Microsomal stability on a single-quad LC-MS?

Question

Is anyone performing microsomal stability on a single-quad LC-MS? I've seen papers where researchers have used both simple UV and LC-MS detection, but most contract testing labs seem to use triple-quads, LC-MS-MS. Is a MS-MS really necessary when you're just monitoring the disappearance of the parent compound? I'd like to bring microsomal stability/clearance and Caco-2 testing in-house. It would be really nice if I could use one of our existing LC-MS systems.

dawn · Accepted Answer

I would agree a good starting place is to compare the results from your CRO to your single quad for comparability. If you do so, try to keep as much the same between the two experiments (ie split your samples so they are same at your site and the CRO and try to run the same LC conditions- columns and mobile phases included). I'm assuming you have an agilent single quad and if your CRO has an agilent triple quad you can try to match the source conditions as well.

dawn · Answer

For this experiment, a triple quad run in MRM mode will offer you more sensitivity than a single quad run in SIM mode. The triple quad will also offer you additional selectivity and give you have more confidence you are quantifying the correct compound. This is because you can monitor multiple product ions of that compound (and get a ratio of one vs the other- a qualifying ion ratio) and product ions are more "unique" to a compound than just the precursor mass. Additionally, you have less likelihood with the triple quad run in MRM mode, that the matrix is contributing to this signal. You could certainly use your single quad run in SIM mode to perform your experiment. However, you have to determine if it will give you the sensitivity you need. Additionally, it could be tricky with heavy matrix because you do not have as much confidence that you are quantifying "clean" signal (there could be matrix interference). You will need to be more mindful of having a good LC separation and a good sample prep cleanup protocol.

Microsomal stability on a single-quad LC-MS?

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