Determination of peptidoaminobenzophenone (2-o-chlorobenzoyl-4-chloro-N-methyl-N'-glycylglycinanilide) and its metabolites in human plasma by capillary gas chromatography negative ion chemical ionization mass spectrometry--2.

The capillary gas chromatographic negative ion chemical ionization mass spectrometric assay of peptidoaminobenzophenone (2-o-chlorobenzoyl-4-chloro-N-methyl-N'-glycylglycinanilide) (1) and its three metabolites in human plasma reported in Part 1 was changed as follows: (1) the reagent gas was changed to ammonia from isobutane; (2) each unlabelled compound (1%) was added to the deuterium-labelled compound used as the internal standard; (3) all samples were injected in the splitless mode; (4) one more metabolite, lormetazepam, was determined; (5) day-to-day reproducibility was checked in the range of 1-50 ng ml-1. Points 1 to 3 improved the preciseness with small-sized samples. Calibration curves were prepared in the range of 0.5-50 ng ml-1. Plasma levels of compound 1 and its four metabolites in 10 volunteers were measured.