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October 19, 2009
2:00 PM - 4:00 PM
Room Area M
A Rapid and Simple Method for Detecting Plasma Propofol
  **   Yulei Gong, M.D., Guowang Xu, Ph.D., Changsong Wang, M.D., Hui Wang, M.D., Enyou Li, M.D., Ph.D.
Anesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
Intoduction: Propofol (2,6-diisopropylphenol) is widely used for induction and maintenance in clinical anesthesia and for sedation in the intensive care unit. It is important to monitor propofol blood levels during anesthesia or sedation. It has been reported the detection of propofol blood/plasma concentrations commonly depended on liquid chromatography (LC) or gas chromatography (GC) coupled with UV, fluorescence, electrochemical detection or mass spectrometry. However, these samples were usually extracted by liquid-liquid extraction or solid phase extraction which was time consuming, blood or plasma consuming and required sophisticated procedures. In this assay, it has been developed a time-saving, trouble-saving and sample-saving method using HS-SPME-GC-MS for the quantification of propofol plasma concentrations.

Method: Plasma calibration solutions were prepared by 10 mL venous blood which was collected from five healthy adult volunteers and centrifuged at 3000×g for 10 min at 25°. Plasma was immediately stored at –20° until analyzed. Before analyzed, it was incubated in a 38° water bath for 30 min. Plasma was spiked with propofol to reach concentrations of 0, 5, 10, 20, 50, 100, 200 ng/mL. Then, 10 μL of plasma containing adequate drug amounts was added into a 20 mL evacuated silanized sealed glass vials with a chlorinated butyl rubber stopper. A SPME 85 μm PA-fiber (SUPELCO, USA) was pierced through the septum of the headspace vial at 38° for 25 min. The fiber was withdrawn and transferred into the injection port of the GC while the temperature of the injection port was set at 260°. Desorption time was 7 min.

Results: In this study, the retention time of propofol was 15.56 min. The calibration curves fitted by plotting the peak area ratio versus the concentration showed the regression lines were y = 5639.2 x - 27660, R 2 = 0.9988. Analytical recoveries of plasma propofol were given in table 1.[table1]Inter-day coefficient of variation was 2.8%, 6.3% and 4.6% at concentrations of 5, 20, 100 ng/mL respectively in plasma sample. Intra-day coefficient of variation ranged from 2.2%, 6.1% and 6.0% at concentrations of 5, 20, 100 ng/mL respectively in plasma sample.

Conclusion: HS-SPME-GC-MS method for monitoring plasma propofol concentrations was rapid, simple and less sample. It may be popularly used in clinical anesthesia or sedation and help anesthesiologists to preferably control propofol anesthesia in the futre.

From Proceedings of the 2009 Annual Meeting of the American Society Anesthesiologists.
Table 1 Analytical recoveries of propofol
Spiked concentration (ng/mL)Measured concentration (ng/mL)CV (%)Recovery (%)