The importance of optimal extraction to insure the reliable MS-based assays of endogenous compounds

Abstract

Specificity is a challenge for accurate determination of the concentration of endogenous compounds in biological matrices which can be affected by the sample preparation and the choice of the MRM transition of the LCMS/MS. Therefore, the sample preparation procedure should be optimized for each endogenous compound. In the meantime, during the method development stage, the quantitation should be compared or the ion ratio of two MRM transitions should be monitored, not only with qualifiers. The optimal extraction not only reduces the baseline but also limits the potential interferences. Monitoring of the ion ratio or quantitation using two different MRM transitions can ensure the specificity, thus leading to a more reliable measurement of endogenous compounds. These strategies are very important for the accurate quantitation of endogenous compounds either with LLE or SPE.