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The need for quality assessment of anthropogenic impact on environmental pollution is increasing due to discharge from various industries, the use of chemicals in agriculture and the consumption of fossil fuels. Diminishing resources such as natural waters used for the cultivation of agricultural products, plant and animal habitats are under severe pollution pressure and are at constant risk. Several parameters, such as Pb, Cd, Ni, Hg were listed by Water Framework Directive in Directive(2008/105/EC) in the priority substances. Cadmium and Hg were identified as priority hazardous substances whereas As is an important contaminant for its potential toxicological and carcinogenic effects. An inter-comparison study is organised in EURAMET TC-MC in order to demonstrate the capability participants for measuring five elements in river water. The participants carried out measurements for analytes: Pb, Cd, Ni and As as mandatory elements, and Se as an optional one. Participants were asked to perform the measurements with respect to the protocol provided. 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 https://www.bipm.org/kcdb/.
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).
The CCQM-K88 key comparison was organized by the Inorganic Analysis Working Group of CCQM to test the abilities of the national metrology institutes to measure the mass fraction of lead in lead-free solder containing silver and copper. National Metrology Institute of Japan (NMIJ), National Institute of Metrology of China (NIM) and Korea Research Institute of Standards and Science (KRISS) acted as the coordinating laboratories. The participants used different measurement methods, though most of them used inductively coupled plasma optical emission spectrometry (ICP-OES) or isotope-dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Accounting for relative expanded uncertainty, comparability of measurement results was successfully demonstrated by the participating NMIs for the measurement of the mass fraction of lead in lead-free solder at the level of 200 mg/kg.
It is expected that metals at mass fractions greater than approximately 100 mg/kg in lead-free solder containing silver and copper 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.
A two-step separation procedure for the quantification of Pd and Pt in automotive exhaust emissions using isotope dilution mass spectrometry was established using a combination of cation and anion exchange chemistry. AG 50W-X12 was used as cation exchange resin and DGA as weakly basic anion exchange resin. This procedure enabled the effective separation of Pd and Pt from the matrix and from interfering elements. Additionally Pd and Pt were collected in separate chromatographic fractions, which increased the precision of the isotope ratio determination by separate measurements using single collector sector field ICPMS. The analytical procedure was validated by analysing the synthetically prepared samples and the certified reference materials BCR-723 (road dust) and IAEA-450 (algae). For the SI-traceable results complete uncertainty budgets were calculated yielding relatively expanded uncertainties (k = 2) of ≈1% for analyte masses in the ng range. Procedure blanks of 55 pg Pd and 3 pg Pt were obtained. The detection limits were calculated as 12 pg for Pd and 7 pg for Pt. Additionally, Pd and Pt blank levels of different filter materials are presented as well as the first results for automotive exhaust particles collected on cellulose filters.
Isotope dilution mass spectrometry often is applied for the quantification of platinum group elements in environmental and geological samples. In most cases, however, certified spike solutions offering complete uncertainty statements and SI-traceability are missing. This report describes the production and certification of two isotope reference materials, ERM-AE140 and ERM-AE141, serving as calibrated spike solutions for IDMS based quantification of Pd and Pt, respectively. Both materials were produced by dissolving highly enriched isotopes 106Pd and 194Pt and determining the mass fraction of 106Pd and 194Pt in the final solution by reverse IDMS. Two independent back-spikes were produced for each material from high purity Pd and Pt. Characterization measurements were carried out by MC-ICPMS. For ERM-AE140 the certified mass fractions are w(106Pd) = 20.24(5) mg/kg and w(Pd) = 20.54(5) mg/kg. For ERM-AE141 the certified mass fractions are w(194Pt) = 18.18(11) mg/kg and w(Pt) = 19.90(12) mg/kg. These values are traceable to the International System of Units (SI) in the shortest possible way.
CCQM-K143 is a key comparison that assesses participants’ ability to prepare single element calibration solutions. Preparing calibration solutions properly is the cornerstone of establishing a traceability link to the International System of Units (SI), and therefore should be tested in order to confirm the validity of CCQM comparisons of more complex materials. CCQM-K143 consisted of participants each preparing a single copper calibration solution at 10 g/kg copper mass fraction and shipping 10 bottled aliquots of that solution to the coordinating laboratory, the National Institute of Standards and Technology (NIST). The masses and mass fraction for the prepared solutions were documented with the submitted samples.
The solutions prepared by all participants were measured at NIST by high performance inductively coupled plasma optical emission spectroscopy (HP-ICP-OES). The intensity measurements for copper were not mapped onto values of mass fraction via calibration. Instead, ratios were computed between the measurements for copper and simultaneous measurements for manganese, the internal standard, and all subsequent data reductions, including the computation of the KCRV and the degrees of equivalence, were based on these ratios. Other than for two participants whose measurement results appeared to suffer
from calculation or preparation errors, all unilateral degrees of equivalence showed that the measured values did not differ significantly from the KCRV. These results were confirmed by a second set of ICP-OES measurements performed by the Physikalisch-Technische Bundesanstalt (PTB). CCQM-K143 showed that participants are capable of preparing calibration solutions starting from high purity, assayed copper metal.
Similar steps are involved when preparing solutions for other elements, so it seems safe to infer that similar capabilities should prevail when preparing many different, single-element solutions.
Lead (Pb) isotope amount ratios are commonly used in applications ranging from archaeology and forensic sciences to terrestrial and extra-terrestrial geochemistry. Despite their utility and frequency of use, only three certified isotope amount ratio reference materials are currently available for Pb: NIST SRMs 981, 982 and 983. Because SRM 981 has a natural Pb isotopic composition, it is mainly used for correcting instrumental mass discrimination or fractionation. This means that, at present, there are no other certified isotope reference materials with natural Pb isotopic composition that could be used for validating or verifying an analytical procedure involving the measurement of Pb isotope amount ratios.
To fill this gap, two new reference materials, both certified for their Pb isotopic composition, have been produced together with a complete uncertainty assessment. These new reference materials offer SI traceability and an independent means of validating or verifying analytical procedures used to produce Pb isotope amount ratio measurements.
ERM-EB400 is a bronze material containing a nominal Pb mass fraction of 45 mg/kg. ERM-AE142 is a high purity solution of Pb with a nominal mass fraction of 100 mg/kg. Both materials have been specifically produced to assist analysts in verifying or validating their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM-EB400), the other does not (ERM-AE142). Details on the certification of these isotope reference materials are provided in this report.