LC/APCI-MSによるオキサゼパムグルクロナイドの分析

A high performance liquid chromatography-mass spectrometric (LC-MS) method for the determination of oxazepam glucuronide in the human urine was investigated. Oxazepam glucuronide was extracted from the urine by using Sep-Pak C18 cartridge with methanol-50 mM ammonium acetate (70 : 30 v/v) as eluent. The eluate was analyzed by LC-MS equipped with atmospheric pressure chemical ionization (APCI). High performance liquid chromatographic (HPLC) analyses were performed on a L-column (C18 reversed phase column) in the solvent system of methanol-50 mM ammonium acetate (70 : 30 v/v) at a flow rate of 1.0 ml/min. The vaporizer temperature was set to 230°C, desolvation temperature to 390°C, drift voltage to 108V, focus voltage to 96V and multiplier voltage to 2400V. Peak areas were measured using selected ion monitoring (SIM) of a base ion peak at m/z 287. The calibration curve gave a good linearity over the range of 0.25-1 μl/ml. The detection limit was 50 ng/ml by recording the base ion peak at m/z 287.