Importance of Performing Incurred Sample Stability (ISS) for having a Rugged and Accurate Omega-3 Bioanalytical Method

摘要

The stability performed on incurred samples showed an increase in EPA concentration over-time. The phenomenon was not observed in QC samples, probably because of different enzymatic activity between the fresh and the commercial plasma. These results triggered an investigation which consisted of monitoring the endogenous levels of free EPA in freshly drawn blood/plasma. The investigation demonstrated that an extended short-term storage of samples at 4°C generated a considerable increase in free EPA. The phenomenon was shown to be donor dependent. The deconjugation was totally prevented in acidified plasma with NaF/KOx as an anti-coagulant. The evaluation of the ISS along with a thorough investigation of the observed instability led to a better collection procedure and a more rugged and accurate method for the quantification of free EPA and DHA in human plasma.