The aim of this study was to demonstrate the robustness and reproducibility of the Thermo Scientific TSQ Vantage for highly sensitive bioanalysis of paroxetine in rat plasma. Paroxetine was spiked into rat plasma and was injected as a batch consisting of blanks, calibration standards, and QCs. The total batch consisted of 1000 plasma samples with the intent of overlaying the calibration curves (five), which were run every 200 injections as a measure of reproducibility and ion source robustness.