Determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization
Article first published online: 18 DEC 2002
Copyright © 2002 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 17, Issue 3, pages 192–196, 15 February 2003
How to Cite
Chen, X., Zhong, D., Han, Y. and Xie, Z. (2003), Determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization. Rapid Commun. Mass Spectrom., 17: 192–196. doi: 10.1002/rcm.894
- Issue published online: 18 DEC 2002
- Article first published online: 18 DEC 2002
- Manuscript Accepted: 19 NOV 2002
- Manuscript Revised: 18 NOV 2002
- Manuscript Received: 25 SEP 2002
- National Natural Science Foundation of China. Grant Numbers: 39930180, 30070879
A sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to determine carbocysteine in human plasma using 2-pyridylacetic acid as the internal standard (IS). The method employed derivatization with 10 M hydrochloric acid/methanol, which significantly improved the ionization efficiency of carbocysteine. After methanol-induced protein precipitation of plasma samples, carbocysteine and the IS were derivatized and subjected to LC/MS/MS analysis using atmospheric pressure chemical ionization. The method has a lower limit of quantitation of 20 ng/mL for a 0.2-mL plasma aliquot. The intra- and inter-day precision (RSD), calculated from quality control (QC) samples, was less than 7%. The accuracy, determined using QC samples, was within ± 1%. The method offered increased sensitivity, selectivity and speed of analysis over existing methods. The method was utilized to support clinical pharmacokinetic studies of carbocysteine in volunteers following oral administration. Copyright © 2002 John Wiley & Sons, Ltd.