interference of salicylic acid in the blank sample

[gxch43]

Does anyone here have the experience of developing the LC/MS/MS method for simultaneous determination of aspirin and salicylic acid?
there are always the interference of salicylic acid in the blank plasma,
we have spend much time and used all kinds of methods in oder to solved this problem, but it is still there
we have searched some related articles, no significant interference was reported except one article.

who can help me? your reply will be appreciated.

[krickos]

Hi

Is it real plasma or artificial?

Salicylic acid can be used as a food preservative and antiseptic in toothpaste so can be present in real plasma I suppose.

[dr_Pyrex]

Please read this:
http://www.associatedcontent.com/articl ... tml?cat=58

we have some experience with animal tissues and SA (we use lc/mc/mc i residue analysis). We find SA every time (at the low levels, below ppb).

[gxch43]

Thank you for the replies, it is real monkey plasma,
dr_Pyrex, thank you for your share, it is very useful for me, but Do you find the SA below the ppb(ng/ml) level?
we always found the SA at ppb(ng/ml) level, thank you for your help!

[dr_Pyrex]

Maybe I was not precise: we have obtain results for SA in the range 0.01-0.5 ug/kg (ng/g) (in the muscles)