In September 2022, the Tobacco and Tobacco Products Analysis (TTPA) Sub-Group initiated the fourth study to assess the stability of the four CORESTA Reference Products (CRPs) manufactured in 2016, and to provide repeatability (r) and reproducibility (R) results and z-scores to support laboratory accreditation. Sixteen laboratories participated in the study. The participating laboratories reported the levels of nicotine, pH, moisture (oven volatiles), and tobacco specific nitrosamines (TSNAs) in the CRPs using CORESTA Recommended Methods (CRMs).

The results from this 2023 stability analysis generally compared well to the results from the analyses done in 2016, 2019, and 2021. The only statistically significant product trends differences from the 2016 and 2019 results were slight increases in moisture for CRP3.1 and a small pH drop in CRP1.1.  These results are consistent with the trends seen with the CRPs produced in 2009.

The TTPA recommends that the stability of the 2016 CRPs continue to be monitored on a biennial basis.