Determination of human-use pharmaceuticals in filtered water by direct aqueous injection: high-performance liquid chromatography/tandem mass spectrometry

Abstract

each compound typically spanned three orders of magnitude of concentration. Absolute sensitivity for some compounds, using isotope-dilution quantitation, ranged from 0.45 to 94.1 nanograms per liter, primarily as a result of the inherent ionization efficiency of each pharmaceutical in the electrospray ionization process.