GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC DETERMINATION OF ISOSORBIDE 5-MONONITRATE IN HUMAN PLASMA

A highly specific and precise method using gas chromatography-mass spe ctrometry was developed for the measurement of isosorbide 5-mononitrat e in plasma using isomannide mononitrate as internal standard. With re gard to the numerous analytical problems encountered when organic mono nitrates were determined in plasma, such as thermal instability and ad sorption, compounds were silylated before gas chromatography. In order to increase the specificity of the assay, two specific ions of the is osorbide 5-monitrate were simultaneously recorded. The accuracy of the assay was tested day to day with quality specimens spiked blind to th e analyst.