title: Simultaneous determination of phosphatidylcholine-derived quaternary ammonium compounds by a LC-MS/MS method in human blood plasma, serum and urine samples.
abstract: The determination of circulating trimethylamine-N-oxide (TMAO), choline, betaine, l-carnitine and O-acetyl-l-carnitine concentration in different human matrices is of great clinical interest. Recent results highlighted the prognostic value of TMAO and quaternary ammonium containing metabolites in the field of cardiovascular and kidney diseases. Herein, we report a method for the rapid and simultaneous measurement of closely related phosphatidylcholine-derived metabolites in three different biological matrices by stable isotope dilution assay. Plasma, serum and urine samples were simply deproteinized and separated by HILIC-chromatography. Detection and quantification were performed using LC-MS/MS with electrospray ionization in positive mode. For accuracy and precision, full calibration was performed covering more than the full reference range. Assay performance metrics include intra- and interday imprecision were below 10% for all analytes. To exclude matrix effects standard addition methods were applied for all matrices. It was shown that calibration standards and quality control prepared in water can be used instead of matrix-matched calibration and controls. The LC/MS/MS-based assay described in this article may improve future clinical studies evaluating TMAO and related substances as prognostic markers for cardiovascular risk and all-cause mortality in different patient populations.
authors.affiliation: Kantonsspital Aarau, Centre of Laboratory Medicine, Tellstrasse 1, CH-5001 Aarau, Switzerland. Electronic address: christian.steuer@ksa.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Steuer
authors.affiliation: Kantonsspital Aarau, Medical University Department, Tellstrasse 1, CH-5001 Aarau, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Schütz
authors.affiliation: Kantonsspital Aarau, Centre of Laboratory Medicine, Tellstrasse 1, CH-5001 Aarau, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Bernasconi
authors.affiliation: Kantonsspital Aarau, Centre of Laboratory Medicine, Tellstrasse 1, CH-5001 Aarau, Switzerland.
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Huber
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D010713:Phosphatidylcholines / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000032:analysis* / Q000097:blood / Q000652:urine; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds
keywords: HILIC-chromatography; Isotope dilution assay; LC–MS/MS analysis; TMAO