Determination of sedatives and anesthetics in plasma by liquid chromatography-mass spectrometry with a desalting system

Hideko Kanazawa, Yoshiko Konishi, Yoshikazu Matsushima, Toshiaki Takahashi

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Though liquid-chromatography-mass spectrometry (LC-MS) is a powerful tool for analysis of drugs and their metabolites, it does not allow the use of a non-volatile buffer such as phosphate buffer. We used a column-switching de, salting system in combination with atmospheric pressure chemical ionization LC-MS for analysis of sedatives and anaesthetics. The drugs examined were flumazenil, butorphanol, midazolam, lorazepam, phenobarbital and flunitrazepam. The separation was carried out on a reversed-phase column using acetonitrile-0.1 M phosphate buffer as a mobile phase. The mass spectra are almost the same as those obtained by direct analysis and the molecular ions were clearly observed. In the analysis, phosphate buffer was completely removed with the trapping column and did not interfere with ionization of the drugs in MS. The chiral separation of lorazepam was achieved on a chiral column with UV, optical rotatory detection and MS. This method is sufficiently sensitive and accurate for the pharmacokinetic studies of these drugs in biological samples.

Original languageEnglish
Pages (from-to)227-236
Number of pages10
JournalJournal of Chromatography A
Issue number1-2
Publication statusPublished - 1998 Feb 27



  • Anaesthetics
  • Desalting methods
  • Enantiomer separation
  • Sedatives

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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