Detection of Carbamazepine and Its Metabolites in Blood Samples by LC-MS/MS

ObjectiveTo establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry （LC-MS/MS）.MethodsThe blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18， 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol （Vacetonitrile∶Vmethanol=2∶3） were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring.ResultsThe linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients （r） greater than 0.995 6. The limits of detection were 3.00， 0.40 and 1.30 ng/mL，respectively. The limit of quantitation were 8.00，1.00 and 5.00 ng/mL，respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL，respectively.ConclusionThis method has high sensitivity and good selectivity， which is suitable for the detection of carbamazepine and its metabolites in blood samples， and can be used for carbamazepine-related forensic identifications.