Ma. Stone et Lt. Taylor, Improved solvent trapping of volatiles in supercritical fluid extraction by pressurizing the collection vial, ANALYT CHEM, 72(6), 2000, pp. 1268-1274
The high flour rates that result after decompression make the trapping of a
nalytes one of the more difficult aspects of a supercritical extraction. By
elevation of the pressure on the collection vial, the now may be reduced a
nd trapping efficiency improved, considerably. The effects of different col
lection vial pressures were evaluated. The best results were obtained at 25
atm, With the collection vial at 25 atm, the trapping efficiencies of diff
erent solvents were then investigated. Also considered were the effects of
solvent volume, extraction now rate, collection solvent geometry, and restr
ictor temperature, For a 30 min exraction-with the restrictor line at 200 d
egrees C-quantitative recoveries were obtained with analytes as volatile as
chlorobenzene (similar to 90%) in 1 mL of solvent. Mild precooling of the
collection vessel allowed quantitative recoveries to be obtained down to be
nzene (94.2%).