Bioanalysis of plasma acetate levels without derivatization by LC-MS/MS.

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. A 200 μl sample was spiked with the internal standard 1,2-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. 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. The method is open for analytical improvement and adapts with metabolomic and pharmacometabolomic studies on chemicals of similar nature.