Complex formulations often pose persistent challenges to nitrosamine research due to their complicated matrices and low limits for nitrosamine impurities. I will continue discussions related to nitrosamine research under this topic, and welcome everyone to leave comments.
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I consistently told my team that we needed to always consider the need for SPE cleanup. I think I also saw an article using super critical CO2. I would always be a little skeptical of that route. It seems to always have its theoretical proponents more than use cases.
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Depending on the structure of the nitrosamine, the well‑known QuEChERS method from pesticide analysis can also work surprisingly well. Essentially, it’s just a liquid–liquid partition between acetonitrile and water after the addition of salts. As a result, many highly polar matrix components are removed. In general, liquid–liquid extraction is a very effective way to reduce matrix load. However, I try to develop methods that avoid the use of “bad” solvents like dichloromethane whenever possible.
Dispersive SPE (for example with C18) has also worked very well for some nitrosamines. Also its easier to perform than normal SPE.
Ultimately, the most effective approach is often to optimize sensitivity. For example by using a different mobile‑phase additive and thereby detecting a more favorable adduct. (M+H / M+Na / M+NH4 / etc.) This allows you to dilute the sample to the point where the matrix no longer has any significant impact. Of course, I’m aware that this is not always possible.
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