Simultaneous determination of four volatile compounds in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) by HS-SPDE-GC–MS/MS and its application to pharmacokinetic studies

• Apply HS-SPDE to the preparation of plasma samples of TCM.
• Simultaneous determination of four volatile compounds of SBP in rat plasma.
• The method provided high resolution separation and better LLOQs.
• Apply the method to the oral pharmacokinetics of four volatile compounds in rat plasma.

In this study, a headspace, solid-phase dynamic extraction method coupled to gas chromatography–tandem mass spectrometry (HS-SPDE-GC–MS/MS) method was developed for the simultaneous determination of four volatile compounds, namely, isoborneol, borneol, muscone and cinnamaldehyde, in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) using naphthalene as an internal standard (IS). The target compounds were extracted using an SPDE needle device coated with a poly (dimethylsiloxane) (PDMS) phase. The detection was achieved by GC–MS/MS in multiple reaction monitoring (MRM) mode. The optimised mass transition ion pairs (m/z) for quantitation were 95.1/67.1 for isoborneol and borneol, 85.0/67.0 for muscone, 131.0/77.0 for cinnamaldehyde and 128.1/102.1 for the IS. The parameters that affect the extraction ratio, such as the pre-incubation time, extraction temperature, number of extraction cycles, desorption volume and pH, were also optimised. The method was thoroughly validated with respect to specificity, linearity, precision, accuracy, recovery and stability. A sufficiently sensitive HS-SPDE-GC–MS/MS method was first developed in this study to determine the pharmacokinetics of volatile compounds found in rat plasma following oral administration of SBP. The method developed uses a simple procedure for plasma sample preparation and could be a promising tool for the analysis of complex volatile samples, such as traditional Chinese medicine (TCM).