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Updated: Aug 18, 2026
In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells
Published on: October 23, 2018
Quantitation of levorphanol in human plasma at subnanogram per milliliter levels using capillary gas chromatography
E T Everhart1, P Shwonek, P Jacob
1Drug Dependence Research Center, Department of Psychiatry, University of California at San Francisco, 94143, USA. bluhun@itsa.ucsf.edu
Abstract:
A gas chromatographic method for the determination of levorphanol in human plasma is described. The method utilizes extractive alkylation with tetrabutylammonium cation as the phase-transfer catalyst and pentafluorobenzyl bromide as the alkylating agent, and employs a structural analog, d-3-hydroxy-N-ethylmorphinan, as the internal standard. The pentafluorobenzyl ethers formed are separated by capillary gas chromatography and detected by electron capture. The method has good precision and accuracy for concentrations ranging from 0.25 ng/ml to 100 ng/ml and has been used to measure plasma concentrations as part of a study to evaluate the management of chronic neuropathic pain with levorphanol.
