Quality of the collection

Quality Assurance of 10 mM solutions stored at Compound Center

Description

The compound collection owned by Chemistry Biology Consortium Sweden consists of approximately 350 000 compounds and is constantly growing. The compound collection is kept in microtubes or on microtiter plates as 10mM DMSO solution. The tubes are stored in an automated compound freezer, Liconic STT3K (KIWI), at -20°C with a humidity control of < 20% and the microtiter plates are stored in lab freezers at -20°C. The target of the procedure is to maintain a quality limited to a range where 90% of CBCS compound collection has a purity > 85% and the identity confirmed (expected mass found). Compounds below purity threshold or lacking detectable mass peaks are flagged as suspects and subjected to further analysis (e.g., alternative LC‑MS methods or NMR).

Procedures

Selection is aimed at producing a representative array of structures with a broad dispersion regarding their time of storage. The compounds are chosen in a random order in terms of structure and lifetime to uphold statistical standard.

A large enough sampling (> 1000) is initially needed to be able to determine the quality of the compound collection with statistical certainty. After enough analysis has been performed and data results been analyzed, the variance and standard deviation is calculated which able us to obtain a confidence interval of 95 %. Calculations are made with the aim to confirm that there is a 95 % probability that the purity of the compound collection is > 85%.

Quality analyses are then performed regularly with a minimum of 500 compounds per year.

To read about the analysis:

Statistics

The monitoring of the purity values is visualized in a confidence interval of 95%.

For the calculation of the confidence interval all the IP results from the last 10 years are used. For compounds with multiple results during the 10-year period only the latest result is included. Compounds that do not have value for purity, due to the method not being optimal for the compound, are not included in the statistics.

Actions and Future Aim

All results will be saved in the CBCS database Scarab. All raw data will archived.

Compounds that meet the quality requirements will not undergo any further actions.

Compounds with ambiguous results or purity between 50-85% will be set as Suspects and will continue to be used awaiting further analysis, e.g. alternative LC-MS method or NMR.

The DMSO-solutions of compounds with purity below 50% or with the wrong identity will be placed in “quarantine” and will not be used for by Compound Center for deliveries. The compound solutions will eventually be removed from the collection, if possible, and the solutions will be remade from solids if available or resynthesized if interesting.

The aim is to constantly improve the quality of the collection by removing not approved compounds. The consequence of the efforts will be a collection where quality will increase in time instead of degrading.