Quantification of lipoic acid in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry

J Chromatogr B Analyt Technol Biomed Life Sci. 2005 Sep 25;824(1-2):249-57. doi: 10.1016/j.jchromb.2005.07.038.


A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of lipoic acid (LA) in human plasma. LA and the internal standard, naproxen, were extracted from a 500 microl plasma sample by one-step deproteination using acetonitrile. Chromatographic separation was performed on a Zorbax SB-C(18) Column (100 mmx3.0mm i.d. with 3.5 microm particle size) with the mobile phase consisting of acetonitrile and 0.1% acetic acid (pH 4, adjusted with ammonia solution) (65:35, v/v), and the flow rate was set at 0.3 ml/min. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was linear over the concentration range of 5-10,000 ng/ml for LA. The intra- and inter-day precisions were less than 7% and accuracy ranged from -7.87 to 9.74% at the LA concentrations tested. The present method provides a relatively simple and sensitive assay with short turn-around time. The method has been successfully applied to a clinical pharmacokinetic study of LA in 10 healthy subjects.

Publication types

  • Clinical Trial

MeSH terms

  • Administration, Oral
  • Antioxidants / administration & dosage
  • Antioxidants / pharmacokinetics
  • Area Under Curve
  • Calibration
  • Chromatography, High Pressure Liquid / methods*
  • Half-Life
  • Humans
  • Reproducibility of Results
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Thioctic Acid / administration & dosage
  • Thioctic Acid / blood*
  • Thioctic Acid / pharmacokinetics


  • Antioxidants
  • Thioctic Acid