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- Boden (2)
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Validation of a European standard for the determination of hexavalent chromium in solid material
(2007)
A European standard for the determination of Cr(VI) in solid material has been elaborated in the framework of an international co-operation and finally validated in the course of an interlaboratory comparison. The procedure is based on the alkaline digestion prescribed by EPA method 3060A followed by ion chromatography and determines an operationally defined content of Cr(VI), including water-soluble and insoluble chromates. A preliminary robustness study was carried out in order to compare different extraction methodologies and to study the equivalency of different analytical methods for the determination of Cr(VI) in alkaline extracts of soil and waste materials. During an interlaboratory validation trial with 19 European laboratories a set of 4 samples (2 soil and 2 waste samples) was analysed to determine performance characteristics for different combinations of digestion and detection methods. With the procedures prescribed by the new European standard (EN 15192) acceptable results were obtained for both soil samples and one of the waste samples (sludge). However, for the second waste sample (fly ash) a large deviation in analytical results was observed. This indicates that particularly for waste materials a possible occurrence of strong matrix effects has to be considered and supplementary quality control data are needed in order to assess the validity of analytical results. The accuracy of the determination of Cr(VI) in solid matrices remains a challenging field in terms of maximum extraction efficiency and minimum species interconversion.
An efficient solid phase extraction (SPE) method using bis-(2-ethylhexyl)-phosphate (HDEHP) coated reverse phase C18 support has been developed for the pre-concentration of Gadolinium (Gd) and Gd contrast agents widely used in magnetic resonance imaging (MRI). Enrichment of Gd in the ionic form has been compared with strong cation exchange material Chromabond SA (SCX), weak ion exchange material Chelex-100 and also with lanthanide specific HDEHP modified reverse phase C18. The determination of Gd and its complexes after enrichment were performed using inductively coupled plasma mass spectrometry (ICP-MS) and on the basis of 158Gd. Among the three SPE materials, HDEHP coated reverse phase C18 SPE has been found to be most efficient, yielding a hundredfold Gd enrichment with > 95% recovery for linear and cyclic contrast agents like Gd-DTPA (Magnevist), Gd-DOTA (Dotarem), Gd-BOPTA (Multihance), and Gd-BT-DO3A (Gadovist). The developed SPE method has been successfully applied to the surface water and waste water samples originated from different places in Berlin, Germany. The results were in good agreement with the results obtained with direct measurement with ICP-MS. The developed pre-concentration method can be efficiently used for the determination of trace levels of gadolinium in the environment even with less sensitive analytical techniques.
The resource-saving utilisation of recovered
waste wood is a matter of growing concern. In several
European countries, this utilisation is governed by regulations
and is dependent on the contents of certain trace
elements and organic compounds. Thus, for decisionmaking
with respect to waste wood management (recycling
or combustion), reliable analytical data are needed and, due
to their great economic and environmental impact, must be
assured by appropriate quality control. To support the
improvement in quality assurance in waste wood analysis,
for the first time, a wood reference material was certified
for its mass fractions of arsenic, cadmium, chromium,
copper, lead, mercury, and pentachlorophenol (PCP).
These analytes were selected because they represent typical
constituents of wood preservatives most widely used in the
past. Material preparation and testing of homogeneity and
stability were carried out by BAM Federal Institute for
Materials Research and Testing. The certification measurements
were performed involving selected laboratories
with documented expertise in the field of waste wood
analysis. The certified values and their corresponding
uncertainties were assigned in full compliance with the
requirements of ISO Guide 35. The certified mass fractions
and their expanded uncertainties (k/i> = 2) are as follows:
(3.1 ± 0.5) mg/kg for As, (3.02 ± 0.24) mg/kg for Cd,
(36.4 ± 2.6) mg/kg for Cr, (22.9 ± 1.7) mg/kg for Cu,
(0.60 ± 0.14) mg/kg for Hg, (39 ± 4) mg/kg for Pb, and
(7.9 ± 0.6) mg/kg for PCP. The certified material is
available as European Reference Material ERM®-CD100.
Die Normung von Analyseverfahren ermöglicht, dass Parameter unter standardisierten Bedingungen qualitätsgesichert ermittelt werden können. Insbesondere dann, wenn Verfahren in gesetzliche Regelwerke einfließen, ist es notwendig, dass die Ergebnisse sicher und vergleichbar sind und der Aufwand im Vollzug vertretbar ist. Derzeit werden viele Parameter in verschiedenen Verordnungen nach unterschiedlichen genormten Verfahren analysiert, was die Überwachungsarbeit erschwert und zudem unnötig teurer macht. Aus diesem Grund wir eine sogenannte horizontale Normung angestrebt, bei der geeignete Analyseverfahren auch Matrices-übergreifend genormt und anschließend EU-weit zitiert werden können. Grundvoraussetzung für die Verabschiedung als Norm ist die Validierung der Verfahren. Bereits vor einigen Jahren erteilte die EU ein Mandat an CEN (Europäisches Komitee zur Normung), um umweltrelevante Parameter Matrices-übergreifend zu validieren. Allerdings konnten nicht alle für diverse Verordnungsnovellen (z.B. Klärschlammverordnung) wichtigen Parameter im Rahmen dieses Projekts validiert werden. Aus diesem Grund wurde das aktuelle Vorhaben in den Umweltforschungsplan des BMUB aufgenommen und von der BAM durchgeführt. Im Forschungsvorhaben konnten im Bereich der anorganischen Parameter die CEN/TS 16170 (Elemente mit ICP-OES), CEN/TS 16171 (Elemente mit ICP-MS) und CEN/TS 16175-2 (Quecksilber mit CV-AFS) sowie im Bereich der organischen Parameter die CEN/TS 16181 (PAK mit HPLC und GC), die CEN/TS 16167 (PCB mit GC-MS und GC-ECD) und die CEN/TS 16190 (Dioxine, Furane und dl-PCB mit HR-GC-MS) für die Analyse von Klärschlamm, behandeltem Bioabfall und Boden erfolgreich validiert werden. Die validierten Verfahren stehen nun kurz vor der Verabschiedung als EN (Europäische Norm).