC INTERNATIONAL.
We present here a new environmental measurement method for the rapid extraction and accurate quantification of Cr(VI) in solid samples. The quantitative extraction of Cr(VI) is achieved in 10 minutes by means of focused microwave assisted extraction using 50 mmol/L Ethylendiamintetraacetic acid (EDTA) at pH 10 as extractant. In addition, it enables the separation of Cr species by anion exchange chromatography using a mobile phase which is a 1:10 dilution of the extracting solution. Thus, neutralization or acidification steps which are prone to cause interconversion of Cr species are not needed. Another benefit of using EDTA is that it allows to measure Cr(III)-EDTA complex and Cr(VI) simultaneously in an alkaline extraction solution. The application of a 10 minutes focused microwave assisted extraction (5 min at 90 °C plus 5 min at 110 °C) has been shown to quantitatively extract all forms of hexavalent chromium from the standard reference materials (SRM) candidate NIST 2700 and NIST 2701. A double spike isotope dilution mass spectrometry (IDMS) procedure was employed to study chromium interconversion reactions. It was observed that the formation of a Cr(III)-EDTA complex avoided Cr(III) oxidation for these two reference materials. Thus, the use of a double spiking strategy for quantification is not required and a single spike IDMS procedure using isotopically enriched Cr(VI) provided accurate results.