Determination of chlorambucil in plasma by GLC with selected-ion monitoring.

A GLC technique with selected-ion monitoring is described for chlorambucil determination in plasma using [2H]chlorambucil as the internal standard. Chlorambucil is extracted from plasma with methylene chloride at pH 3 and converted to a thiazane derivative by reaction with 0.1 M sodium sulfide at 80 degrees. The carboxylic group of the chlorambucil derivative is derivatized with allyl bromide using extractive alkylation. Analysis by selected-ion monitoring was performed by focusing at m/e 305 (M) and 313. The relative standard deviation was +/- 5% (n = 5) at the 10-ng/ml level.