Why my quantification standard is unstable?
Posted: Thu Jul 05, 2018 5:40 am
Hi to all,
First of all thank you for receiving me on this quite interesting forum. I think this forum will be my benchmark for my work.
I'm writing you because I'm experiencing some issues with my quantification standard I currently use to evaluate peaks eluted at hplc and analysed in ESI MS positive ion mode.
In particular, I observe a time-dependent decrease in the reserpine-peak area (my standard) and an increase in the areas of two peaks before and after the elution of the standard. The m/z of reserpine is 609.28. the m/z under that "satellite" peaks is 639.29. There is a delta of 30.01 Da corresponding, maybe, to a CH2O.
Furthermore, I observe this reserpine modification randomly, and i'd like to identify the root of this problem in order to avoid it in the next analysis.
I don't think that the problem is instrumental, but I am strongly considering that there is something that trigger some kind of reaction in my vial. Another information is that I use a mix of reserpine and another standard ( one of the various types of organic): interestingly, irganox remains stable, whilst reserpine undergoes this hellish modification.
Does anyone experienced similar issues? How did you get rid of it? Do you have any clues?
Thank you very much
First of all thank you for receiving me on this quite interesting forum. I think this forum will be my benchmark for my work.
I'm writing you because I'm experiencing some issues with my quantification standard I currently use to evaluate peaks eluted at hplc and analysed in ESI MS positive ion mode.
In particular, I observe a time-dependent decrease in the reserpine-peak area (my standard) and an increase in the areas of two peaks before and after the elution of the standard. The m/z of reserpine is 609.28. the m/z under that "satellite" peaks is 639.29. There is a delta of 30.01 Da corresponding, maybe, to a CH2O.
Furthermore, I observe this reserpine modification randomly, and i'd like to identify the root of this problem in order to avoid it in the next analysis.
I don't think that the problem is instrumental, but I am strongly considering that there is something that trigger some kind of reaction in my vial. Another information is that I use a mix of reserpine and another standard ( one of the various types of organic): interestingly, irganox remains stable, whilst reserpine undergoes this hellish modification.
Does anyone experienced similar issues? How did you get rid of it? Do you have any clues?
Thank you very much