title: Comparison of conventional liquid chromatography-tandem mass spectrometry versus microflow liquid chromatography-tandem mass spectrometry within the framework of full method validation for simultaneous quantification of 40 antidepressants and neuroleptics in whole blood.
abstract: Microflow liquid chromatography (MFLC) coupled to mass spectrometry (MS) is claimed to improve analysis throughput, reduce matrix effects and lower mobile phase consumption. This statement was checked within the framework of method validation of a multi-analyte procedure in clinical and forensic toxicology employing MFLC-MS/MS and conventional LC-MS/MS. 200 μL whole blood were spiked with 50 μL internal standard mixture and extracted by protein precipitation. The concentrated extract was separated into two vials. One was analyzed using a Thermo Fisher Ultimate liquid chromatography system coupled to an ABSciex 5500 QTrap mass spectrometer (LC-MS/MS) and one by an ABSciex Eksigent Microflow LC system coupled to an ABSciex 4500 linear ion trap quadrupole MS (MFLC-MS/MS). Both methods were fully validated and compared in terms of selectivity, stability, limits, calibration model, recovery (RE), matrix effects (ME), bias, imprecision and beta tolerance interval for 40 antidepressants and neuroleptics including 9 metabolites. Both methods had comparable LODs, LOQs and calibration models with some exceptions. The MFLC system showed slightly higher coefficients of variation (CVs) in the RE experiments. ME were reproducible in both systems but with lower CVs in the conventional LC system. Acceptance criteria for imprecision and bias were fulfilled for 32 analytes on the LC and for 28 analytes on the MFLC system. Beta tolerance intervals indicated better reproducibility in terms of narrower intervals for the conventional LC system. The advantages of the MFLC system were low mobile phase consumption, short run time, and better peak separation. The systems were comparable in terms of peak interference, LOD, ME, bias and imprecision. The advantages of the conventional LC system were more data points per peak, linear calibration models, stable retention times and better beta tolerance intervals. Due to higher robustness, the conventional LC system was finally chosen for routine application in forensic toxicology.
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland. Electronic address: andrea.steuer@irm.uzh.ch.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Steuer
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Poetzsch
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Koenig
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Eva
authors.initials: E
authors.lastname: Tingelhoff
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Sandra N
authors.initials: SN
authors.lastname: Staeheli
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Andreas T
authors.initials: AT
authors.lastname: Roemmelt
authors.affiliation: Department of Forensic Pharmacology & Toxicology, Institute of Forensic Medicine, University of Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kraemer
mesh_terms: D000928:Antidepressive Agents / Q000097:blood*; D014150:Antipsychotic Agents / Q000097:blood*; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods* / Q000592:standards; D053593:Forensic Toxicology / Q000379:methods; D006801:Humans; D057230:Limit of Detection; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods* / Q000592:standards
chemical_list: D000928:Antidepressive Agents; D014150:Antipsychotic Agents
keywords: Antidepressants; Comparison; Microflow LC–MS/MS; Neuroleptics; Validation