This document describes the method of analyzing Gabapentin in postmortem specimens using the Varian 1200L triple quadrupole LC/MS/MS. Gabapentin, an analog of the neurotransmitter GABA, is used to treat epilepsy. It also has many controversial off-label uses, such as in the treatment of bipolar disorder, social anxiety disorder, obsessive-compulsive disorder, and insomnia. The LC/MS/MS technique allows for a simple, cost-effective clean-up of the samples and provides accurate and sensitive results.
This document describes a method for identifying and quantifying gabapentin in postmortem specimens using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The procedure utilizes protein precipitation with acetonitrile as a simple, cost-effective cleanup step that requires no derivatization. The analysis employs an internal standard (Baclofen) and two MRM transitions to ensure accurate results with excellent sensitivity.
| Ionisation Mode | ESI positive |
|---|---|
| Drying Gas Temperature | 350 °C at 25 psi |
| Collision Cell Pressure | 2.0 mTorr |
| Column Type | Pursuit Diphenyl 50 mm x 2.0 mm |
| Flow Rate | 200 pL/min |
| Injection Volume | = 25 pL |
The peak-to-peak signal-to-noise ratio of gabapentin at 1.0 pg/mL represents the reporting limit.
Baclofen is dissolved in water to a working concentration of 1.0 mg/mL and added as an internal standard.