Liquid-liquid extraction systems for THC-COOH and benzoylecgonine.

Because DuPont Instruments has discontinued commercial availability of the PREP automated sample processor, an alternate method for the general extraction of THC-COOH and benzoylecgonine from a urine matrix in the military drug screening laboratories' standard procedure is needed. The liquid-liquid extraction method presented for isolation of THC-COOH uses extraction with isobutanol-hexane followed by back extraction into an aqueous alkaline medium and results in a percent recovery of 104.24 +/- 9.71%. The isolation of benzoylecgonine involves extraction into ethanol-methylene chloride followed by evaporation and derivatization with 1-iodopropane; recovery is 102.43 +/- 3.13%.