Kristien Vercoutere

Certified reference material (CRM 414) for the quality control of trace element analysis in plankton

SummaryAnalyses of plankton are performed by a number of organisations to investigate the transfer and uptake of toxic elements along the trophic chain and to monitor the levels of contamination of different aquatic environments. In order to obtain reliable transfer functions in environmental models or to use plankton as an indicator organism for the assessment of environmental pollution, these analyses should give accurate results. As accuracy requires quality control and the application of certified reference materials (CRMs), a certification campaign has been conducted by the Community Bureau of Reference (BCR). A plankton material was collected in a freshwater pond, lyophilised, homogenised and bottled and its homogeneity and long-term stability were verified. The material (CRM 414) was analysed by a group of 15 selected laboratories having given proof of their adequate QC and using different analytical methods. The contents of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Se, V and Zn are certified. This paper presents the certification work performed.

Cr(III) and Cr(VI) speciation measurements in environmental reference materials

The production of reference materials for quality control of Cr(III) and Cr(VI) speciation in environmental samples is described. It concerns in the first place two lyophilized solutions containing Cr(III) and Cr(VI) at different concentrations, respectively representative for drinking water and filter leaching solutions, and in the second place filters loaded with welding dust. Twenty-four laboratories with experience in the field participated in an intercomparison exercise organized to validate the suitability of the reference materials and to gauge the state-of-the-art of Cr speciation throughout Europe. The outcome of this exercise is discussed.

Certification of the contents of the chromium(III) and chromium(VI) species and total chromium in a lyophilised solution (CRM 544)

The preparation is described of a batch of 1100 vials containing a lyophilised solution, with CrVI and CrIII contents as in natural or tap water and a total Cr content <50 µg l–1 following the European Community Directive 80/778/EEC, L229/20, D48 on the quality of drinking water. The homogeneity and stability studies and the analytical work performed for the certification of the contents of the CrIII and CrVI species and the total Cr content are also described. The paper contains all the results and gives the methods used to certify the measured concentrations of CrVI (22.79 µg l–1), CrIII (26.77 µg l–1) and total Cr (49.34 µg l–1) after reconstitution in 20 ml. A brief description of the preliminary feasibility study is also given.

Certified reference material (CRM 397) for the quality control of trace element analysis of human hair

SummaryAnalyses of human hair are routinely performed by a number of organisations to monitor the level of exposure of a population to toxic elements, e.g. heavy metals. To control the quality of such determinations, the Community Bureau of Reference (BCR) has produced a reference material (CRM 397) certified for its contents of Cd, Hg, Pb, Se and Zn. This material was collected in a moderately contaminated area, carefully prepared and its homogeneity and long term stability were verified. This paper presents the certification work performed.

Certified reference materials for the quality control of trace elements in plants: white clover (CRM 402)

Abstract Analyses of plants are routinely performed by a number of organizations to determine elements of nutritive importance and of potential toxicity, e.g. heavy metal. To control the quality of such determinations, the Community Bureau of Reference has produced a series of reference materials certified for a wide variety of elements which are summarized in this paper. The last plant material produced is a white clover (CRM 402), certified for its contents of As, Co, Mo and Se. This material was collected on a field with Se-rich and poorly drained soils, carefully prepared and its homogeneity and long-term stability were verified. This paper reports the certification work performed.

Certified reference materials (CRMs 398 and 399) for the quality control of major element determination in freshwater

Analyses of freshwater are routinely performed by a number of organisations to monitor the levels of major elements. In order to improve and control the quality of such determinations, the Community Bureau of Reference (BCR) has organised a certification campaign to produce two reference materials (CRM 398, low element content and CRM 399, high element content) certified for their contents of Al, Ca, Cl, Fe, Mg, Mn, K, Na, P and S. These materials were carefully prepared (addition of the elements mentioned in the form of ammonium salts or nitrates to silica free deionised water) and their homogeneity and long term stability were verified. This paper presents the certification work performed.

Certified reference materials of soils and sewage sludges for the quality control of trace element environmental monitoring

Abstract For the wide variety of soil/sludge matrices encountered in analytical practice, a range of CRMs should be available to verify the analytical quality control of any determination carried out, using samples which should be as similar as possible to real soil and sludge samples so that the methods performance may be tested under real analytical conditions. This paper presents basic requirements for the preparation of soil and sludge CRMs for the quality control of trace element determinations (total and extractable contents, following strict extraction protocols), and gives recent examples of new certifications successfully concluded by the SM&T programme of the European Commission.