Takaichi K., Kumooka Y., Ohki H.

Identification Research Laboratory, National Research Institute of Police Science, 6, Sanban-cho, Chiyoda-ku, Tokyo 102, Japan

SFE has many excellent points for the replacement of liquid-liquid extraction (LLE) and solid phase extraction (SPE) methods (1). However, the SFE method is not so popular in the forensic and clinical toxicological fields, because the instrumentation is expensive and because of breakdown of the instrument, that is, restrictor becomes plugged easily when applied to the biological sample containing a lot of moisture (2). At the same time, the extraction efficiency is decreased.
In a previous paper (3), we reported a SFE method combined with freeze-drying, to reduce the problem of the LLE and SPE methods, which can easily extract drugs from biological samples without considering the need for deproteinization or the liquid-liquid distribution ratio (kind and amount of the extraction solvent). The extraction efficiency of the drug was high.
In this report, an evaluation has been made of whether nitrazepam, triazolam, alprazolam, and their related metabolites can be extracted or not from blood samples with the SFE method combined with freeze-drying.

References

1. Larry T. Taylor, Supercritical Fluid Extraction, Wiley-Interscience, 1996.
2. Bowadt S., Howthorne. S. B., J.Chromatogr., 1995, A703, 549-571.
3. Takaichi K., Shinohara T., TIAFT Meeting Interlaken, 1996.