“…Li and his coworkers studied the solubility of the three pure amphenicols in SFE-CO 2 (Li, Maxwell, & Shadwell, 2002), but they did not explore the feasibility of recovering amphenicols in real samples. To shorten pretreatment time, several studies reported on in situ derivatization during SFE (López, Blanch, & Herraiz, 2004;Wang, Giang, & Ling, 2001;David, Campbell, & Li, 2000), in which derivatization reagent was introduced directly into the extraction chamber. This allowed the derivatization reaction to occur under the specific condition of supercritical temperature and pressure.…”