Sample Solvent- Simple Q (SillyQ almost)

[LC_addict]

Hi guys,

Very basic simple question that just randomly popped into my head. When preparing HPLC samples in solvent such as IPA or MeOH. Whats to say these are not having an effect on the Drug substance or analyte? Influencing degradation etc?
Ive never seen anyone perform any tests to confirm these are not, and when running, standards and samples 'like with like' would this even be apparent without relevant testing?

Cheers

[Don_Hilton]

IPA and MeOH are reactive molecues. So, if your analyte is an ester, aldehyde, or ketone, you can expect reacion with the solvent - and loss of analyte. While extracts which are immediately analyzed may not react sufficently quickly with the solvent to cause a problem, standards stored in these solvents could. A study of the stabiltiy of the standard in solvent is appropriate if you must use an alcohol as a solvent.

I have run into this with varuious analytes in GC methods.

[LC_addict]

IPA and MeOH are reactive molecues. So, if your analyte is an ester, aldehyde, or ketone, you can expect reacion with the solvent - and loss of analyte. While extracts which are immediately analyzed may not react sufficently quickly with the solvent to cause a problem, standards stored in these solvents could. A study of the stabiltiy of the standard in solvent is appropriate if you must use an alcohol as a solvent.

I have run into this with varuious analytes in GC methods.

I suppose in RP alcohols are very common solvents. I just presumed there to be more on this subject, althougn when samples are prepared in the same solvent as a standard does this pose such a threat?!

[Don_Hilton]

While standards and samples may be disolved in the same solvent, there are differences. Standard solutions often are kept for longer periods of time, allowing for bat things to happen for a longer period of time. And, while the solvent may be the same for standards and samles, matrix components can always make a difference.

the alcohols may cause you no problem, but it does not hurt to check. I have discoverd that it is generally what I assume to not be a problem is what bites me where it hurts.