GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC DETERMINATION OF URINARY 1-AMINOCYCLOPROPANECARBOXYLIC ACID IN MICE USING A DEUTERATED INTERNAL STANDARD

A gas chromatographic-mass spectrometric method is described for the d etermination of 1-aminocyclo-propanecarboxylic acid in mouse urine usi ng the 2,2,3,3-[H-2(4)] isotopolog as an internal standard. Samples (0 .1 ml) were extracted using an exchange resin, then derivatized with p entafluoropropanol and pentafluoropropionic anhydride at 100 degrees C for 25 min. Gas chromatography was performed on a (5% phenyl)methylpo lysiloxane column and detection was by selected-ion monitoring of M - CO2CH2CF2CF3 fragment ions. The method provided high response linearit y (mean r = 0.999) and precision (< 5% coefficient of variation). Afte r orally dosing mice with 1-aminocyclopropanecarboxylic acid (300 mg/k g), 46 and 10% of the dose was excreted unchanged in the 0-24 h and 24 -48 h urines, respectively.