SFE-GC with Quantitative Transfer of the Extraction Effluent to a Megabore Capillary Column

Supercritical fluid extraction was directly coupled with gas chromatography such that the entire extraction effluent was directed onto the GC column. A sealed connection between the restrictor and the column ensured that no loss of analyte could occur. The elevated pressure generated in the column itself resulted in a reduced flow rate through the column, making efficient trapping possible. Metal-jacketed capillary columns were used as they can tolerate the elevated pressures required. In addition to maximizing sensitivity, very practical extraction parameters were possible. For a 25-min extraction, with a 2.2 mL/min flow rate, and the column at 40 degrees C, analytes as volatile as C-14 were trapped and separated. Trapping efficiency improved further with shorter extraction times, mild cooling of the column, or lower flow rates.