Determination of volatile residual solvents in traditional Chinese medicines by headspace solid-phase microextraction and cryogenic gas chromatography with flame ionization detection.

A method based on headspace solid-phase microextraction and cryogenic gas chromatography with flame ionization detection was developed for the determination of volatile residual solvents in traditional Chinese medicines. A laboratory-made cryogenic chromatographic system was used for the separation of 15 kinds of residual solvents. During the analysis, a 65 microm PDMS/DVB fiber was used to extract the residual solvents, the extraction time was controlled at 0 degrees C for 15 min, and the NaCl content of the sample was maintained at 30%. The limits of detection ranged from 0.08 (for octane) to 5000 microg/L (for ethanol), and the relative standard deviations were < 8%. The recoveries from spiked samples ranged from 88 to 112%. Trace levels of residual solvents in several traditional Chinese medicines were effectively identified and quantified.