Quantification of 33 antidepressants by LC-MS/MS--comparative validation in whole blood, plasma, and serum

In the present study, a liquid chromatography-mass spectrometry (LC-MS/MS) multi-analyte approach based on a simple liquid-liquid extraction was developed for fast target screening and quantification of 33 antidepressants in whole blood, plasma, and serum. The method was validated with respect to selectivity, matrix effects, recovery, process efficiency, accuracy and precision, stabilities, and limits. In addition, cross-calibration between the three biosamples was done to assess the impact of the different matrices on the calibration. Whole blood, plasma, and serum (500 μL each) were extracted twice at pH 7.4 and at pH 10 with ether-ethyl acetate (1:1). Separation, detection, and quantification were performed using LC-MS/MS with electrospray ionization in positive mode. For accuracy and precision, full calibration was performed with ranges from subtherapeutic to toxic concentrations. The approach was sensitive and selective for 33 analytes in whole blood and 31 analytes in plasma and serum and accurate and precise for 30 of the 33 tested drugs in whole blood, 31 in plasma, and 28 in serum. Cross-calibration was successful only for 13 analytes in whole blood and 16 analytes in serum calculated over a calibration curve made in plasma, 12 analytes in whole blood and 15 analytes in plasma calculated over a calibration curve made in serum, and 10 analytes in plasma and 15 analytes in serum calculated over a calibration curve made in whole blood.