No abstract

The determination of the mass fractions of bromide, sulfate, and lead as well as the isotopic composition of the lead (expressed as the molar mass and the amount fractions of all four stable lead isotopes) in an aqueous solution of sodium chloride with a mass fraction of 0.15 g/g was the subject of this comparison. Even though the mass fractions ranged from 3 μg/g (bromide) to 50 ng/g (lead), almost all results reported agreed with the according KCRVs. 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).

In this key comparison anion calibration solutions of nitrate and nitrite were investigated. The mass fractions of the anions in both solutions were about 1 g/kg. For the nitrate comparison 8 participants provided results; 3 analytical techniques were used: ion chromatography, capillary electrophoresis and coulometry after ion exchange. The nitrite amount content was determined by 7 participants using one of the following 3 techniques: ion chromatography, titrimetry and capillary electrophoresis.The following institutes participated in this key comparison: INTI (Argentina), KRISS (Korea), LNE (France), NIM (Pepole's Republic of China), NIST (USA), NMIJ (Japan), SMU (Slovakia) and VNIIM (Russia).The variability (RSD) of the results is about 0.75% for both the nitrite and the nitrate solutions. Compared to the key comparison CCQM-K29 the results of CCQM-K59 were significantly worse. This is in part due to the measurement methods used, possibly also due to the standards used by the institutes.A pilot study (P89) was performed in parallel on the same calibration solutions used in this K59 comparison study by laboratories preferring to participate in the pilot study and on a seawater sample containing about 0.1 mg/kg nitrite and 1 mg/kg nitrate. The results of the pilot study are reported separately.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 (MRA).

Main text Electrolytic conductivity in aqueous solutions is a common electrochemical measurement technique in industry. Since it is sensitive to the amount content of dissolved ions in a solution, a limiting value for conductivity is a clear and simple quality criterium for the ionic purity of pure water, roughly ranging from 0.055 μS/cm to 150 μS/cm at 25 °C. International regulations are becoming stricter with regards to metrological traceability to guarantee compliance of measurement results with relevant standards. Consequently, the NMIs active in this area have been facing an increasing request for the calibration of respective conductivity sensors and for adequate CRMs over the past years. A first, regional comparison has been conducted in 2013/14 (EURAMET 1271). Since an increasing number of NMIs, also from other regions, seek providing respective services and establishing CMCs, EURAMET, i.e. the Sub-Committee on Electro Analysis of TC-MC, opened a follow-up comparison to other regions in terms of a supplementary CCQM comparison (EURAMET.QM-S12). The comparison has been conducted in terms of a Round Robin scheme. A conductivity sensor has been sent around between ten participants for calibration at four conductivity levels (0.055, 0.5, 5 and 50 μS/cm at 25 °C). Basically, the measured measurement errors of the device have been compared in terms of conductivity. Additionally, the cell constants calculated from the calibration results have been compared. Apart from very few outliers, the comparison has demonstrated good equivalence of the calibration capabilities. 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).