National Research Institute of Police Science, 6, Sanban-cho, Chiyoda-ku, Tokyo 102-0075, Japan

This study concerned the direct extraction of drugs from blood by SFE combined with fillers. The aim was to develop a simple, fast and inexpensive SFE extraction method which does not require deproteinization and which is not affected by liquid-liquid distribution ratios. Cellulose powder (0.2 g), the filler (appropriate amount), and absorbent cotton (0.2 g) were sequentially packed into the extraction vessel (10 ml). A blood sample (1 ml) containing 16 ng of diazepam as the target drug was added to the vessel, which was then set in the device. As the supercritical fluid passed through successive layers of the filler materials in the extraction vessel, protein in the blood was filtered out. At the same time, a colorless and transparent filtrate was easily obtained without the need for deproteinization. Fifteen kinds of drying agents and adsorbents, such as molecular sieves, were used as fillers. Quantitative analysis of the extracts was carried out by GC/MS.

The results showed that recovery of diazepam from whole blood was high as long as the extraction conditions were considered. Filling materials which gave good recoveries were molecular sieves, diatomaceous earth, silica gel, magnesium sulfate (anhydrous), and sodium sulfate (anhydrous). In particular, when molecular sieve 5A was used, recovery was 100%. This SFE method was simpler, faster, and less expensive than conventional methods.