Column deactivation in analysis for underivatized tricyclic antidepressants by gas chromatography with use of a nitrogen detector.

I describe deactivation treatment of the OV-17 chromatographic column to minimize adsorption of tricyclic antidepressant drugs on the solid support of the column. The procedure involves heat treatment at 399 degrees C under a low flow of nitrogen, with bleeding of OV-17 liquid phase from the injector tube into the column. The column is then conditioned with vapors of phenyldiethanolamine succinate, added to the carrier gas stream by bleeding from a coated injector glass tube. This deactivation process much improves the chromatographic performance of the column, allowing a sensitivity at the nanogram level with a nitrogen-sensitive detector. Determinations of tricyclic antidepressants in plasma with such a deactivated column results in a low CV and a linear calibration curve, reflecting the effectiveness of the deactivation.