Key Comparison CCQM-K73.2018 Amount Content of H⁺ in Hydrochloric Acid (0.1 mol·kg⁻¹)

Main text The CCQM key comparison K73.2018 is a follow-up comparison of CCQM-K73. It was performed to demonstrate the capability of the participating institutes to measure the amount content of H+ in hydrochloric acid of 0.1 mol·kg−1 molality. 16 NMIs participated in this comparison. The comparison was coordinated by PTB. The sample showed a slight but significant instability by loss of water of around 0.11 μmol kg−1d−1 corresponding to 0.02 % over the measurement period. Therefore, the results were corrected for this instability. The results of this key comparison show good equivalence between the majority of participants. The equivalence is significantly better compared to the first comparison CCQM-K73. 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).