Fatty acids (FA) are substances, which are common contaminations in LC-MS systems and they “like to remain” in the system. FA are part of the most biological samples and can be easily broguht into the system. e.g., solvent bottles.
Even after a successful cleaning, systems get easily contaminated as FA are part of the most samples.
Signals and noise on MRMs of fattyacids
- The noise level of at least FA(12:0) to FA(14:0) or sometimes to FA(18:0) may be elevated and the analytical classification of these metabolites is “invalid”.
- This may also apply for DiCa(12:0) and DiCa(14:0).

Fatty acids
can be removed from LC-MS systems by applying intense cleaning procedures.
However, when analyzing biological samples, the system will be “contaminated”
again with fatty acids.