Determination of Aripiprazole, Blonanserin, and Their Metabolites in Human Urine by Automated μSPE–LC–MS/MS

In this study, an automated micro-solid-phase extraction (μSPE)–liquid chromatography–tandem mass spectrometric (LC–MS/MS) method was developed and validated to determine aripiprazole, dehydroaripiprazole, blonanserin, and N-desmethyl blonanserin in human urine. An instrument top sample preparation cartridge was implemented to enhance analyte sensitivity and mitigate the matrix effects from urine samples. LC–MS/MS analysis employed a multiple-reaction monitoring mode, with analyte separation achieved using a Capcell Pak C18 MGIII column (2.0 × 150 mm, 5 µm). The mobile phase comprised a 10 mM ammonium formate solution with 0.1% formic acid and acetonitrile. The calibration range for all analytes was 0.1–50 ng mL⁻¹, yielding correlation coefficients (r) of ≥ 0.9993 and a weighting factor of 1/x². The detection limits for all analytes were 0.03 ng mL⁻¹. Intra- and inter-day accuracy ranged from − 3.6 to 5.0% and − 4.0 to 3.3%, respectively, with precision values of ≤ 9.5% and ≤ 12.9%. This validated method was successfully applied to 107 forensic urine samples. Urinary creatinine normalization was used to adjust analyte concentrations in urine. Normalized concentrations of aripiprazole, dehydroaripiprazole, blonanserin, and N-desethyl blonanserin were detected at 0.1–185.2 (n = 86), 0.2–295.5 (n = 91), 0.1–0.7 (n = 7), and 0.2–1.6 (n = 12) ng mg⁻¹ creatinine, respectively.