| Zugriffsnummer | 21729 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Final report on CCQM-K9.2: Subsequent key comparison on pH determination of phosphate buffer by Harned cell measurements |
| Autor(in); Institution |
Spitzer, Petra; 3.1, Metrologie in der Chemie, PTB-Braunschweig
Giera, Janine; 3.1, Metrologie in der Chemie, PTB-Braunschweig
Fraga, Isabel C.; INMETRO, Duque de Caxias, BRAZIL
Tønnes Jakobsen, Pia; Danish Institute of Fundamental Metrology, Lyngby, DENMARK
Jensen, Hans D.; Danish Institute of Fundamental Metrology, Lyngby, DENMARK
Hyllested, Peter; Danish Institute of Fundamental Metrology, Lyngby, Denmark
Karpov, Oleg; National Research Institute for Physical-Technical and Radio-technical Measurements (VNIIFTRI), Moscow Region, RUSSIA
Kutovoy, Viatcheslav; National Research Institute for Physical-Technical and Radio-technical Measurements (VNIIFTRI), Moscow Region, RUSSIA
Nakamura, Susumu; National Metrology Institute of Japan (NMIJ), Tsukuba, JAPAN
Vospelova, Alena; Czech Metrology Institute, Brno, CZECH REPUBLIC
Zvezdina, Valentina; National Research Institute for Physical-Technical and Radio-technical Measurements (VNIIFTRI), Moscow Region, RUSSIA
|
| Quelle/Jahr | Metrologia: 45 (2008), Tech. Suppl., 20 S. |
| Artikelnummer | 08006 |
| Availability | [online only] |
| ISSN | 0026-1394 |
| DOI | |
| Verlag | Bristol [u.a.]: IOP |
| Zusammenfassung | CCQM-K9.2 was performed supplementary to the key comparison CCQM-K9 on the pH determination of a phosphate buffer with nominal pH ≈ 6.9 (at 25 °C). The sample composition was very similar in both comparisons. Only the source of the starting material used for sample preparation was different. The comparison was restricted to the use of the primary method for pH (Harned cell measurement) as defined in the IUPAC Recommendations. The measurement temperatures were 15 °C, 25 °C, 37 °C. CCQM-K9.2, CCQM-K.9 and the first supplementary comparison CCQM-K9.1 are activities of the Electrochemical Working Group (EAWG) of the CCQM. All three comparisons were coordinated by the PTB, Germany. The Danish Primary Laboratory (DPL) successfully took part in the CCQM-K9. Meanwhile the primary set-up for pH in Denmark moved from DPL affiliated to Radiometer Medical to DFM, Denmark. The subsequent comparison allows assessing the degree of equivalence for the measurement of pH at DFM after the move. Due to the interest of other laboratories in demonstrating their progress in pH measurements on the primary level the CCQM-K9.2 supplementary comparison was extended to other participants than DFM, namely NMIJ, VNIIFTRI, INMETRO and CMI. The reported quantity for CCQM-K9.2 was not the pH of the sample but the acidity function at zero chloride molality (see chapter 12). To calculate the pH value from the acidity function it is necessary to know the ionic strength of the sample buffer solution, which was undisclosed by the coordinator. With the exception of the Czech Metrology Institute, CMI, good agreement in the determined acidity function is found between the participants. The results reported by DFM and by PTB agree within their measurement uncertainty at all measurement temperatures. |
Zitierung
Spitzer, P., Giera, J., Fraga, I. C., Tønnes Jakobsen, P., Jensen, H. D., Hyllested, P., Karpov, O., Kutovoy, V., Nakamura, S., Vospelova, A., & Zvezdina, V. (2008). Final report on CCQM-K9.2: Subsequent key comparison on pH determination of phosphate buffer by Harned cell measurements. Metrologia, 45(Tech. Suppl.), 20 S. https://doi.org/10.1088/0026-1394/45/1a/08006