Bioanalysis of plasma acetate levels without derivatization by LC–MS/MS

Abstract

Background: The acetate ion has important physiological functions and important therapeutic applications. A rapid LC–MS/MS method is described to measure acetate ions in human plasma without chemical derivatization. Materials & methods: A 200 μl sample was spiked with the internal standard 1,2-13 C-acetate and proteins precipitated with trichloroacetic acid. The supernatant was recovered and separated under acidic conditions on a C18-column. The eluent was alkalinized by post-column infusion of methanolic ammonium hydroxide. Acetate ions were monitored on a low resolution mass spectrometer in negative ion mode. Results: Method was validated for accuracy and precision with a lower limit of quantitation of 9.7 μM and linear dynamic range up to 339.6 μM. Conclusion: The method is open for analytical improvement and adapts with metabolomic and pharmacometabolomic studies on chemicals of similar nature. Lay abstract: Recent scientific investigation has been uncovering fascinating physiological functions of the acetate ion in the body that go beyond its conventional perception as a metabolite and promise utility as a therapeutic agent in many pathologic conditions. The expanding interest in the acetate ion underscore the compelling need for a bioanalytical method that offers rapid analysis without chemical derivatization of its levels in biological samples, applies minimal manipulation to the sample, allows high-throughput analysis, and adapts easily with common metabolomic and pharmacometabolomic investigations. Such method is important in analyzing experimental, preclinical, clinical and forensic samples. The present investigation discloses an LC–MS/MS method for the analysis of acetate in human plasma to corroborate methodologies already listed in the biomedical literature.