Electron beam ionization mass fragmentographic analysis of tricyclic antidepressants in human plasma

A method for the measurement, in human plasma, of all tertiary and secondary tricyclic antidepressants prescribed in the United States is described. The method uses electron beam ionization GLC-mass spectrometry, employing a computer-controlled multiple-ion detector. This method, mass fragmentography, is used with internal standards for each drug. Plasma levels to as low as 10 ng/ml of the following drugs can be measured: amitriptyline, nortriptyline, doxepin, desmethyldoxepin, imipramine, desipramine, and protriptyline. Deuterium-labeled amitriptyline and imipramine are used as internal standards for those two drugs; for the other drugs, deuterated amitriptyline, nortriptyline, desmethyldoxepin, or desipramine is used. The method can measure up to 15 samples/hr, making it practical for large-scale studies of these drugs in patients. Spectra of each drug and examples of their analysis are given.