The CCQM-K34.2016.1 was organized as a subsequent key comparison of CCQM-K34.2016 assay of potassium hydrogen phthalate to demonstrate the improved capability of the laboratories which did not perform well in the original CCQM-K34.2016. The key comparisons were organized jointly by the working groups of inorganic analysis and electrochemistry analysis. National Institute of Metrology P. R. China (NIM) acted as the coordinating laboratory, and NIM and SMU (Slovak Institute of Metrology) served as linking laboratories to link to the CCQM-K34.2016 key comparison reference value (KCRV). CENAM, NIST and VNIIFTRI registered in K34.2016.1, however, VNIIFTRI gave up participating in the comparison due to failure to get the samples through the customs clearance in Russia. All participants used constant current coulometry for measurement, and improved capabilities were demonstrated.

The scope is same as in CCQM-K34.2016. The comparison tested the capabilities and methods used for assay of high purity materials. Good result indicates good performance in assaying the purity （amount content）of solid weak acids.

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).