Comparison of supercritical CHF3 and CO2 and methanol-modified CHF3 and CO2 for extraction of sulfonamides from chicken liver.

Supercritical CHF3 and methanol-modified CHF3 were compared with supercritical CO2 and methanol-modified CO2 for extraction of sulfonamides from fortified chicken liver admixed with Hydromatrix. Results showed that solvating power and selectivity were higher for supercritical and methanol-modified CHF3 than for supercritical and methanol-modified CO2. Visual observation showed that chicken liver extract obtained with methanol-modified CHF3 was cleaner than that obtained with methanol-modified CO2. Fat precipitated in the solvent trap when CO2 was used as the extraction medium. Also, simple off-line collection of fortified chicken liver extract obtained with CO2 in a solid-phase extraction cartridge (packed with either C18 or alumina) followed by phosphate buffer-methanol (50 + 50) rinse yielded an extract that required no further cleanup for analysis.