Liquid trapping after supercritical fluid extraction with modified carbon dioxide

A polarity test mix consisting of acetophenone, N,N‐dimethylaniline, naphthalene, 2‐naphthol, and n‐tetracosane was spiked onto sand and extracted with carbon dioxide modified with acetonitrile, methanol, or toluene. The extracts were collected in chloroform, hexane, methanol, or a mixed collection solvent consisting of equal parts chloroform‐hexane‐methanol. The mixed collection solvent which showed excellent recoveries for pure CO2, had the worst recoveries of all the collection solvents with modified CO2. Overall hexane was the best collection solvent studied for these analytes under these extraction conditions.