Background
Therapeutic drug monitoring (TDM) of antidepressants is important to ensure compliance and to rule out pharmacokinetic abnormalities. Therefore, reliable
Conclusions
We have established a selective method for the quantification of antidepressants with outstanding precision using a high-resolution Orbitrap mass spectrometer. The applicability of HRMS instruments to TDM was demonstrated.
Methods
After manual protein precipitation of serum samples, further sample clean-up was achieved using a Turbo Flow column preconnected to the analytical LC column. Stable isotope-labelled counterparts of the target analytes were used as internal standards. For detection, we used a Q Exactive Focus Orbitrap mass spectrometer operating in full-scan mode. Ionization was performed in positive ESI.
Results
Accuracy, recovery, and matrix effect were acceptable for all analytes. The method demonstrated outstanding precision (within-run imprecision <4.5%, between-run imprecision <7.5%). The selectivity of the method was ensured by chromatographic separation of all isobaric compounds. Close agreement between Orbitrap and triple stage based quantification was observed in a comparison measurement of leftover patient samples. Conclusions: We have established a selective method for the quantification of antidepressants with outstanding precision using a high-resolution Orbitrap mass spectrometer. The applicability of HRMS instruments to TDM was demonstrated.