Extraction of 6-monoacetylmorphine from urine

An efficient and improved procedure for the extraction of 6-monoacetylmorphine (6-MAM) from urine is described. The procedure uses a 10% isobutanol in methylene chloride solution for initial extraction of 6-MAM, back extraction with acidic sodium acetate, and then another alkaline extraction into 10% isobutanol in methylene chloride. Compared to solid-phase extraction, this method provided significant improvement in 6-MAM recovery, along with the elimination of extraneous peaks when analyzed by GC/MS.