Assessment of Concentrations of Four Phenothiazine Antipsychotics in Serum and Whole Blood Using Different Diatomaceous Earth-based Solid-phase Columns: A Comparative Analysis

This study attempted to determine the phenothiazine antipsychotics concentration in serum and whole blood samples using various diatomaceous earth-based solid-phase columns and elution solvents and subsequently evaluate their efficiency. Phenothiazine antipsychotics concentrations of 5–2000 ng/mL were extracted from serum and whole blood using each column. All compounds were analyzed using liquid chromatography–tandem mass spectrometry. Phenothiazine antipsychotics extraction in serum and whole blood using diatomaceous earth-based solid-phase columns seemed to have an affinity with the elution solvent.